Tropical Tidbits from the Tundra

Alex bears down on northern Mexico and south Texas

By: Levi32, 5:59 PM GMT on June 30, 2010

If you can, playing the video in HD makes it much easier to see things. The video will play in low quality by default.



Hurricane Alex has strengthened overnight, as hurricane hunters found a pressure all the way down to 958mb, which rose to 961mb by the time they left the storm which indicates he may be leveling off, but Alex really did deepen last night and now has the pressure of a Cat 3 hurricane. However, the NHC has kept Alex down at a low-end Cat 1 despite this, based on recon winds, but there is no way the winds will stay that low. Alex may be large, but winds will be Cat 2 and approaching Cat 3 force at landfall, as the coast likes to tighten the eyewall and catch winds up to the pressure if they were previously lagging behind. I don't expect too much more strengthening out of Alex, and probably a steady intensity or slight weakening up until landfall, as some dry air in the western core is limiting development of the CDO and eyewall, which is clearly seen in visible satellite and Brownsville radar.

Since last night Alex has slowed town and turned northwest, which was a bit unexpected since the NHC and every track model had locked on to a straight west shot into the Mexican coast near 24N. Yesterday morning I had concerns that Alex would try to make a NW move before landfall and sneak closer to the southern periphery of the ridge which is supposed to steer him west. This ridge is way up over South Dakota, and my worry was that he would sneak closer to the border and give south Texas more than they bargained for. I all but gave up on this idea completely yesterday afternoon after Alex made his due west turn, as I thought the ridge had finally caught him and he was committed to the coast at that point, but apparently my concerns were still valid, as Alex is gaining latitude and will make landfall much closer to the border than anticipated yesterday.

Latest radar imagery shows Alex may be trying to finally turn left towards the coast and go in near 25N, and he will likely commit to a real west turn now, but storms near the Rio Grande like to avoid the river, and like we saw with Dolly in 2008, we might have to watch for Alex to try to make a couple northerly jogs and sneak just north of the border. At this point it doesn't really matter whether landfall is north or south of the border, as Alex is a massive storm, comparable to Ike in size, and a large stretch the south Texas and north Mexican coasts will be receiving hurricane-force winds from this storm, as well as the storm surge. A messy and prolonged landfall would only be bad news for people in this area, as that of course means more rainfall, which is already heavy across a very large area, and prolonged hurricane-force winds for a good portion of the coastline. This is a nasty situation for these folks, and for many may be like a Dolly Dejavu.

I don't expect much more strengthening from Alex with the dry air getting entrained into his core by his large circulation, and as of this writing the new recon plane found a pressure rise to 962mb, so Alex may have peaked, and will hopefully slowly weaken up until landfall, although if he completes an eyewall replacement cycle we may see another burst of deepening right before landfall. However, winds will almost certainly increase to at least Cat 2 force upon landfall, and hopefully the NHC realizes this or people will get surprised with stronger winds than they thought.

I will hopefully be able to post an update later this evening as Alex nears landfall, which is about 12 hours away.

We shall see what happens!

Brownsville Radar:



Hurricane Alex Visible Satellite (click image for loop):



Hurricane Alex Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 6:26 PM GMT on June 30, 2010

Permalink

Alex 36 hours from landfall

By: Levi32, 4:55 PM GMT on June 29, 2010

If you can, playing the video in HD makes it much easier to see things. The video will play in low quality by default.

Note: I said HURRICANE Alex 4 seconds into the video right off the bat....obviously that was a mess-up I apologize. I'm not very clear-headed this morning as my lack of sleep is catching up to me. Please bear with me in the video.



Tropical Storm Alex is approaching hurricane intensity right now as a CDO tries to form over the center, and hurricane hunters found a central pressure of 983mb. This is rather low for a tropical storm, but Alex is massive in size which could explain the spread out pressure field. Still, this looks like a hurricane to me and should really be upgraded. Some dry air may have gotten punched in to Alex's NW quad by the upper trough that was shearing it yesterday, and some dry air may have come from the cold water environment Alex was over yesterday, but there no longer seems to be a real source for this dry air and I don't expect it to be a big issue for Alex. The storm has now moved over the warmer waters north and west of the Yucatan shelf, and the new CDO blew up immediately after hitting these waters. As I opined yesterday, from now until landfall Alex should begin fairly steady strengthening, and I still expect him to be a Category 2 hurricane.

Alex is about 36 hours from landfall, sometime Wednesday night local time. The models have come into much better agreement now on the track, and they usually do by the time we're a day and a half from landfall. The consensus is now for a landfall near 25N on the Mexican coast, which was my original forecast from Saturday morning, but I did shift north a little bit yesterday. Landfall is now likely anywhere from the Mexican coast near 24N to Brownsville, Texas. 25N Mexico looks like a good bet to me. Alex is currently in the process of gradually curving from a NNW motion to a WNW motion that will take him into the western gulf coast, due to a ridge building into the plains which is forcing him back towards the west. There is still a chance that Alex tries to sneak northwest at the last second and get into southern Texas, as the ridge is going to stay pretty far north at 40-45N over the plains, and Alex may try to get closer to its southern periphery, but it is now starting to look likely to be a landfall south of the TX/MX border, but still close to Texas.

Residents of Texas should be aware that Alex's size makes him a danger to them even if Mexico gets the landfall, and hurricane warnings are up all the way to Baffin Bay. Tropical storm-force winds and heavy rain will extend even farther north of that, and much of the Texas coastline will have to deal with nasty and potentially dangerous weather tomorrow.

Elsewhere....a trough-split is looking likely to occur near Florida in several days after Alex is gone, and that area will have to be watched for home-grown mischief as a front stalls out under the trough-split with the big ridge building over the top in the eastern US. The African wave train will continue to be watched, as the MJO is once again returning to our area of the world and a couple of these waves look promising to become trouble-makers as they approach the Caribbean. There are no immediate concerns for development in the next 48 hours.

We shall see what happens!

Tropical Storm Alex Visible Satellite (click image for loop):



Tropical Storm Alex Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 5:10 PM GMT on June 29, 2010

Permalink

Alex to threaten Texas as a potentially strong hurricane

By: Levi32, 5:40 PM GMT on June 28, 2010

If you can, playing the video in HD makes it much easier to see things. The video will play in low quality by default.



Tropical Storm Alex is finally starting to clear the Yucatan, after hanging around within 50 miles of the coast for over half a day. A NW to NNW motion has ensued, and Alex should finally start to pull away from the land today. Land interaction has kept Alex from significantly reorganizing yet, and the deep convection that tried to fire over the center last night has now dissipated and the center is partially exposed. I suspect that upwelling of cold water near the coast has had a lot to do with this, as although SSTs were 28C when Alex came off, the warm water is extremely shallow, and although Alex is only a tropical storm, I have a feeling he has upwelled some colder waters underneath him due to his stalling near the coast yesterday. Warmer, deeper waters lie north of 22N and west of 92W, and once Alex gets out of that box, I expect he will be able to quickly approach hurricane strength. Alex is also getting sheared a little bit from the northwest by an upper trough over the north gulf coast, but this will be lifting out within 24 hours, allowing a Alex's very nice upper high to expand north again.

Alex has actually strengthened in a technical sense since coming off the Yucatan, and is now a 60mph tropical storm, but that was just his surface winds catching up to his central pressure, which was 991mb coming off. This was more typical of a borderline hurricane than a tropical depression, and the winds which naturally slowed over land due to friction are now catching back up to the pressure. Alex's pressure lowered temporarily to 989mb during the convective burst last night, but has since risen back to 991mb according to hurricane hunters this morning, which makes sense given his satellite appearance. I expect Alex to perhaps organize a little better today but no significant strengthening until he gets out of the box south of 22N east of 92W where the water is cold and shallow. Once he moves into the warmer, deeper waters, I expect steady strengthening into a hurricane to ensue.

Alex's track is becoming less difficult to pin down here as we go forward in time. The big-hitting global models, which were at outright war with each other yesterday, have come into better agreement this morning. The ECMWF last night shifted north to what my forecast track was on Saturday morning, and the GFS and Canadian have shifted south to a south Texas landfall. I have no major changes from my forecast on Saturday morning. I had Alex coming into Mexico near 25N but leaving the door open for south Texas, and now that that door is wide open, I will be extending the forecast north a little bit. I think Alex will come in anywhere between my old forecast on the Mexican coast at 25N, and Rockport, Texas, which is northeast of Corpus Christi. That's a 200-mile stretch of coastline, which I outline for you in the video.

The forecast reasoning is and actually has been quite simple, but the models have been giving us fits with all kinds of different scenarios but with seemingly the exact same steering setup in the atmosphere. A longwave trough coming into the northern US right now is weakening the subtropical ridge over the Gulf of Mexico, and the resulting weak steering currents are the reason why Alex slowed to a crawl off the coast of the Yucatan. This weakness will allow Alex to move NW or NNW and gain a lot of latitude over the next couple days. After 36-48 hours, on Wednesday, the trough will be moving east into the eastern seaboard and a big ridge behind it will be building into the great plains. This should curve Alex back towards the WNW, taking him on course to a north Mexico or south Texas landfall. The ridge center will be all the way up over Nebraska and Iowa, which is why I think the door is very open for Alex to get far enough north to hit Texas.

Alex has the potential to be a formidable hurricane at landfall, and the farther north landfall takes place, the more time he will have over water to strengthen. Right now he has about 60-72 hours before landfall. I expect significant strengthening of Alex to begin in about 24 hours when he moves over that warmer water, and in this pattern a hurricane is almost guaranteed. Alex will have a nearly perfect upper pattern over him with a symmetrical upper high and excellent outflow channels, similar to what he had coming into Belize, and we saw how fast he wanted to wind up there.

The fact that he will be curving westward at landfall speaks to the fact that there will be no trough trying to recurve the storm during landfall, meaning that there will be little wind shear. This is going to be one of those rare June storms that is strengthening at landfall on the north gulf coast, as most of these early-season storms are moving north or northeast at landfall and getting sheared by their trough. Alex could easily become a Cat 2 hurricane, and a major hurricane is not out of the question, especially if he makes landfall in Texas, not Mexico. This is going to be a nasty situation with a deepening hurricane coming ashore likely sometime on Thursday, and even if Alex comes into northern Mexico, south Texas will still get lashed badly as Alex's circulation is very large. I hope everyone is prepared.

Elsewhere....there are no immediate threats for tropical development in the Atlantic. The African wave train will continue to be watched during the next couple weeks. A strong wave poised to emerge in the Atlantic later today may be a threat down the road, and will be monitored closely. The ITCZ in the central Atlantic will also be monitored as there is a disturbance trying to form a spin, but is not an immediate threat to develop.

We shall see what happens!

Tropical Storm Alex Visible Satellite (click image for loop):



Tropical Storm Alex Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 6:46 PM GMT on June 28, 2010

Permalink

Tropical Storm Alex to be a big problem for Mexico

By: Levi32, 5:19 PM GMT on June 26, 2010



Well the 2010 Atlantic hurricane season is now underway. Tropical Storm Alex has formed in the western Caribbean north of Honduras as expected, and looks very healthy this morning. The core of the system is still a bit disorganized, which is evident on visible satellite imagery and a microwave pass from 3 hours ago. Belize radar shows the heavy rain bands moving ashore over Belize and Mexico.

Alex has the look of a 50-55kt (60-65mph) TS, not a 40-knot TS like the NHC has it at the 11am advisory. If you look at the NDBC site you will see a ship at 20.8N 85.3W reported 39kt sustained winds and a 1008mb pressure. That's around 200 miles north of the center! A different ship to the north of that at 21.3N was reporting 32kt sustained winds. When you have a system that looks this good on satellite, there is no way its wind maximum is that far away from the center. 40kts max winds? No way. The winds have to be higher than that at the center and the pressure is certainly lower than 1003mb. A recon plane is about to enter the storm as I write this so we will find out soon if I am right.

The track of this storm is becoming a little more clear this morning. The ECMWF, which started out far to the east, has led the way in bringing the models west, and the consensus is now mostly south of the US. Louisiana can probably forget having to worry about a direct hit from this, and even the Texas coastline down to Corpus Cristi can probably rest easier. I have this storm slightly north of the 11am NHC track, which takes into Mexico just south of 24N. I have it going in near 25N, as I still think it will try to sneak farther north in the gulf. The longwave trough diving into the eastern US in 3-4 days won't stick around long, but the pattern argues that there has to be at least some weakness in the ridge over the gulf, and I believe Alex will respond to this by curving northwest and slowing down. Once the trough starts to leave the ridge will build back over the plains and force Alex back west towards the west gulf coast.

If Alex does make it to 25N, it could still be a nasty storm for the south Texas coast and the Rio Grande valley, because as we saw there are ships reporting TS-force winds 200 miles north of the center, and this storm is obviously large on satellite. South Texas may have to worry about heavy rain and strong winds even if Alex moves south of them into Mexico. There is still an outside chance that Alex tries to sneak all the way up to a Texas landfall, but I am kind of doubting that. This is looking more like an all Mexico problem now in terms of direct hits. Again, though, I think Texas will be affected by the storm area.

Alex will be moving inland over the Yucatan near northern Belize tonight, and should spend roughly 24 hours crossing the Yucatan Peninsula. The fact that this isn't a powerful hurricane means that it will be far less damaged during the crossing, as tropical storms don't have as much of a core to destroy as a major hurricane does. A major hurricane ends up fighting with itself as it crosses a big land mass like the Yucatan, and big storms that make that crossing rarely regain their former glory. Alex, however, if he remains organized during the crossing, has the potential to restrengthen very quickly when he pops out the other side, and intensification will likely resume over the western gulf.

Alex has a nearly perfect upper anticyclone aloft over top of it, giving it an absolutely gorgeous outflow pattern. This pattern only gets better as he moves into the western gulf, with the GFS 200mb forecast this morning showing a textbook outflow pattern around the storm. I could see this easily becoming a hurricane and possibly knocking down a couple categories. Mexico may have to deal with a Cat 2 hurricane for a 2nd landfall. A major hurricane in the gulf even isn't out of the question, but it will greatly depend on how Alex looks after crossing the Yucatan, which is a rough ordeal for any tropical cyclone.

Elsewhere....Invest 94L continues to interact with the TUTT. This tropical wave north of the Antilles is still a possible mischief-maker during the next few days, but chances of development are low. Bermuda should be watching this for delivering a possible shot of heavy rain to that area. A strong tropical wave over western Africa will be moving out over the eastern Atlantic in a few days. The models are hinting at development of this system, and it will be monitored. The season looks to be kicking off, and this is likely just the beginning of a major roller-coaster ride.

We shall see what happens!

Tropical Storm Alex Visible Satellite (click image for loop):



Tropical Storm Alex Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 5:32 PM GMT on June 26, 2010

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93L nearly a tropical depression, will threaten west gulf coast next week

By: Levi32, 4:28 PM GMT on June 25, 2010



Invest 93L is starting to show its true colors this morning. The mid-level energy has mostly caught up to the surface center, located northeast of Honduras, and the focus of heat has now shifted far enough west that it can feedback with the low center and start to ramp up the system. Now that the system is finally vertically stacked, the gates have opened for the race to begin. Convection is now firing all over the circulation from the Yucatan to Jamaica, including some heavy cells over the center. A buoy near the center reported a pressure of 29.70 inches of mercury (1005.7mb) last night, which is very respectable. The buoy is now reporting strengthening SSE winds, a switch from the easterlies of the last several days, which is indicating the low is moving northwestward to the west of the buoy and intensifying.

This is very close, if not already, a tropical depression, as the circulation was closed last night per an ASCAT pass, and it appears to still be closed and strengthening this morning underneath strong convection. I fully expect this to be tropical storm Alex before reaching the Yucatan in a couple days or so. I expect strengthening up until landfall on the Yucatan will be gradual, as the system is still large and working on bundling the heat into a tight circulation, but 93L should have no problems developing and strengthening. Once these things get stacked, it's off to the races.

Environmental conditions should remain favorable for strengthening of 93L after crossing the Yucatan, and if it emerges in the gulf well intact, strengthening will likely resume, and I cannot rule out intensification into a hurricane. SSTs are plenty warm and the upper high will be following the system providing good outflow and low wind shear, so there is no reason that this shouldn't go through the normal motions of strengthening. This system will be unlike most early-season openers which are usually sheared to the east, like Arlene of 2005 which came up into the gulf out of the Caribbean as well. This system should be cause for concern for the western gulf coast.

The models are still in disagreement on the strength of the longwave trough that is supposed to dive into the eastern US and try to recurve 93L in 3-4 days. The ECMWF is still taking this straight west into Mexico, and some of the hurricane models recurve this all the way into Florida, which I think is overdone. Narrowing down the possible landfall location will be difficult, but I believe everyone on the Louisiana coast west of the Mississippi all the way down to central Mexico should be keeping a close eye on this, as it is likely to get somewhere in the northwest gulf.

Elsewhere....a tropical wave northeast of the Antilles is interacting with the TUTT and producing heavy convection over an area of low-level vorticity. This will not be developing within the next 48 hours, but the TUTT is about to split with a tail-piece backing away to the southwest as an upper ridge builds over top of the area, and this feature may have to be watched for mischief as it moves northwest out into the western Atlantic, and Bermuda may have to watch this system. (Edit: During this typing this area was designated Invest 94L). There are no other areas of immediate concern for tropical development during the next 48 hours.

The tropics are starting to heat up, as I have opined here that they would as we near the end of this month and into the early weeks of July, where we could see the real kick-off to the season. So far, we are definitely nearing game time.

We shall see what happens!

Invest 93L Visible Satellite (click image for loop):



Invest 93L Track Models:



Invest 94L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 4:31 PM GMT on June 25, 2010

Permalink

93L still slow to organize, but remains a possible threat

By: Levi32, 4:49 PM GMT on June 24, 2010

Here's another video. I'm still getting used to doing these things but I hope you enjoy.



Invest 93L remains generally disorganized this morning, with the surface center backing WSW southwest of Jamaica towards the coast of Honduras and Nicaragua, and most of the thunderstorm activity remains well east of the center. This area of convection, though, despite only being associated with a mid-level feature, has become more consolidated since yesterday, and low-mid level vorticity has increased between Jamaica and Haiti. The tropical wave that was passing south of Puerto Rico yesterday is becoming a part of this mix as it catches up to 93L's territory, and as I mentioned yesterday, it will be interesting to see if the area of greatest heat concentration tries to spin up a new low center all on its own and discard the current center, which is not in a good place for development right now in relation to the rest of the system. 93L needs to be vertically stacked, but right now it is still a mess of competing low-mid level features with the surface center, which, for now, remains dominant.

Although 93L is still struggling with internal problems, the surrounding environment continues to be favorable for development, with a decent upper high over the system providing good ventilation and low wind shear. SSTs are also insanely high throughout the Caribbean, especially west of 75W. Today will be key because we will see whether 93L's surface center strengthens or weakens, and whether convection will want to start firing near it instead of all off to the east like it is now. The movement of the surface center will also be interesting to watch, as its current WSW motion is taking it quite close to the coast of Honduras, and although a turn back towards the west or WNW should ensue later today, land interaction may already start to play a role here.

The models are all initializing the naked surface center, and as a result the tracks have shifted much to the west compared to the last few days, which makes lots of sense if the surface center remains dominant. This would result in 93L moving over the Yucatan and popping out the other side, either in the Bay of Campeche or in the west-central gulf. At this point it might finally get its act together if it can become vertically stacked, but the 0z ECMWF last night showed an interesting situation, where the surface center develops into a tropical storm on the model in the southern Bay of Campeche and moves inland, but a piece left back behind to the east comes across the Yucatan and develops into a second storm, which moves northwest into southern Texas. This is what I have been mentioning about with the mid-level center to the east. That is where the heat seems to want to bundle, not over the surface center, but with the mid-level center, and this feature has potential to cause mischief all on its own if the surface center weakens and allows a new center to form underneath the mid-level feature. The mid-level center could also catch up to the surface center now that it has slowed down, and the two could become vertically stacked in the very western Caribbean. It will depend a lot on what happens today.

Regardless of where development takes place, if it takes place at all, 93L will likely continue slowly WNW, and if its center remains where it is now it is likely to move into the Yucatan, but a reformation farther east would limit interaction with the Yucatan and give a clearer path into the Gulf of Mexico. Either way, a curve to the northwest will happen eventually, as although the longwave trough moving into New England won't be strong enough to recurve the system, it will open up a path towards the north gulf coast, if 93L is far enough east to take it.

Overall, this remains a complex situation with no clear-cut solution, and the situation will simply have to be monitored. I continue to give 93L a moderate chance of becoming a tropical depression. The entire gulf coast as well as Mexico should watch this system closely.

Elsewhere....a tropical wave along 53W is generating moderate convection as it interacts with the TUTT in the central Atlantic. This wave will be heading northwest to the north of the Caribbean, out into the southwest Atlantic. After this feature busts through the shear zone, it might be something interesting to watch as it moves under marginally favorable upper-level winds. For now, it is not an immediate concern. There are no other areas of concern for tropical development.

We shall see what happens!

Invest 93L Visible Satellite (click image for loop):



Invest 93L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 4:50 PM GMT on June 24, 2010

Permalink

93L disorganized, but could still be a big problem

By: Levi32, 4:21 PM GMT on June 23, 2010

Below is a video to go along with today's update. Some of you will remember I tried to do these once before for a little while but had to stop. I now have my own computer so I can attempt to do some of these again if you guys think they would be a good addition. I know a lot of you appreciate visual representation, as do I. This is good practice for me in a variety of ways, and I would appreciate any feedback on whether I should continue trying to do these and make them better. You have to realize I have never used my voice to communicate ideas about the weather, so I'm a bit rusty doing anything besides typing lol. This first one got a little long, but it's just a practice run.

The video quality should be fine, just make sure it's at least 360p.



Invest 93L remains rather disorganized this morning, though it looks a little better than yesterday. Showers and thunderstorms are mostly off to the northeast of the "center" which is being defined by the NHC as that area of low-level turning south of Jamaica. This area, however, is mostly void of convection, and although this may end up becoming the dominant center, I wouldn't be surprised to see a new low form farther to the north and east under the mid-level low within the area of building heat. There is another tropical wave currently moving south of Puerto Rico with a decent 850mb vort max with it, and it will be interesting to see if this feature gets in there and tries to spin up a circulation under 93L's mid-level center.

The environment remains mostly favorable over 93L with an upper level ridge in place providing good ventilation and low wind shear. This ridge will be following it westward over the next few days, and unlike most season openers, shear should not be a big problem for this system as it tries to develop. Based on the environmental conditions and the hot SSTs beneath it, 93L should, in theory, develop. It is hard though to bundle this much heat when you have such a large amount of it that's spread out over a big area, and it is not surprising to see this system taking its time organizing. It will need several days to consolidate, but if it finally does, it's going to be scary as this thing will want to take off in a hurry.

The ECMWF is right back on board with a scary 0z run last night showing a 950mb hurricane making landfall in Louisiana. Intensity forecasts shouldn't be focused on too much right now until we actually have a well-defined system, but you can see the potential that the models are showing, and this system could easily become a hurricane in the Gulf of Mexico if it does develop. This would be very different than most season openers in June, which are usually weak and sheared off to the east like Arlene in 2005. There is reason to be very concerned about this, and the residents of the entire gulf coast should keep an eye on it.

The track of a potential system is still iffy, and will remain that way until we actually have a developed system. Timing will be a big issue as a longwave trough diving into the eastern US will be trying to recurve anything sitting in the gulf, depending on where that something is at the time. The system's strength would also play a key role in determining whether it gets picked up by the trough, as a stronger system would be more likely to "feel" the weakness and curve northward. I'm still not ready to really make a call on this, as I like to see a developed and consolidated system first, and there is a lot of room for the model consensus to change depending on where the system finally anchors itself.

Overall...I still give 93L a moderate chance of developing into a tropical depression before the weekend.

Elsewhere....an amplified tropical wave along 45W will be watched as it comes west into an area of increasing moisture. This feature will be shooting in north of the Caribbean and will likely recurve out to sea, but will be watched for mischief nonetheless. There are no other areas of concern for tropical development in the Atlantic.

We shall see what happens!

Invest 93L Visible Satellite (click image for loop):



Invest 93L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 4:23 PM GMT on June 23, 2010

Permalink

93L remains disorganized, but still a threat

By: Levi32, 4:20 PM GMT on June 22, 2010

Invest 93L remains fairly disorganized this morning. Thunderstorms are not as consolidated as they were yesterday, although a nice complex of heavy thunderstorms has developed south of the Dominican Republic. Vorticity (spin) of the system remains low. The main 850mb vort max is located near the complex of thunderstorms south of the Dominican Republic.

Based on this, one might be tempted to say that a new surface low will form here, and that would be a nice guess due to all the mid-level spin evident in the satellite presentation and the consolidated convection, but I think it is more likely that a new surface low will form farther southwest, south of the western tip of Haiti. This is because although there is low-level vorticity associated with the area of thunderstorms south of the Dominican Republic, the southeast trade winds are still running strong underneath the system, and show no sign of forming a surface circulation. Farther southwest, we observe that the trades slow down as they turn easterly, causing air to pile up, and there is a band of monsoonal southwesterly winds off the northwest coast of Columbia associated with the monsoon trough that will likely play a key part in getting a surface circulation going. These promote spin as they meet the easterly trade winds, and we should see vorticity gradually shift southwestward towards this area during the course of the day.



The problem is that there is little thunderstorm activity in this area, and the main focus is off to the northeast. The latest GFS runs continue to show no development of 93L, and the GFS does have a valid point based on what we're seeing here. This is a large buildup of heat in the central Caribbean, and sometimes it takes so much effort to actually bundle all that energy that it never happens, and the heat remains spread out in a fashion that doesn't allow a tight circulation to form. The ECMWF has also significantly backed off from the aggressive development that it was showing a couple days ago.

Despite this, upper-level conditions will remain conducive for development as an upper anticyclone is sitting above the system, providing low wind shear and upper divergence. The TUTT is just off to the west sitting over the NW Caribbean, and is providing a conveyor belt of southwesterly upper winds which is helping to carry air out of the top of 93L, which aids in ventilating the system. SSTs are very hot and ocean heat content is high, so there are no limitations on 93L there. 93L is also embedded within a very moist environment, set up in part by ex-92L. Pretty much everything is in place for development, and these kinds of systems can take days to organize. The heat just has to get bundled, and sometimes that never happens, but it still has a good chance to here. There is lots of time left. I give 93L a moderate chance of becoming a tropical depression by Friday.

93L will be continuing in a general WNW direction over the next few days, and will eventually curve northwest into the Gulf of Mexico, likely near the Yucatan Channel. From here the steering pattern becomes more complicated and fragile as a longwave trough tries to break down the ridge, and 93L's future track after this point will largely be determined by its strength, as a stronger system would be more likely to feel the weakness in the ridge and turn north. The entire gulf coast as well a Mexico should be keeping an eye on this system.

Elsewhere....there are no immediate threats for tropical development.

We shall see what happens!

Invest 93L Visible Satellite (click image for loop):



Invest 93L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 4:31 PM GMT on June 22, 2010

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Invest 93L a big threat

By: Levi32, 4:01 PM GMT on June 21, 2010

A new disturbance is forming in the eastern Caribbean, and is the most concerning of the season so far. A low pressure area has formed along a well-defined tropical wave along 68W. This low has been designated Invest 93L. Widespread moderate-heavy convection is associated with this wave, but the surface low is not closed.



For the first time this year, we have a tropical disturbance with an environment ahead of it that is conducive for significant development. An upper-level ridge is currently building over 93L, providing low wind shear of 5-10 knots and good divergence aloft. Even better is that the TUTT is still sitting off to the west over the northwest Caribbean, and as this lifts out and backs away over the next few days ahead of 93L, it will provide excellent ventilation of the system.

Ex-Invest 92L, now a tropical wave in the northwest Caribbean, is instrumental in setting the stage up for 93L. Although it is located underneath the TUTT and is sheared to pieces, ex-92L is still contributing a large amount of moisture to the area, and is serving to clear out any dry air that was lingering in the western Caribbean, leaving a very moist environment out in front of 93L. Ex-92L is also lowering surface pressures and slowing down the air flow in the western Caribbean, increasing surface convergence. This is also preparing the way for 93L, which will have a very favorable environment in the western Caribbean. Also working in 93L's favor are the slow trade winds running through the Caribbean right now. Usually the central-eastern Caribbean is a burial ground for tropical waves, and is generally a dead-zone for tropical development, but the fast trade winds that are usually screaming through that area are pushed off to the east right now and winds are lighter than usual in the central Caribbean, allowing air to converge and rise around 93L.

The ECMWF is very aggressive with this system, curving it north into the Gulf of Mexico and winding it up into a major hurricane. The model, however, has been going through wild swings on the track forecast, and both track and intensity should regarded with little merit as we don't even have a developed system yet. It is, however, concerning to see the ECMWF all over this, and the reality here is that a system like 93L curving up into the Gulf of Mexico right now under favorable environmental conditions with SSTs as hot as they are, would have no problem at all becoming a hurricane. I know we are only talking about our potential first named storm of the year, but this is not likely to be one of those heavily sheared tropical storms that we are used to seeing for a season opener. This is the real deal.

With SSTs and ocean heat content through the roof in the western Caribbean, I expect 93L will have no problem gradually organizing over the next couple days, and see nothing really stopping it from becoming a tropical cyclone. I cannot speculate too much on the eventual track of the system until I see exactly where it will consolidate, but it is likely 93L would eventually curve northwest into the Gulf of Mexico due to a weakness in the mid-level steering ridge to the north. Whether this runs into the Yucatan first is hard to say yet. Again I would like to see it consolidate and show development first, but the system will be heading towards the WNW over the next couple days.

Overall, this is a situation that should be closely monitored. I give 93L a high chance of developing into a tropical depression within the next 4 days, and we have a good chance of seeing it eventually named Alex.

Elsewhere....there are no other areas of immediate concern for tropical development.

We shall see what happens!

Invest 93L Visible Satellite (click image for loop):



Invest 93L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 5:34 PM GMT on June 21, 2010

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92L a possible threat down the road; watching the African wave train

By: Levi32, 3:39 PM GMT on June 18, 2010

Invest 92L, which apparently was not discontinued, has crossed the Antilles Islands, and has degenerated into a tropical wave. Although 92L didn't begin as a tropical wave, the properties of a dissipating westward-propagating tropical cyclone allow us to call it a tropical wave. 92L put on quite a show last night, with the longest-lasting MCC (12 hours) of its lifetime, which blew up east of the center. This has collapsed overnight, as wind shear was just too much to allow the surface center to get underneath and feedback. The center of low-level turning along the wave axis is currently located west of Guadeloupe, moving westward.

Although 92L will likely keep trying periodic burstings of convection east of its wave axis, I expect nothing as large as last night due to its circulation now being completely open, and 92L's chances of development during the next 3 days remain near zero. The TUTT to the west will be keeping strong wind shear over the system during most of its passage across the northern Caribbean. Beyond this point, though, 92L will have to be watched very closely. The system will be skirting southern Hispaniola and Cuba on its way WNW, and will eventually end up in the Gulf of Mexico in 5-6 days. At some point 92L will have to actually bust right through the shear zone and pop out on the other side of the TUTT. This is actually a classic setup for mischief, as it has the look of a situation where you get a tropical wave blowing up as it approaches the TUTT, then gets sheared as it goes under it, and then pops out the other side in an area with light shear and favorable ventilation. The western wide of a TUTT is usually conducive for tropical development, and with all the moisture that 92L is carrying with it, this will be something to watch very closely when it gets into the Gulf of Mexico.



Elsewhere....the Atlantic is fairly quiet. A very active ITCZ continues across the central and eastern Atlantic, and has formed several areas of low-mid level turning, along with moderate-strong convection. These areas remain poorly organized, although models are hinting that one of these areas may try to spin up into something substantial within the next 5 days. I believe the concern goes even beyond that, and I don't think we've heard the last of the African wave train this month. I can't remember it ever being this active in June, and with all these disturbances trying to spin up within it, it's only a matter of time before one develops. The upper ridge building into the Caribbean behind 92L will be setting the stage with favorable conditions for development, should one of these tropical waves or disturbances try to lift north and move into the Caribbean. I will be monitoring this area.

The Caribbean, with the exception of 92L, is quiet, although some models are hinting that lowering pressures in the western Caribbean over the next 10 days might try to spark the formation of a low. So far there is no hint of anything significant trying to develop, but the area will be watched once the TUTT lifts out in a few days.

Overall, the pattern continues to get more active, as you can tell a lot of these waves coming off of Africa just want to pop and develop, but most are not being given the proper chance yet, which is normal for June. What isn't normal is having this much activity east of the Caribbean, and this is a big sign of some nasty things we will be seeing coming out of the tropical Atlantic this summer. The MJO is now back over our area of the world, and should remain there through early July, enhancing upward motion in the Atlantic. These last 2 weeks of June and the first couple of July could see the real kick-off to the hurricane season with 2 and perhaps 3 named storms by mid-July.

We shall see what happens!

Invest 92L Visible Satellite (click image for loop):



Invest 92L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Central Atlantic Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 3:49 PM GMT on June 18, 2010

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92L discontinued; A look at possible trouble spots for the next week

By: Levi32, 3:21 PM GMT on June 17, 2010

92L has been discontinued as an invest. The system is now under high shear, and although heavy thunderstorms continue to go off east of the center, it is no longer an imminent threat to develop. The surface circulation has now opened up into a trough, but remains well-defined on visible satellite imagery. The center looks like it will cross the leeward Antilles near Guadeloupe sometime tonight. Thereafter it will continue westward or west-northwestward, possibly tangling with the big islands of Hispaniola and Cuba on its way through the Caribbean. The TUTT is being slower to lift out than was previously forecast by the models, but it will eventually lift to the north and allow upper ridging to build into the Caribbean. This will lower shear over ex-92L a little bit, but due to its northerly track near the islands it will likely remain too high for any development, and the system will have to eventually bust right through the shear zone in order to make it farther west.

Ex-92L is carrying a large amount of moisture with it, and if its circulation remains recognizable during its trek across the Caribbean, it could cause a problem later on in the Gulf of Mexico in 6-8 days. It is hard to say what wind shear will look like in the gulf at this time, as the upper-level forecasts have not been performing perfectly, and wind shear forecasts 6-8 days out are sketchy at best. I do believe the environment will be more favorable than what it will encounter in the Caribbean. When tropical systems bust through the TUTT, they usually encounter favorable conditions on the other side. For this reason, I will be watching 92L's remnants for possible mischief next week. The large amount of moisture associated with the system also means that the Caribbean islands, specifically Hispaniola, could get some heavy rains from this system as it passes by, which is something they don't need right now and will likely get more of this summer.



Elsewhere....the Atlantic is quiet except for an active ITCZ in the central-eastern Atlantic. An area of weak low-mid level turning is evident within the ITCZ near 45W, associated with an 850mb vort max and strong convection. A tropical wave lies behind this feature along 41W. The former, front-running feature looks to be too far south to avoid running right into South America within the next couple days, but this entire portion of the ITCZ is going to be lifting northward over the next few days, and this particular system could end up getting carried into Caribbean waters in several days after crossing part of South America. The wave behind it may also spark the development of a low pressure area, and this feature may have the chance to track farther north and avoid South America. Still behind that another low may form within the ITCZ, which the global models hint at developing into a tropical depression near Trinidad before crossing into the southeast Caribbean in 6-8 days.

While development chances with these features east of the islands are low, upper ridging will be building over the tropical Atlantic and most of the Caribbean over the next week, and therefore atmospheric conditions will be much more favorable for development to occur than they were for 92L, especially if these features get into the western Caribbean later on. When the ITCZ lifts north like this into an area of lowering surface pressures and ridging aloft, you have to watch out. The MJO is starting to move into our area of the world, promoting upward motion over the Atlantic, and the coming weeks will likely see a ramp up in activity that could lead to the real kick-off of the hurricane season as we near the end of this month and head into the first couple weeks of July.

We shall see what happens!

Central Atlantic Visible Satellite (click image for loop):





Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 5:13 PM GMT on June 17, 2010

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92L remains weak, but possible trouble-maker down the road

By: Levi32, 3:30 PM GMT on June 16, 2010

Invest 92L, currently near 15N, 51.5W as of this writing, continues to chug WNW towards the Antilles Islands. 92L put on a very impressive burst of convection last night, forming a nice-looking MCC above the center. This was the burst I was watching for as the system moved over much warmer waters than it was before. However, I expected no significant development with 92L before the islands, and indeed this deep convection has since weakened in recent hours, and is starting to get pushed off to the east of the center by the strong upper-level westerly flow that 92L remains embedded in. Visible satellite imagery this morning also reveals that the surface circulation has likely now opened up into a trough, and is no longer closed. Surface pressures in the area also continue to rise.

I have few changes from yesterday. The 20+ knots of westerly wind shear being inflicted on 92L is courtesy of the TUTT to its northwest, which still lies over the northern Caribbean. An upper-level ridge north of Suriname is building slowly northwestward, and will eventually push the TUTT fully out of the eastern Caribbean by 72 hours, spreading light winds and low wind shear over the area. Whatever is left of 92L will likely not have enough time to take advantage of this short window before shear will increase again as it moves WNW near the big Caribbean islands of Hispaniola and Cuba. My track across the islands between Guadeloupe and Barbuda still looks good, and most of the models have actually shifted south and come in line with that idea this morning, so I have no changes. Moderate convection will likely persist with 92L today due to a diffluent flow aloft over the system, caused by the air streams along the TUTT and the upper ridge north of Suriname parting ways, but I do not expect this convection to be able to organize..

Although I expect no significant development of 92L through its passage of the islands, its remnants could still cause mischief down the road. If 92L remains a recognizable system after crossing the Caribbean islands, it will have to be watched as it moves into the Gulf of Mexico. At this point not much more than speculation can be done with that scenario as it is still 6-8 days out, but with the pattern the way it is, there is concern that if this gets in the gulf as a defined low pressure system or trough, we could be looking at a problem.

Overall, although I believe 92L should have been a tropical depression from Sunday through last night, the chance to be classified appears to be over, and no significant development of the system is expected through the end of this week. However, the leeward Antilles, Puerto Rico, and Hispaniola, may see some heavy rains from this system as it passes by.



Elsewhere....an ITCZ disturbance has formed near 5N, 38W, and is showing pronounced low-mid level turning on satellite and TPW imagery. If this sounds like 92L deja vu, it isn't, as this disturbance will likely not gain enough latitude to avoid running into South America in a few days. Regardless, it will be watched for further development.

To the east of this disturbance lies a tropical wave, which the global models have been trying to develop as it approaches the southeast Caribbean in 6-8 days. Recent runs have backed off some on development, but with these waves trying to come north of South America now and become a problem, it will have to be watched closely.

The overall pattern is about to get ripe for tropical trouble in the Atlantic as we close in on the end of June. Surface pressures will be lowering over the tropical Atlantic during the next 2 weeks as the MJO moves back into our area of the world. The huge ridge over the eastern U.S. means nothing but trouble, not only for heating the SSTs but also because tropical trouble likes to brew south of ridges in the tropics. With the African wave train heating up earlier than usual, we will have to keep a watchful eye out for mischief. I will continue voice concern that the pattern may be getting set to allow the real kick-off of the season to begin here as we near the end of the June and into the first couple weeks of July.

We shall see what happens!

Invest 92L Visible Satellite (click image for loop):



Invest 92L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 3:37 PM GMT on June 16, 2010

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92L to remain weak - potential problem down the road

By: Levi32, 4:20 PM GMT on June 15, 2010

Invest 92L continues to weaken this morning. After moving a bit farther north than expected, the system has encountered moderate wind shear and colder SSTs, both of which are limiting thunderstorm activity to a minimum. 92L is nearing the TUTT, which will continue to increase shear over the system today. The TUTT will be lifting north over the next couple days, but 92L is gaining latitude as well, so it will not be able to avoid all the wind shear. In fact, we very well may see 92L decouple from its upper-level structure sometime today.

Despite this, 92L still has a very well-defined spin at the surface, and as long as it spins like that, it is a potential trouble-maker. 92L is currently at 13N, 45W, still over colder SSTs of 27C with little depth to them. Much warmer and deeper SSTs exist just to the west of the system beyond 46W, and 92L will be moving into that area today. This can be seen in visible satellite imagery. You can tell there is warmer water just to the west because the low-level clouds on that side are trying to rise and become taller cumulus clouds, while the low-level clouds on the east side of 92L are not rising because they are within a stable atmosphere due to colder water. It will be interesting to see if 92L tries to pop some thunderstorms today over the warmer water.



The track forecast appears to need some slight changes this morning. As mentioned above, 92L has moved farther north than expected towards a weakness in the steering rige, and the track models have all shifted north as well in response. Most of them now actually take 92L north of the Caribbean, just grazing the northern islands. While my track will shift north as well, I am still hesitant to take this north of the islands. My track takes 92L over the Leeward Antilles Islands between Guadeloupe and Barbuda, and it will more than likely mess around with Puerto Rico and Hispaniola after that, as I opined yesterday. It should be noted that although this won't be a big deal for the Antilles, the high mountains of Hispaniola could easily turn this into a heavy rain event for them, which is something they may see more of this season.

As far as intensity goes, I expect nothing significant from 92L as it approaches and enters the Caribbean, although it may try another burst of convection over warmer waters. This will likely never get classified now, but I believe it should have been back when it was really going. I have seen far worse systems get classified. This is how the NHC is with storms outside of climatology though.

I will be watching for how well-defined its low-level spin remains, as this system has the potential to still cause trouble down the road. After messing with Puerto Rico and Hispaniola, 92L is bound for either the Bahamas, Florida, or the Gulf of Mexico, or all three. While it will be busting through the subtropical jet on its way there and getting a free haircut, the pattern is such that with the TUTT lifting out and the ridge sitting over the SE US, we will have to watch this very closely if it gets into the gulf in 8-10 days as a still recognizable system.

Elsewhere....showers and thunderstorms in the Bay of Campeche are associated with the old axis of a tropical wave interacting with an upper low. Though this may sit around for a day or two, the wave axis will eventually be moving off to the west, and it takes a lot of time to make a relationship with an upper low work, so development is unlikely here.

A tropical wave along 28W and a wave behind it over western Africa will have to be watched for potential mischief down the road as they near the Caribbean, as the pattern is favorable for these to try to pop like 92L did. These will be passing by farther to the south than 92L, but will curve north upon nearing or entering the Caribbean, and will at least increase rainfall in the eastern Caribbean during the next couple weeks.



This pattern of active tropical waves already trying to develop everywhere bodes very bad for the rest of the season, as it is illustrating for us that the atmosphere wants to deal with this heat and get rid of it, but it can't quite do it yet. It is trying, though, and eventually it will all let loose, which you will see start to happen in July. I will again reiterate that with the MJO coming over and pressures lowering across the tropical Atlantic, the end of this month into the first couple weeks of July is when we are likely to see this season really kick-off.

We shall see what happens!

Invest 92L Visible Satellite (click image for loop):



Invest 92L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 4:39 PM GMT on June 15, 2010

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92L near or at depression status, but struggling

By: Levi32, 5:08 PM GMT on June 14, 2010

Invest 92L, currently near 11N, 40W and moving WNW, continues to be extremely impressive for this time of the year. 92L has become more consolidated since yesterday, and overall has become better organized. Visible satellite imagery reveals a well-defined, closed circulation, which is much tighter than yesterday. A WindSat pass from earlier this morning reveals 25-knot winds north of the center.

In my opinion this system has met the requirements for a tropical depression for some time now, since at least last night, and should have been classified. However, the NHC will remain conservative with these kinds of systems that form outside of climatology, and therefore it is doubtful this will ever get classified.

I say doubtful because 92L does have some problems to deal with now. The system is currently moving over SSTs that are 2C colder than what it was over yesterday, about 27C, and have little depth to them. SSTs and ocean heat content do not increase again until about 46W. A stratocumulus cloud field nearby to the northeast of 92L indicates these colder waters and represents a stable airmass, which occurs over a colder ocean. 92L appears to be struggling with this, evidenced by warming cloud tops over the center in recent hours, and convection has taken on a more ragged appearance. Although these waters are warm enough to support a tropical system, 92L is also struggling with other energy losses, and as a result needs warmer water than this to sustain convection and lower its central pressure.



One of these losses is the fact that 92L has become fully separated from the ITCZ, and has lost the support of its convergence zone. The benefit though is that 92L has finally consolidated into a smaller, more defined system, instead of the broad low that we usually see when it's embedded in the ITCZ. The other energy loss is found in 92L's outflow pattern, which has been severely disrupted on the south side by a weak upper inverted trough to the south of 92L, traveling east to west on the south side of the equatorial ridge. This is preventing air from leaving the system on its south side, and thus ventilation is not nearly as good as it was yesterday.



The forecast now becomes a little more difficult, as we have to figure out whether 92L will overcome all these factors. The system is now much closer to the TUTT, which is close by to the northwest. 92L will be running into this feature over the next couple of days, which will likely add light-moderate wind shear to its problems. However, the upper ridge will be following 92L westward, and will eventually build north and force the TUTT north of the Caribbean, opening up marginally favorable upper conditions again over the system. The farther south 92L travels, the less shear it will encounter. The models are in general agreement that 92L will cross the central-northern Antilles Islands in 4-6 days.

A weakness in the ridge to the north of 92L is currently allowing it to gain lots of latitude, but the ridge will soon build back in and force 92L back towards the west or WNW. I still believe this is going into the Caribbean, not north of it, but it may have to mess around with Puerto Rico or Hispaniola at some point. By this time 92L will have had to fight off several problems, so there is a good chance that this dies and degenerates into an open wave before making it to the Caribbean, but there is also a chance that it survives and remains a defined system. Environmental conditions will be marginally favorable in the Caribbean once 92L gets there, so it will have to be watched whether it has weakened or not. I still give Invest 92L a high chance of becoming a tropical depression, although I think it likely already is, and it remains to be seen if the NHC will classify it or not.

A tropical wave behind 92L has just emerged off of eastern Africa, and will be traveling west along the ITCZ behind 92L over the next several days. The GFS has already been jumping around and causing mischief with this wave down the road as it nears the Caribbean, and although there is no other model support, we have already been surprised once by 92L, and with pressures lowering over the tropical Atlantic during the next 2 weeks as the MJO starts to come over, I will be keeping a close eye on this system, and whatever comes behind it. We are still setting up for what may be the real kick-off to the hurricane season as we near the end of the month and into early July.

We shall see what happens!

Invest 92L Visible Satellite (click image for loop):



Invest 92L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 5:12 PM GMT on June 14, 2010

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Invest 92L Quick Sunday Update

By: Levi32, 2:51 PM GMT on June 13, 2010

The unthinkable appears to be happening. The ITCZ disturbance I have been tracking was declared Invest 92L yesterday, and appears to be on its way to TD status. This is quite frankly shocking, and utterly defies climatology. Having development of a disturbance this healthy way out in the eastern Atlantic at this time of the year is a bad sign for the rest of the season.

92L has been sustaining moderate-strong convection for nearly 24 hours now, and although cloud tops over the center have warmed over the past 6 hours, overall organization remains excellent, with curved banding observed arcing into a well-defined center. Outflow channels are taking shape both equatorward and poleward, and the system is being ventilated nicely by an anticyclone which is forming over top of it. The surface circulation remains elongated to the west, and will take some time to consolidate fully over the next day or so. This is normal for a monsoonal depression, which usually takes some time to organize before ramping up. I say monsoonal depression because 92L developed within the eastern Atlantic monsoon trough, and the system currently has the look of a monsoonal system that we would typically find in the western Pacific. These systems are usually quite large, and take time to spin up, sometimes several days.



The steering forecast was almost made with 92L in mind. A weakness in the subtropical ridge to the north along 45W will allow 92L to take a northerly component to its westward movement and gain latitude over the next couple days. This will help the circulation to consolidate as more coriolis force will be applied. The ridge will then build back in and turn 92L back towards the west, likely right into the Caribbean. This northerly movement will serve to keep 92L away from South America, and this path looks like the best possible track for 92L to develop and survive. A TUTT currently over the central Atlantic is likely to inflict moderate south or southwesterly wind shear over 92L as it travels west, but should 92L continue to develop, it will be dragging an upper anticyclone along with it which will help combat the TUTT, and the TUTT will only be around for a couple days before lifting out of the eastern Caribbean and allowing the equatorial ridge to expand over the area. Although it is yet too soon to speculate on any prospects once inside the Caribbean, 92L would likely have an at least marginally favorable upper-level environment in the Caribbean.

I expect Invest 92L to become this year's first tropical depression, which would make it the earliest tropical cyclone in the eastern Atlantic on record, and should it be named Alex, would be the farthest east a tropical cyclone has ever developed in the Atlantic in June.
Even if 92L does not develop, the mere fact that it exists in this form out in the middle of the Atlantic at this time of year speaks to the dangerous and historic hurricane season that likely lies ahead of us. To get development out of the African wave train this early is unheard of and a very concerning event. The weather is full of surprises. I will have another update on Monday.

We shall see what happens!

Invest 92L Visible Satellite (click image for loop):



Invest 92L Track Models:





Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 2:55 PM GMT on June 13, 2010

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Watching the eastern Atlantic and Caribbean

By: Levi32, 3:46 PM GMT on June 11, 2010

The Atlantic is fairly quiet this morning. Scattered showers and thunderstorms continue to be enhanced over the southwestern and central Caribbean by a divergent flow aloft on the southern flank of the TUTT, as well as a broad surface trough of low pressure in the southwest Caribbean. These thunderstorms have failed to become better organized over the past couple days, and remain mostly benign in nature. A tropical wave traveling across the central Caribbean along 70-72W has weakened within the strong trade wind flow, and very little convection is associated directly with the wave. The wave does remain defined and farther north than any in the Caribbean so far this year, and thus I will keep an eye on it as it interacts with the surface trough in the western Caribbean.



Any system of low pressure that forms would be steered WNW, eventually interacting with central America, which is the biggest limiting factor for potential development. The downward MJO pulse over the Atlantic appears to have limited the heat buildup in the western Caribbean, and as a result there is not as much upper ridging in the area, causing more wind shear over the Caribbean. Upper winds will be relaxing some in the western Caribbean over the next 3 days, but due to lack of convective activity and likely land interaction with central America, I give this area a low chance for development. The area will have to be monitored for the next several days.

Of surprisingly more concern today is an area of low pressure within the ITCZ out in the eastern Atlantic. A broad area of mid-level turning is observed on satellite imagery, though the area is elongated from west to east, typical of ITCZ disturbances. Dry air to the north which has been inhibiting convection is not as pronounced just to the north of the ITCZ as it was yesterday, and thus convection has increased during the past 24 hours. The ECMWF, GFS, CMC, and NOGAPS all hint at development of this area into a defined low or trough over the next few days as it travels west. Development will likely be aided by an AEJ (African Easterly Jet) jetstreak currently moving out over the Atlantic in association with a vigorous tropical wave over western Africa. Such a jetstreak enhances vorticity to the south of it, which may help the ITCZ disturbance spin up. Development way out here at this time of year is unlikely, but due to abnormally warm SSTs and improving upper-level conditions over the next few days, I cannot rule out some mischief. I give the area a low chance of developing into a tropical depression, and it will be monitored closely.



As mentioned above, a vigorous tropical wave is over extreme western Africa, poised to emerge over the Atlantic. Not much convection is associated with the wave this morning, but it remains well-defined, and will have to be watched as it travels across the Atlantic. This wave now appears that it will stay separate from the ITCZ disturbance to its west, and will not be a major player in possible development there. Regardless, this wave and others behind it will be monitored, as these stronger waves are capable of sparking trouble farther west, closer to the Caribbean.

Elsewhere...strong low-mid level turning is observed with a tropical wave along 54W. This wave will be moving westward into South America and is not a threat, though it may generate a few showers in the area of Trinidad in a couple days.

The MJO upward motion pulse will be moving back over the Atlantic in 15-20 days, and the models have been showing lowering pressures in the tropics in about 2 weeks, which is one thing we have been lacking this month for tropical development. As we near the end of the month and head into July, we will likely have to watch for the real kick-off to the season, as the tropical waves will be starting to track farther north with these lowering pressures, and an alleyway towards the Gulf of Mexico or even north of the Caribbean may be possible by that time.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 3:58 PM GMT on June 11, 2010

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The Caribbean and the Eastern Atlantic

By: Levi32, 4:00 PM GMT on June 10, 2010

A broad surface trough of low pressure continues to produce showers and thunderstorms north of Panama this morning, with little change in organization. Our tropical wave that crossed the Windward Antilles Islands yesterday is now along 65-66W, with a negatively-tilted axis that is quite well defined considering the blistering 25-knot trade flow that it is embedded in. Some low-mid level turning is observed on visible satellite imagery just north of the coast of Venezuela. Moderate showers and thunderstorms are associated with the wave, mostly east of the axis due to moderate westerly shear aloft inflicted by the TUTT to the north.



Upper-level conditions will gradually improve over the Caribbean during the next 72 hours, and once west of 75W our tropical wave will have to be watched for mischief as it interacts with the broad area of low pressure in the SW Caribbean. Both features are likely to gradually move WNW during the course of the next several days, and may try to organize either north of Panama or in the Gulf of Honduras. Either way, the low-mid level easterly steering flow will be trying to push any disturbed weather into central America, and land interaction will likely prevent any significant development. Therefore I must give both of these systems a low chance of developing, but with the buildup of heat in the western Caribbean, I will not be taking my eyes off the area.

The other area to watch during the next several days is the eastern Atlantic. Despite being a climatologically unfavorable area for development this time of year, we have a couple of features to watch. One is an ITCZ disturbance that has formed near 31W, moving very slowly westward, with little convection associated with it due to dry air to the north. Turning is evident with this feature on TPW imagery. The other attraction is a massive tropical wave over western Africa, with a very persistent and intense MCC (Mesoscale Convective Complex) moving along with the axis, though this MCC may be starting to dissipate here during the morning hours, which is normal. This wave is quite vigorous, and pronounced turning with the wave is inferred by TPW imagery. This wave will be emerging over the eastern Atlantic within the next 24 hours.



The ECMWF, GFS, CMC, and NOGAPS models are all hinting at a defined low forming in the eastern Atlantic within the next 3-4 days. It is unclear on some of them whether it is the ITCZ disturbance or the tropical wave that they are developing, but since the wave will be catching up to the slower-moving ITCZ low, I am inclined to believe it is some combination of both as they interact.

A strong band of upper westerlies is currently inflicting strong wind shear over the eastern Atlantic down to 12N, but over the next few days this is expected to lift north a bit and allow upper ridging to expand over most of the tropical Atlantic. Unlike most hurricane seasons in the month of June, SSTs are already warm enough to support tropical development, and since upper-level conditions will be favorable, I cannot rule it out based on climatology alone. The area will therefore be monitored for mischief as this vigorous wave and ITCZ disturbance track across the Atlantic.

Elsewhere....everything is quiet. Even if nothing comes of the tropical wave in the eastern Atlantic, it and the waves that follow it will need to be watched down the road once they get into the Caribbean, as that area is still favorable for a buildup of heat that is taking place over the next 10 days, and tropical waves getting into that area will have the potential to cause trouble. The MJO will eventually be coming back over our basin in 2-3 weeks, and by the end of the month into early July is when we could really see this hurricane season kick-off.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 4:05 PM GMT on June 10, 2010

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Watching the Caribbean

By: Levi32, 3:42 PM GMT on June 09, 2010

The Caribbean continues to be the place to watch for the next 10 days. Showers and thunderstorms continue north and south of Panama due to a broad surface trough of low pressure and a tropical wave. Wind shear is fairly light over this area despite the nearby TUTT, and upper-level winds will be becoming more favorable for ventilation of this area over the next 3 days. The interesting thing to notice this morning is that compared to yesterday, the thunderstorm activity has really shifted focus to the east, more in favor of the Atlantic side of things than the east Pacific, which has really diminished in activity west of 85W. This focus of heat more in the SW Caribbean will increase chances of mischief there over the next few days.

I do expect some slow organization of a low pressure area north of Panama during the next 48 hours, but how much development we can get out of it remains questionable. Atmospheric conditions will be quite favorable, but the main hindering factor will be land interaction, as the low-mid level easterly flow due to the high over the Gulf of Mexico is likely to eventually push this area WNW into Nicaragua and Honduras sometime within the next 3 days. The GFS tries to develop the low some more after emerging in the Gulf of Honduras, but the steering flow would probably push this right into the Yucatan Peninsula with little time to sit in the western Caribbean and develop. Thereafter it becomes a question of how strong the ridge over the north gulf coast remains and how far south it steers this feature. The longer it takes for the low to reach the Yucatan, the more chance that this could get into the Bay of Campeche and have some time over water there.

I still don't think we will see much development with this feature north of Panama, and land interaction will be a problem everywhere else, so I will have to give this area a low chance of development, but it should be watched closely over the next several days.



Although the GFS has shifted favorites, and now picks the southwest Caribbean low for development, its old MVP hasn't disappeared. The tropical wave I have been tracking across the Atlantic is approaching the Antilles Islands this morning. This is what the GFS was developing several days ago in the western Caribbean, but instead is now speeding up the timeline and showing development before this wave gets into the area. According to satellite imagery and a WindSat pass this morning, this wave appears to finally be amplifying a bit as it approaches the islands, aided by upper divergence ahead of the TUTT in the eastern Caribbean, which is enhancing a nice area of deep thunderstorms over the wave axis. Although the TUTT may inflict some westerly wind shear on the system for the next 24 hours, it will be starting to lift out and be replaced by an upper ridge over the next couple days, which will provide more favorable upper-level conditions. The eastern Caribbean typically prevents the amplification of tropical waves due to fast trade winds, but it will be interesting to see how well this thing holds together as it passes through the gauntlet.

This wave will be taking a fairly southerly track through the Caribbean, but is the first tropical wave of the year to pass through the Caribbean without being over South America, and this will allow it to be a potential trouble-maker when it gets to the western Caribbean in 4-5 days. How exactly this wave interacts with whatever may be in the western Caribbean when it gets there remains to be seen. It may simply enhance the Panamanian low as it moves towards the Yucatan, or it may try to spark something on its own, or perhaps nothing at all. Regardless, it is a cause for concern as atmospheric conditions will be favorable for possible development, and the buildup of heat over the next 10 days will be centered in the western Caribbean and central America.

Elsewhere....I will still be watching more tropical waves as they come off of Africa during the next couple weeks. Some of these may be vigorous, and the potential for them to cause trouble in the Caribbean will only be increasing as we advance forward during the month. The MJO will eventually be coming back over the Atlantic in 2-3 weeks, and the real kickoff of the hurricane season may be getting set to begin near the end of the month into early July.

Overall, a buildup of heat in the western Caribbean and a tropical wave traveling across into the area in a few days will be monitored for possible mischief. At this time significant development is not expected due to land interaction with central America, but the area deserves attention.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 3:46 PM GMT on June 09, 2010

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Concerns in the Caribbean

By: Levi32, 3:28 PM GMT on June 08, 2010

The Atlantic remains fairly quiet this morning. A broad surface trough in the southwest Caribbean interacting with the monsoon trough is producing showers and thunderstorms north of Panama. A tropical wave over Venezuela will be interacting with this region over the next couple days, and it is possible that a surface low could form somewhere north of Panama. Most of the energy is weighted in the eastern Pacific, where a more pronounced area of low pressure resides, and I believe chances of development on the Caribbean side of Panama with this system are low. This feature will be moving slowly off to the west or WNW over the next few days.



This is the beginning of the buildup of heat I have been watching to begin in the western Caribbean between June 10th and 20th. Initially a lot of this will be focused in the Pacific, but I am continuing to watch a couple of tropical waves, along 60W and 52W, that will be moving into the western Caribbean in several days. The latter wave at 52W will be coming in farther to the north than any wave in the Caribbean so far this year, and with the other waves in front of it piling up air and building the heat, the western Caribbean will have to be watched closely for mischief by this weekend and into next week.

The GFS has backed off on development in this area, although the NOGAPS remains aggressive. No call can be made on this yet, and the situation will simply have to be monitored. The MJO is currently in a downward-motion phase over the Atlantic, which is something against development, but that doesn't make it impossible. Any system that does develop would likely head WNW towards the Yucatan Peninsula and the Gulf of Mexico.

Looking farther ahead, even if nothing develops in the Caribbean next week, there are stronger and stronger tropical waves coming off Africa that will have to be watched as they come across the Atlantic, as they can be trouble farther west. As they start to come off farther north we will also have to start watching for the possibility of a Bertha-type early Cape Verde storm trying to spin up as we get closer to July. The MJO will be in a downward motion phase over the Atlantic for most of the rest of the month, but by the end of the month and into early July the upward motion pulse will return to the Atlantic, and that's when we could really see the kickoff of the hurricane season.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

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Tropical concerns down the road

By: Levi32, 5:07 PM GMT on June 07, 2010

The Atlantic remains quiet for the moment, with no immediate areas to be concerned about for tropical development.

The main features being watched right now are a pair of pronounced tropical waves in the eastern Atlantic. The first one, along 44W, has become less amplified since yesterday, and wind curvature along the axis is very broad. The axis appears to have "jumped" forward a little bit within a broad area of low-mid level vorticity along the ITCZ. An ASCAT pass from just a few hours ago shows this broadness well.



This wave continues to be no immediate threat this far out in the Atlantic, but over the next few days it will be moving WNW, eventually trying to detach from the ITCZ as it crosses the islands likely at the northernmost latitude of any wave so far this year. The wave will then proceed towards the western Caribbean, where it will be moving into an area of building heat in 7-9 days. This is illustrated by the GFS ensembles, which show high amounts of precipitation falling in the western Caribbean by day 9. This buildup of heat is occurring due to a new round of tropical waves piling up air in the area, as well as an active monsoon trough that may try to lift north into the area.

The GFS has been on and off with development in the western Caribbean, and it remains to be seen whether something will try to spin up before the wave gets there, or if the wave itself will be the catalyst for development. Regardless, I am concerned about this area due to the buildup of heat going on between June 10th and June 20th, and should any development occur, a system in that area would be likely to move into the Gulf of Mexico.



The other tropical wave of interest has just emerged off of the African coast, and has a nicely-defined axis. Dry air may inhibit convective development of this wave, and unlike its predecessor, the models seem to expect this wave to say to the south within the ITCZ as it crosses the Atlantic. This is still to be expected as tropical waves do not develop east of the islands at this time of year, mostly due to their latitude. This wave, however, and those behind it, are still a concern, as the buildup of heat will be continuing in the western Caribbean, and when these waves get west, they can cause mischief.

Overall, there are no immediate threats in the tropical Atlantic, but a tropical wave moving into an area of building heat in the western Caribbean next week could try to cause mischief, and such mischief could have an alleyway into the Gulf of Mexico.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 5:09 PM GMT on June 07, 2010

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Quick Sunday Update

By: Levi32, 4:55 PM GMT on June 06, 2010

The Atlantic remains fairly quiet. The system I have been watching over the western Gulf of Mexico continues to look rather tame. There are now thunderstorms going off with a weak vort max south of Louisiana, but the main piece of this energy split off to the west while it was in the Bay of Campeche, and so there is not much to this system. While I will watch it because these vort maxes can be mischievous at a fast pace, I do not expect development.

The main topic for the next week will be a tropical wave currently along 33W, which has the mark of a trouble-maker down the road in the Caribbean. I have been voicing the concern for a buildup of heat in the western Caribbean during the period of June 10th to June 20th, and the potential for mischief in that area. This tropical wave could be our first chance at that, as it is forecasted to lift northward and become independent of the ITCZ, crossing the Antilles Islands in 4-5 days. As this moves into the western Caribbean in 7-10 days, it will have to be watched closely as it interacts with the buildup of heat that will be occurring in the region ahead of it, and the TUTT may be in a position to ventilate the area.

Another wave is about to emerge Africa as expected, and this one also has a very well-defined signature. The models don't do much with this wave and keep it pretty far to the south, but these things don't develop out in the middle of the Atlantic in June anyway. When they have to be watched is when they get across into the western Caribbean and start piling up air in that area.



There is dry air to the north of these waves, but no African dust to speak of. This is courtesy of the negative NAO we had this winter, reducing the easterly winds blowing dust off of Africa. The MJO will be mostly in its downward phase over the Atlantic for the next couple weeks, which may make it harder for something to get going, but not nearly as hard as it was last year. Overall, we have an impressive wave to watch as it tracks across the Atlantic, and although development is not expected east of the islands, it could be a trouble-maker down the road in the Caribbean.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

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Quick Saturday Update

By: Levi32, 3:30 PM GMT on June 05, 2010

The Atlantic is quiet. A piece of mid-level energy moved into central America last night and is now entering the very southern Bay of Campeche. So far this doesn't look too impressive, and wind shear is currently high over the western gulf, but I will be keeping an eye on it over the next couple days in case it tries to stir up anything with the upper low backing away over Texas.

A powerful tropical wave over western Africa will be emerging over the Atlantic in a couple of days. This wave is likely to be the strongest yet of the season. It can be easily seen as a very pronounced kink in the African Easterly Jet at 650mb along 5W.



There is also a nice vorticity max along the wave axis.



Nothing much is expected from this wave development-wise as it tracks across the central-eastern Atlantic, but it is these stronger waves starting to come off that will be starting to pile into the western Caribbean in about a week's time. This will cause a buildup of heat around central America and the western Caribbean, and I would watch this area during the June 10th to June 20th period, as it is possible we may see some mischief out of this pattern.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 3:30 PM GMT on June 05, 2010

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Tropical Tidbit for Friday, June 4th

By: Levi32, 3:36 PM GMT on June 04, 2010

The tropical Atlantic remains pretty quiet this morning. Little thunderstorm activity is observed in the MDR, and very nice, sunny conditions are found in the central Caribbean due to a convergent flow aloft.

An area of disturbed weather south of Bermuda associated with an upper shortwave and a surface low is not likely to develop.



There is one specific area that may peak some interest during the next few days. An upper trough over the northwest Gulf of Mexico is becoming cut-off from the main westerlies, and will be sitting in the region for a few days. Beneath this trough lies a vigorous surface circulation over land near the TX/LA border, which is the remnants of an old MCV (Mesoscale Convective Vortex). This system will not be moving over water, and will be taking off to the northeast with a piece of the upper trough, while the tail-piece gets left behind over the gulf. This trough will be drawing a piece of energy from the Pacific, currently south of Guatemala, across central America and into the Bay of Campeche over the next couple days. Although upper-level winds may be unfavorable and the models don't expect this energy to be very strong, it is a situation that could cause mischief and thus it will be monitored.



The African wave train remains fairly active. Dry, Saharan air over the eastern Atlantic has collapsed most of the convection associated with the wave which came off of Africa 2 days ago, but there is a well-defined spin along its axis and popcorn convection is going off again. This wave is not expected to be a threat as it travels across the central-eastern Atlantic. A powerful tropical wave moving across western Africa will be emerging in the Atlantic in 2-3 days. This wave is coming off slightly farther north than its predecessors, and could potentially be a trouble-maker down the road when it gets west into the Caribbean.

None of these waves are expected to be a real threat in the central-eastern Atlantic, but some of these stronger waves could mean business when they get across into the Caribbean, and it is likely that there will be a buildup of heat near central America and the western Caribbean between June 10th and 20th as these waves pile up air in this area. This will continue to be the area to watch if we're going to get our first named storm this month.

With the MJO moving away and large-scale downward motion expected to move in by the 15th, it may be hard to get something going, but by the end of the month and into early July the MJO upward motion pulse will be moving back into our area of the world, and that is when the season may really kick off.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

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The Gulf, the Pacific, and African Waves

By: Levi32, 4:06 PM GMT on June 03, 2010

The Atlantic remains fairly quiet this morning. There is an area of disturbed weather east of the Bahamas associated with a weak surface low and upper disturbance. This feature will be meandering slowly off to the east and north over the next few days and will be watched, but development is unlikely.

A very intriguing feature is taking shape over Texas this morning. Last night a massive blowup of convection turned into an MCS (Mesoscale Convective System) over central Texas, and as is typical with such systems, that convection is dying off this morning. Sometimes MCSs are strong enough to form their own circulation underneath, and at that point they become MCVs (Mesoscale Convective Vortex). This system appears to have been an MCV as the dying thunderstorms this morning are revealing a vigorous circulation and surface low WNW of Houston. This system is associated with an upper shortwave trough that is becoming cut-off from the main westerlies, and will be meandering around the Texas coast for the next few days. Should this old MCV move over the water of the northwest gulf, it may try to cause tropical trouble.





Another area I am watching is the eastern Pacific, which actually ties in with the Texas MCV. The area of disturbed weather west of Costa Rica that I have been monitoring is slowly organizing, and has some nice mid-level rotation with it. This feature may try to develop over the next couple days, but what is even more interesting is that a deep-layer high building into the Caribbean over the next few days may steer this energy northwestward into Central America, and possibly across into the Bay of Campeche. Interestingly enough, our MCV may still be sitting in that area during that time, and it will be interesting to see what comes of this.



Elsewhere...the African wave train is still being watched. Dry air is killing convection with the tropical wave south of the Cape Verde Islands, and it appears the axis may have reformed to the east, but it is hard to tell. Regardless, this wave poses no threat for development out in the Atlantic and will continue westward. Two more waves, One over Nigeria and the other over Sudan, are continuing westward across Africa, and will be emerging over the Atlantic within the next two weeks. These waves are a bit farther north than their predecessors, and although we are unlikely to see anything particularly threatening from them out over the Atlantic, they may cause trouble in the Caribbean down the road. Thus, they will continue to be tracked and monitored.



Cyclone Phet, as expected, has weakened on its approach to Oman, and did not become a Cat 5. Dry air entrainment has weakened the storm to what looks like a Cat 2, and this is very good news for Oman, which will see much less of a storm at landfall than what was advertised. Rain will be the biggest problem with this system as it slowly recurves over eastern Oman during the next couple days.

We shall see what happens!


Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 4:30 PM GMT on June 03, 2010

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Tropical Tidbit for Wednesday, June 2nd

By: Levi32, 3:33 PM GMT on June 02, 2010

Things are fairly quiet in the Atlantic this morning. Invest 91L has become too ill-defined to sustain any kind of convection, and has vanished off of satellite imagery, as well as the surface maps. Two tropical waves, one west of Costa Rica and the other lying across Panama, are sparking scattered showers and thunderstorms across the far eastern Pacific and southwest Caribbean. An area of broad mid-level turning is observed with this area on satellite imagery south of Costa Rica. Convection is currently disorganized, but this feature may try to spin something up in the eastern Pacific, and will be monitored. the NOGAPS, which was previously forecasting development in the SW Caribbean with the wave over Panama, has backed off, and although convection will continue north of Panama, I believe the system does not have enough time to generate something in this area, especially with competing energy on the Pacific side.



A rather impressive-looking tropical wave has just emerged off the west coast of Africa overnight, and is located along 17W. A good amount of consolidated convection is associated with this wave. Slight mid-level turning is observed on satellite imagery, but the wave looks to be too close to the equator to try to develop a circulation. Another tropical wave, located along 14E over central Africa, maintains a defined signature, but only has scattered and disorganized convection is associated with it. This wave will be emerging into the Atlantic in 4-5 days. Both of these waves will likely remain too far south to pose any kind of a development threat in the central-eastern Atlantic, but such features deserve to be tracked as they have the potential to spawn trouble if they get into the Caribbean down the road.



Also seen on the image above is Cyclone Phet, a powerful and dangerous Category 4 cyclone with 145mph sustained winds, approaching the Arabian Peninsula. Such a powerful storm in the Arabian Sea is rare, especially so close to the Arabian Desert. Cyclone Phet is forecasted to become a Category 5 as it makes landfall in eastern Oman sometime in the next 24-36 hours. I personally find it hard to believe that this will become a Cat 5, based on satellite presentation and surrounding conditions, but a major cyclone of any kind could be devastating for the region.

With the downward pulse of the MJO starting to come across and the lack of foreseeable disturbances, tropical development is not expected in the Atlantic for the next 5 days. However, the next two weeks will see the overall pattern being favorable for mischief in the western Caribbean with dominant upper ridging, providing low wind shear. The mean trough south of the Canadian Maritimes will also be in a position to ventilate the Caribbean over the next 10 days, so this will be the area to watch if any disturbance gets in there.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

Updated: 3:38 PM GMT on June 02, 2010

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The Atlantic Hurricane Season Begins

By: Levi32, 3:50 PM GMT on June 01, 2010

Today marks the first day of the Atlantic hurricane season, and of what promises to be a hard summer for many. So far in the first hour all is well in the Atlantic, with no areas of significant concern.

The one area still catching attention is the western Caribbean, where the remnants of Tropical Storm Agatha, after playing dead with us last night, have come to life once again. A new circular burst of convection has blown up since 8z this morning northeast of Belize, stronger than yesterday's, and unlike yesterday's is stationary, not moving much. The problem is that conditions are not that favorable for tropical development. Ex-Agatha is lying on the periphery of an upper ridge over the Caribbean, and the subtropical jet is racing by just to the north. This is resulting in 10-20 knots of westerly wind shear over the system, which yesterday was responsible for decoupling the system. This wind shear is also trying to punch in dry air from the west. Visible satellite indicates no well-defined low center in the area, and indeed although a low is still present on surface maps, it has weakened to 1012mb as pressures in the area rise. Due to these factors, this MCS (Mesoscale Convective System) will have to fend for itself and form its own circulation, which will be hard to accomplish unless convection can persist strongly for another 6+ hours. Very light NNW winds are being observed in Belize, indicating that a surface trough is still present, but it is weak. Based on these factors, and the fact that a similar burst fell apart yesterday, I give Agatha's remnants a low chance of developing into a tropical depression. I will be watching for persistence today to see if any changes are warranted.



Elsewhere....a tropical wave along 77W interacting with the monsoon trough is sparking showers and thunderstorms north of Panama. Weak low-mid level rotation is observed with this feature, and the tropical wave will continue westward into the eastern Pacific over the next couple days. The NOGAPS model has been consistently forecasting the next wave behind it, currently over NW venezuela, to form an area of low pressure on the Caribbean side of Panama in a couple days and strengthen it. The GFS also shows development but in the eastern Pacific instead. Typically in these situations the east Pacific is more favored for development, but the situation will be monitored. If a disturbance does form north of Panama, dominant steering currents would take it WNW into central America, which would likely disrupt any development.

A well-defined tropical wave over central Africa along 18E continues to be tracked as it moves across the continent. This wave will be emerging over the Atlantic in 5-7 days, and may prove and interesting feature to track across the basin for the following week.

The upward motion pulse of the MJO that has been over the western Atlantic is now starting to move off to the east, and more of a large-scale sinking pattern is set to move back into the Atlantic over the next couple weeks. I do not expect this to be horridly strong, but it will likely suppress convection for a lot of the month, and make early development less likely. The next upward motion burst will come near the end of the month and into early July, when I think the real deal will begin. However, I cannot rule out development this month, as the Caribbean will be generally favorable for mischief should a tropical disturbance move into the area.

We shall see what happens!

Caribbean/East Pacific Visible Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



200mb Vertical Velocity (green areas represent upward motion associated with the MJO):








2010 Atlantic Hurricane Season Outlook

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About Levi32

Levi Cowan has been tracking tropical systems since 2002, and is currently working on his bachelor's degree in physics at UAF.

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