Tropical Tidbits from the Tundra

Watching Ex-90L: still a threat down the road

By: Levi32, 5:14 PM GMT on July 31, 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. If HD quality isn't available, then it will be in a few minutes. Let me know if you have problems or questions about the video.



The Atlantic remains fairly quiet today. A tropical wave moving through the central Caribbean is losing convection due to the strong trade wind flow but will have to be watched for possible mischief in the western or southwestern Caribbean in a couple days under a ventilated environment. The place to watch will be north of Panama.

Invest 90L has now been deactivated, which is slightly puzzling to me given that it hasn't disappeared and looks better than yesterday, but with embedded lows in the ITCZ I suppose it could be considered prudent. However, don't let your guard down on this system because of that. As mentioned, visible satellite imagery indicates a well-defined low-level circulation and increased convection with the system near 35W, and it's back down at 8N now which may limit its development due to lack of the Coriolis effect, but it will be gaining latitude over the next several days.

The fact that it's embedded in the ITCZ will mean this will continue to be a slow developer with only gradual organization expected over the next few days. I mentioned that we would not be seeing a depression out of this anytime soon, and just because it hasn't developed yet doesn't mean that the threat is over. Ex-90L will be continuing to move only slowly westward at a crawl over the next day or two. A tropical wave behind ex-90L is catching up and bringing in a mid-level circulation, and we'll have to see how these two interact over the next few days. My feeling is that ex-90L will remain the dominant feature and will absorb the incoming wave from behind, not the other way around.

This conglomeration of convection will accelerate WNW in a couple days and should end up near the northern Antilles in 5-6 days. Interests in the Antilles, Virgin Islands, and Puerto Rico should monitor the progress of this system. Beyond this point the track remains unknown, but I still don't believe this is recurving way out to the east and it could threaten the southeast United States down the road. Recurvature is still a possibility that is on the table once it gets west of 75W, but by that point it will already be affecting somebody. Whether it affecting somebody as a tropical wave or a tropical cyclone, we still don't know for sure, but I do believe this has a decent shot at eventually developing, and should be watched closely for a possible long-range threat to the SE US, and now a medium-range threat to the Caribbean islands.

Overall, I continue to give ex-90L a low chance of developing into a tropical depression during the next 2 days, and a moderate-high chance of ultimately developing at some point.

We shall see what happens!

Invest 90L Visible/IR2 Satellite (click image for loop):




Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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








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Updated: 5:23 PM GMT on July 31, 2010

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90L currently disorganized, but a potential threat down the road

By: Levi32, 4:31 PM GMT on July 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. If HD quality isn't available, then it will be in a few minutes. Let me know if you have problems or questions about the video.



Several features are notable in the Atlantic today. A 2nd front coming down off the SE US and near Bermuda will be monitored any development of low pressure over the next couple days, and although this doesn't look like a significant threat, stalled fronts can be sneaky and should always be watched for home-grown mischief.

A tropical wave in the western Caribbean is entering a favorable environment but it is not very amplified and will move into central America without developing much. Another tropical wave generating widespread convection in the eastern Caribbean is associated with a large and elongated area of cyclonic turning which will have to be watched for possible mischief when it gets into the western Caribbean in a few days and gets ventilated by the TUTT.

Invest 90L continues to be the biggest story and is still sitting out in the eastern Atlantic near 32W. The system is maintaining a well-defined low-mid level circulation but has lost a lot of convection, and is suffering from being embedded in the ITCZ. As expected this is making very little progress westward and will continue to move slowly over the next couple of days before accelerating WNW after the weekend. This should end up in the vicinity of the northern Antilles in 6-7 days.

As for whether this develops, it's still not a given that it will, although it still appears to have a decent shot at it. A big tropical wave coming off Africa behind 90L may try to merge with the system over the next few days while it is stalled, allowing the other wave to catch up from behind. This other wave may end up being the real catalyst for development, but either way any development of 90L will be slow and gradual over the next few days until it can get free of the ITCZ. After that, if it develops, my feeling is that it would be likely to strengthen, and could be a threat to land farther west. I don't think this is recurving. Ridging is once again looking to become dominant over the eastern US and with the MJO getting ready to return to the Atlantic soon this pattern is supported. The models will continue to flop around on this. The ECMWF is actually having an abnormally tough time resolving the upper pattern over the next 10 days, and thus we must use more common sense and good old-fashioned forecasting with this system for now.

Overall, I give 90L a low chance of developing into a tropical depression during the next 2 days, with a moderate-high chance of ever developing. Right now this is still nearly a week away from threatening the Caribbean and even farther than that from potentially threatening the United States, so we will just keep an eye on this system for a possible long-range threat.

We shall see what happens!

Invest 90L Visible/IR2 Satellite (click image for loop):



Invest 90L Track Models:




Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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








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Updated: 5:16 PM GMT on July 31, 2010

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Watching the east Atlantic and Caribbean; Tropics still mostly quiet

By: Levi32, 5:06 PM GMT on July 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. If HD quality isn't available, then it will be in a few minutes. Let me know if you have problems or questions about the video.



Please bear with me in the video....I'm a bit tired this morning.

The Atlantic remains mostly quiet this morning, though convection has increased overall in the tropics. This is a sign of the MJO starting to turn around and march back towards our area of the world, and the overall trend of convective activity should be on the increase over the next couple weeks. A tropical wave in the central Caribbean is not a threat to develop as it has been deamplified by the strong trade wind flow through there. A tropical wave near 55W is associated with a broad area of cyclonic turning stretched out across the entire central Atlantic, and convection is blowing up near and west of the wave as it moves into a more ventilated area under upper ridging in the eastern Caribbean. This area may need to be monitored for possible mischief once it gets into the western Caribbean in a few days, where surface pressures are forecasted to lower.

The biggest story will be the system in the eastern Atlantic, now near 30W, which remains well-defined this morning. Low-mid level turning is very evident on visible satellite imagery, and strong convection continues to be associated with the system, mostly west of the center. This system has lost some latitude since yesterday and has gone from 11N to 8N, putting it more embedded within the ITCZ, which will likely limit development for now. However, it is moving into an area of net cyclonic circulation and non-existent trade winds that will result in very slow movement of the system and a favorable environment for an embryonic system to develop. Expect some but little westward progress of the system over the next 3 days.

Next week the system will begin increasing in speed towards the WNW under a stronger steering flow, and we will have to see how it looks by then, but this may take some time to organize. The pattern so far this year is for these things to wait until they are further west to blow up, and the models are hinting at the same thing here. The ECMWF 0z is back onboard and develops this south of Bermuda in 7-10 days. It looks like it's going to recurve the system out to sea but at the end of the run turns it back west as ridging builds into the eastern United States. Specifics of the model run in the long-range cannot be trusted. Remember just yesterday the Euro had this in the Caribbean, but I will just mention that the MJO coming back into our area of the world would favor ridging returning to the eastern US, and that would tend to steer things west, but it's too far out to say right now what might happen with this system. The GFS remains unimpressed and keeps this an open wave when it passes north of the Caribbean, but keeps it well-defined and definitely not something that will just fizzle.

The same run of the GFS is continuing to show amazingly low pressures in the tropics in the 10-15 day period, getting everything south of 15N below 1010mb by the end of the run. That is 4-5mb below normal for this time of year, and is hinting at the pattern we are heading into for the heart of the hurricane season. Low pressures in the tropics mean heat that is being lifted, and so the model is showing us the tendency for heat and upward motion to be focused in our area of the world.

Elsewhere....there are no immediate threats for tropical development during the next 2 days. We will continue to watch for Colin to show himself.

We shall see what happens!

Invest 90L Track Models:




Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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








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Updated: 7:13 PM GMT on July 29, 2010

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First Cape Verde storm looming?

By: Levi32, 4:25 PM GMT on July 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. If HD quality isn't available, then it will be in a few minutes. Let me know if you have problems or questions about the video.



The majority of the Atlantic remains quiet today. An old front stalled off the SE US tried to form an area of weak low pressure but as expected this is not a significant threat and shouldn't be a problem for tropical development. A 2nd front drops down later on this weekend and will be monitored.

A tropical wave now in the eastern Caribbean is feeling the effects of the strong trade wind flow in that area and is less amplified than yesterday and has lost convection. However, once in the western Caribbean, this may have to be watched as it will be in a nicely-ventilated environment with an upper low backing away to the west. Either way, this will head west into central America and the southern Bay of Campeche and will likely be just a rain event for that area.

A couple of tropical waves in the central Atlantic have sort of merged into a very large and elongated cyclonic circulation of low pressure that is traveling slowly westward, and will end up in the Caribbean in a few days. This may also have to be watched if it is able to be ventilated, as large cyclonic circulations in the Caribbean can be very mischievous.

Now, a tropical wave that has a chance to be a big deal down the road is roaring loudly in the eastern Atlantic right now south of the Cape Verde Islands along 22W. This wave is the first one of the year to show a significant increase in convection more than 24 hours after emerging off the African coast, and this one has the mark of a trouble-maker. Very well-defined mid-level rotation was observed on visible satellite imagery this morning, and a 9-hour old Windsat pass from earlier this morning showed a circulation trying to form in the low-levels. This wave has some dry air coming off with it but that is often a sign of a strong wave, and this dry air does not have nearly as much punch to it as previous bursts that completely dried up the preceding waves, and thus it shouldn't be as much of a problem for this one.

It would be wise to be cautious with this wave as these things have a tendency to fall apart on you even when they look perfect, but to me this looks like it could mean business. Although it could possibly take several days for this to try to organize, I would not be surprised to see this labeled an invest sometime within the next couple days if it maintains current organization and convection. Honestly, if the WindSat pass this morning was accurate, this wave is only one small hop away from a tropical depression. As with most things though, we will want consistency of such a presentation before leaping to conclusions.

This wave will be moving very slowly westward over the next 5 days, an indication of the slow trade winds which can allow waves like this to amplify and form surface lows. The ECMWF 0z run last night developed this into a tropical cyclone in the eastern Caribbean in 10 days, and the old GFS 6z run this morning also developed this as well as two other waves behind it, forming a parade of 3 storms on the map in 10 days. A 4th storm developed by the end of the run, resulting in 3 tropical cyclones on the model between Day 10 and Day 15 nonstop. This was the final model cycle ever to be run by what we've known as the GFS, and it went out with quite a bang. At 12z this morning the GFS was replaced by an upgraded version with higher resolution, based off of the parallel model that we have been using. The 6z run of the new GFS is not as impressed with this wave but does form an area of low pressure with it as it approaches the islands. The CMC blows up this wave in a few days which is expected of that model. It will be interesting to see if today's runs continue to see this wave.

Overall, the Atlantic is still quiet to close out July but will not remain that way very long into August. I show on today's video how the GFS is finally sniffing out where it's supposed to be on the MJO forecast, and my idea that it would change its forecast proved to be correct. Upward motion should return to the Atlantic during the next couple weeks, and with the upper pattern maturing into one that can support multiple named storms on the map at the same time, we will have to start keeping our eyes wide open for things to start popping. This wave in the eastern Atlantic just might be our first Cape Verde-type development, and will be monitored closely.

We shall see what happens!


Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






Updated: 4:28 PM GMT on July 28, 2010

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Atlantic quiet for now, but getting ready to light up

By: Levi32, 5:04 PM GMT on July 27, 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. If HD quality isn't available, then it will be in a few minutes. Let me know if you have problems or questions about the video.



The tropical Atlantic remains mostly quiet today. The little devil of a wave that has been being watched is now across the Yucatan and into the Bay of Campeche, but is now more spread out and the loss of convection over land has made it lose most of the upper ridging over it. This will be another rainmaker for Mexico and SE Texas, but as expected, will not develop before landfall.

The first front dropping down off the SE US coast today is sparking thunderstorms off the Carolinas underneath the nose of the upper ridge which illustrates the things we have to watch for when these fronts get stalled over warm water, but this doesn't look like a significant threat to me, although the area will be monitored. A 2nd front coming down this weekend and into early next week will also have to be watched for homegrown mischief, but so far there are no threatening looks to any of the computer models.

A tropical wave along 58-60W approaching the Antilles Islands will have to be watched as it comes west into the western Caribbean in 3-4 days. Upper ridging is building into the Caribbean with this system, and the upper low to the west will be backing away while what's left of the TUTT forms a 2nd cut-off low to the east. The result is an upper ridge sitting over the western Caribbean in 3 days with upper lows on either side of it ventilating the area and providing outflow jets. This is a nice situation for this little wave to try to develop, and although it could be hard to pull off with the current large-scale downward motion of the MJO, it's worth watching. Such a system would be directed west and away from the United States, but could be a problem for Mexico. The rapid westward movement could also be a point against development, but the area will be monitored.

A couple more tropical waves out in the eastern Atlantic will continue to be watched as well as they come farther west, and perhaps get a chance to fire up some convection later on. These are similar to Bonnie in structure and satellite presentation, so don't take your eyes off them.

Elsewhere....there are no immediate threats for tropical development during the next 2 days. The video shows why the models are hinting at a very lucrative pattern for development taking shape in a couple weeks.

We shall see what happens!


Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






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Little Devil being watched, otherwise quiet in the Atlantic

By: Levi32, 5:20 PM GMT on July 26, 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. If HD quality isn't available, then it will be in a few minutes. Let me know if you have problems or questions about the video.



The tropical Atlantic remains mostly quiet today. The MJO is taking a little vacation from our area of the world and thus dry air and sinking air dominate most of our basin. A well-defined tropical wave moving west of the Cape Verde Islands will be watched later this week for a possible increase in convection as it gets farther west, possibly similar to what happened to Bonnie's wave when it got farther west. A front dropping down off the SE US coast this weekend will be watched for possible home-grown mischief as the front stalls and remains draped across the area for a few days. Weak low pressure may try to form between the east coast and Bermuda, as well as possibly the northern gulf, and with SSTs well-above normal off the eastern seaboard, this situation will have to be monitored, but is still several days away.

The sneaky little devil of a tropical wave that has been trekking westward across the Caribbean has developed a very pronounced inverted-V signature along the east coast of the Yucatan Peninsula this morning, which is confirmed by the weak NE winds being reported out of Belize for the past few hours. A strong 850mb vorticity max has developed near the coast, corresponding to the sharp wave axis observed on satellite imagery. Radar out of Belize shows a broad area of weak low-mid level turning associated with the wave axis. Winds out of Costa Maya, east of Chetumel, Mexico this morning have been sustained from the southeast at 25-30mph with gusts over 40mph for several hours now, indicating that this is a vigorous tropical wave.

If this were not moving inland over the Yucatan today I would be more concerned about development, but as it stands I still don't expect a tropical cyclone out of this. However, this should be watched carefully for any further organization once it emerges over the Bay of Campeche. The wave is nestled in a marginally favorable upper-level environment south of a weakening upper low over the Gulf of Mexico which is now ventilating it. Weak upper ridging is developing over the wave and the beginnings of outflow can be seen on water vapor imagery. This wave is the same sneaky little devil that was holding on to Bonnie's skirts back in the eastern Caribbean when the two were nearly inseparable, and it has put up a nice fight all the way across the Caribbean and has now developed into a nice little system moving into the Yucatan. This will continue across and WNW across the Gulf of Mexico towards northern Mexico. This will be yet another tropical system making a run at the west gulf coast, and another shot of rain for areas that don't need any more.

Elsewhere....the Atlantic remains quiet, and we should see a fairly quiet period continue over the next 10 days or so to close out July and introduce August, which promises to get very busy later on.

We shall see what happens!


Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






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Rest of July quiet, But don't let your guard down

By: Levi32, 4:31 PM GMT on July 25, 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. If HD quality isn't available, then it will be in a few minutes. Let me know if you have problems or questions about the video.



The tropical Atlantic remains fairly quiet, with no significant threat areas for development during this final week of July. A weak trough of low pressure in the western Bay of Campeche is moving inland and bringing yet more rain to eastern Mexico. A large tropical wave in the western Caribbean is interacting with an upper low and has a couple of mid-level rotation centers along its axis, but is not a big threat to develop and will just be a rainmaker for central America and the western Caribbean islands as it propagates slowly WNW over the next few days.

A large tropical wave moving off the African coast will have little convection with it on its journey across the eastern Atlantic, but it will have to be watched once it comes farther west to see if it can acquire some convection like Bonnie did. This is a well-defined feature that will be tracked closely. A couple of fronts diving down off the SE US coast and near Bermuda over the next 10 days will have to be watched for homegrown mischief as they stall and weak low pressure tried to develop along the front. The first front comes in on Tuesday or Wednesday, and another one may get stuck in the area later next weekend into early next week. Potential for development looks low right now, but the situation will be watched.

Overall, the rest of July looks likely to be quiet, but we are still ahead of a climatologically normal hurricane season and no one should let their guard down.

The video today details why we should still be very concerned about what the heart of the hurricane season holds in store for us here in the Atlantic, and why the GFS is in lala land with the MJO. Large-scale upward motion should return to the Atlantic by the 2nd week of August, and by mid-month we should see the kick-off to one heck of a storm train that may not stop until October or even November. 'Tis true, this is a bold forecast, but this year has the potential to be a historic impact year on the US and Caribbean countries. Although total named storm numbers won't top records like 2005, with the majority of them being directed towards land, the total impact of the season when it's all said and done may rank among the worst. All I can say is that I hope you're ready.

We shall see what happens!


Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






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Bonnie dead; On the hunt for more tropical trouble

By: Levi32, 3:46 PM GMT on July 24, 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. If HD quality isn't available, then it will be in a few minutes.



What's left of Bonnie is moving WNW towards Louisiana near or east of the river and will be just a tropical rainy day for the north gulf coast. This is a 1015mb tropical low, certainly a common event in the gulf and not a threat. The oil spill area isn't even experiencing winds much higher than a normal trade wind flow. This will be inland this evening.

Elsewhere....The disturbance tangling with the Caribbean islands has finally been recognized for what it is, a tropical wave, and now that the NHC is paying attention, they are mentioning it in the tropical weather outlook. We of course already knew what this was and that it was something to watch. The wave is being very intimate with an upper low right now, so the environment isn't that great for development, but if it keeps firing thunderstorms we'll have to watch for it to warm the environment aloft and try to cause mischief as it heads west towards the gulf. Right now this isn't an immediate or significant threat except for more heavy rainfall for Hispaniola, Jamaica, and Cuba. The system will be monitored.

There are no other areas of interest except for an area of convection in the very SW Bay of Campeche due to upper divergence from the upper low to the north and possibly some remnant piece of 98L. While there is some low-mid level turning with this, it should be forced inland before having a chance to feedback.

Another train of strong tropical waves are poised to leave Africa, and although dry air over the eastern Atlantic has not been providing a very conducive environment for development, these have to be watched as they come west into the much more moist SW Atlantic. Remember Bonnie was a naked wave out in the eastern Atlantic but as soon as she approached the Caribbean islands she blew up. Such is the pattern to be concerned about if these waves wait until they are farther west to pop, and by that time they are a threat to every country in the western Atlantic.

The MJO is taking a short leave of absence from the Atlantic, though it will not be as strong nor as long as the GFS claims. By the 2nd week of August this should be coming back around to the Atlantic where it belongs, and upward motion will never really leave the eastern Atlantic and Africa, and thus we will have to keep an eye out for Cape Verde development over the next couple weeks, and the GFS Parallel is already hinting at that.

Also worthy of watching are a couple of fronts that will be draped off the SE US coast over the next couple weeks, one in about 5 days and another in about 10 days. Both of these should be monitored for possible homegrown mischief along the front as an upper ridge noses over the area, and in such a situation you can get little warm-core lows to develop along the frontal boundary. The 2nd front coming during the first week of August appears to be the better chance of the two at spawning mischief, so the area will be monitored.

Overall, we're back to fairly quiet in the Atlantic, but it will not remain that way for long. Enjoy it while it lasts. Remember we are still ahead of a normal season with 2 named storms and we could easily have 4 if TD 2 and Invest 92L had been named.

We shall see what happens!

Rainstorm Bonnie Visible/IR2 Satellite (click image for loop):



Rainstorm Bonnie Track Models:




Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






Updated: 3:50 PM GMT on July 24, 2010

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TS Bonnie makes landfall; Possible home-grown mischief next week?

By: Levi32, 4:40 PM GMT on July 23, 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. If HD quality isn't available, then it will be in a few minutes.

I apologize some of the graphics got downsized a bit in this video, so a couple of them might be a little hard to see in detail.



Tropical Storm Bonnie has made landfall in Florida, south of Miami this morning. The worst of the weather is out ahead of the center and is already inland, with not much coming in behind the center. Easterly wind shear is pushing the convection west of the center which is partially exposed, and her central pressure is only 1009mb. This is really not an impressive system and is nothing but a rainy day for south Florida. I haven't seen any winds above 20-25 knots yet along the coast where this is coming ashore. Bonnie is not a big deal at all as expected. I expect this will remain the same story for the north gulf coast when Bonnie makes a 2nd landfall in about 36 hours, and she could even weaken some before then, possibly opening back up into a tropical wave before landfall.

A strong easterly flow aloft between the upper low to the west and the deep-layer ridge to the north is shearing Bonnie and not allowing any outflow channels to get established. This is not a good pattern for strengthening, and the forecast here remains the same, that Bonnie will likely weaken over the gulf and not be any stronger than she was over the Bahamas. The NHC intensity forecast for 45kts over the gulf even looks generous. I don't think Bonnie will even strengthen at all in the gulf.

Since the surface center has jumped a bit north this morning back under the mid-level center as the two flows become more aligned once more, the track may have to be adjusted a bit to the right. Bonnie is moving quite fast WNW at 18mph, and this quick forward movement is illustrating the strong and well-established steering flow around the southern periphery of the high over the SE US, and this will continue to steer Bonnie WNW until her 2nd landfall. Bonnie's center should pass over Naples as it heads out into the gulf later today, and I expect a fairly straight track towards the mouth of the Mississippi River, perhaps with a slight northward bend with time. Right now it looks like the stretch of coast from the mouth of the river east to Mobile Bay is the target area for landfall.

Overall, this is not a situation to be concerned about for residents along the north gulf coast. The only real concern here is for stronger SE winds coming over the oil spill and pushing the slick back in towards the coast. Otherwise, this is just a tropical rain event on tap for Saturday night.

Elsewhere....an area of disturbed weather behind Bonnie back near the Dominican Republic will be watched for mischief as it heads WNW across the Caribbean islands towards the Gulf of Mexico over the next several days. The upper-level environment is not the greatest in the world, and this doesn't appear to be a significant threat, but will be monitored.

Several strong tropical waves currently over the African continent will be monitored as they emerge out over the Atlantic and trek westward towards the Caribbean next week. We're getting really close to the time that one of these will pop out over the central-eastern Atlantic.

The only other area of potential concern next week will be off the southeast US coast and near Bermuda as an old front gets draped across the area in 4-5 days. Such fronts under the nose of an upper ridge can try to spawn warm-core type low pressure areas that can result in homegrown mischief, and this will have to be watched for trouble as it sits in the area for several days. Surface pressures will be rather high so the threat doesn't appear too significant right now, but I will be keeping an eye on it. Also interesting is the fact that some models take Bonnie's remnants right around the ridge eastward and back out over the SW Atlantic off the Carolinas in 4-6 days. This is right at the time that the front gets draped down in that area, so it will be interesting to see if we get some of Bonnie's remnants to mess around with the front and enhance the potential for homegrown mischief.

For now, tropical development is not expected through the weekend.

We shall see what happens!

Tropical Storm Bonnie Visible/IR2 Satellite (click image for loop):



Tropical Storm Bonnie Track Models:




Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






Updated: 4:52 PM GMT on July 23, 2010

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Tropical Storm Bonnie Evening Update Thursday July 22nd

By: Levi32, 1:44 AM GMT on July 23, 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. If HD quality isn't available, then it will be in a few minutes.



Tropical Storm Bonnie Visible/IR2 Satellite (click image for loop):



Tropical Storm Bonnie Track Models:




Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






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97L not a big threat; Atlantic remains mostly quiet

By: Levi32, 6:07 PM GMT on July 21, 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. If HD quality isn't available, then it will be in a few minutes.



The big story today is Invest 97L, currently located just north of Hispaniola. I'm not too impressed with this system, as it is located right under the SE quadrant of an upper low to its northwest which is shearing it and not allowing upper ridging to develop over the system, which is what you want for development. There is a very well-defined inverted surface trough just north of Hispaniola, but all the inflow is coming off of the Dominican Republic right now and as that air comes over those big tall mountains, it sinks and dries as it flows down the northern slopes right into 97L's circulation. As a result, convection isn't all that impressive right now with the system, and if it skirts close to Cuba that may continue to be a problem for it. Dry air getting punched in from the northwest by the upper low is also not helping.

The models, especially the GFDL and HWRF, look too far north with the track of this feature, and this should pass close to south Florida and continue WNW right on into the gulf, possibly trekking all the way across towards Texas. The ridge should remain strong and I don't really see this coming in east of Louisiana, but we'll see how it goes. The big problem for 97L is that the deep-layer ridge to the north is directing it WNW in tandem with the upper low, meaning that it can never get separated and put some distance between the two. The result is continuous shear and a generally unfavorable pattern over it for tropical development. I could see this possibly becoming a weak TD or TS, but more likely to not develop in my mind, and if it does, will not be a significant system. Regardless, south Florida may see some nasty conditions out of this as winds are howling out of the east on its northern side, and they may get the equivalent of a weak tropical storm coming through when this is all said and done.

Elsewhere....The wave behind 97L coming west of the windwards may have a chance to brew up some mischief as it comes westward over the next several days, as its alignment with the upper ridge will be more favorable for potential development down the road. This feature will also be getting into the Gulf of Mexico, and we'll have to keep an eye on it next week.

A tropical wave moving into the Bay of Campeche is developing a nice spin just west of the Yucatan, and this one is in a nice situation for development with the upper low over south Texas backing away westward, and upper ridging pumping over the western gulf. However, this feature will run out of time to develop and will be inland over northern Mexico in 48 hours, but this is a good illustration of what this system has that 97L is lacking. The alignment of the upper low and the ridge to the east of it relative to the surface feature is not right for development for 97L, but it is favorable for the tropical wave in the Bay of Campeche. If this were farther east, it would probably develop, but it will run out of time here. Still, heavy rains will once again move into northern Mexico and southern Texas with this, and several inches may get dumped on spots.

Overall, the Atlantic is still fairly quiet, and although there is a possibility we won't get that named storm before the month is out, that doesn't diminish how bad this season will eventually be. Once the lid comes off, all Hades will be let loose. That pattern of upper easterlies that I have been mentioning on the GFS for the past couple weeks over the tropical Atlantic is taking shape, and the TUTT is lifting northeast and out of the way. That's why we're seeing more cutoff upper lows retrograding westward with ridges in between them instead of a big TUTT across the entire SW Atlantic. Such a pattern is favorable for development if the tropical waves can get into the right position, under the ridges instead of the upper lows.

We shall see what happens!

Invest 97L Visible/IR2 Satellite (click image for loop):



Invest 97L Track Models:




Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






Updated: 6:09 PM GMT on July 21, 2010

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Invest 97L develops, not an immediate threat

By: Levi32, 3:37 PM GMT on July 19, 2010

The tropical wave mentioned on Friday in the central Atlantic is now passing just north of the Caribbean and is firing up all sorts of convection as it interacts with the TUTT low, as expected. This wave has been designated Invest 97L So far the trade wind flow has been too fast to allow any surface circulation to try to form, and the energy of the wave has been spread out a bit. With the upper low remaining close by to the northwest, convection will continue to go off, but 97L isn't an immediate threat to develop over the next couple days. Due to the nature of the trade wind flow, surface convergence will be more favorable for 97L once it gets farther west, in the vicinity of the Bahamas or Florida. The system will be in a more favorable position by Thursday or Friday, as the upper low may be more out of the way by then, causing less wind shear over 97L. Upper-level conditions don't look like they will ever be perfect for 97L this week, but if it happens to survive to get into the Gulf of Mexico, conditions may become more conducive then.

97L will be moving WNW over the next several days, just skirting the northern edge of the Caribbean islands. The main concern here is not for development but for the heavy rainfall that this system may bring to Haiti, although they are on the drier side of the wave, as most of the heaviest thunderstorm activity will remain to the north of them. Overall, 97L is not an immediate threat, but should be watched for signs of further development later this week as it moves through the Bahamas, and if it ends up in the Gulf of Mexico next week with sufficient moisture, it may be more a problem.

A pair of tropical waves moving through the western Caribbean also need to be watched. The leading wave is moving over the Yucatan Peninsula and the central Gulf of Mexico, and the 2nd one is now west of Jamaica. Both waves have decent wind shifts along their axis, but thunderstorm activity is currently limited. These waves will be heading WNW to NW over the next few days over the Yucatan and into the western Gulf of Mexico. The leading wave is moving in tandem with an upper low and doesn't look to be a big threat, but the wave behind it still in the Caribbean will have a more favorable upper-level environment, and will have to be monitored for possible mischief.

Elsewhere....there are no areas of immediate concern for tropical development. The central-eastern Atlantic will continue to be watched for our first Cape Verde development of the season, which may yet occur before July is out. Conditions are favorable for such a storm to develop, but so far dry air has been a limiting factor out there. The MJO is over our area of the world, and the Atlantic should remain convectively active through the end of the month, so we'll have to keep our eyes peeled.

We shall see what happens!

Invest 97L Visible/IR2 Satellite (click image for loop):



Invest 97L Track Models:




Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






Updated: 3:37 PM GMT on July 19, 2010

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The Atlantic is starting to get busy again

By: Levi32, 3:06 PM GMT on July 16, 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. If HD quality isn't available, then it will be in a few minutes.



After a fairly quiet period over the last week, the Atlantic looks ready to dish out some more activity from the tropics. A broad area of low pressure and building heat in the western Caribbean is generating a large area of scattered showers and thunderstorms, currently concentrated the most between 75W and 80W. This area is being ventilated by the TUTT to the northeast, and upper-level conditions are favorable for slow development of this area during the next several days as it moves WNW. Considering how broad this area is at the moment, I expect little from it for the next 2-3 days, but by the beginning of next week we may see something try to consolidate a little more to the east of the Yucatan. Steering currents are such that we will have to watch for something sneaking into the Bay of Campeche and trying to develop, yes again similar to Alex and TD 2 in terms of track. This is not a big threat right now, but is something to be watched for next week.

A well-defined tropical wave out in the central Atlantic along 41W is currently embedded in a dry, stable airmass and has no convection associated with it. This is partly due to the wave being so far north, with the majority of the wave axis found between 15N and 20N. This is quite far north for a wave to come off Africa. Although it lacks convection now, it has a nice low-level spin to it, and this will have to be watched for mischief as it comes farther west and interacts with the TUTT near the eastern Caribbean, which will likely result in some convective action along and east of the wave axis once it enters a more moist environment. This wave is not recurving, despite its high latitude, and is coming straight west or WNW north of the Caribbean and into the vicinity of the Bahamas in 5-8 days.

Overall, things are still quiet, but look to be picking up a bit again, and the MJO is coming into our area of the world now, which will result in a focusing of upward motion back over the Atlantic and Africa during the next couple weeks. The 2 storms I forecasted before July 15th did not materialize, as we only got Alex. TD 2 nearly gave me the 2nd one. However, there is still a lot of room for a historically active season, and people should not let their guard down on this year. Keep 2004 in mind, which didn't even see the "A" storm until July 31st. This season has the potential to run away with itself once it finally gets going, and I still think we have a pretty good chance of another named storm before the end of the month.

We shall see what happens!


Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






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Tropics are quiet for now

By: Levi32, 4:58 PM GMT on July 13, 2010

The tropics remain quiet in the Atlantic, and should remain that way for the rest of this week. A massive cloud of dry air and dust from the Sahara moved off of Africa several days ago, followed by a second burst, and in combination with each other they have managed to cover most of the tropical Atlantic between the Caribbean and Africa. This has been contributing to the quiet spell we are currently seeing. The cloud is now beginning to dissipate, and the ITCZ and African wave train will gradually start to heat up again over the next couple weeks.

There are some very potent waves coming off of Africa right now, and although they are getting knocked down by the SAL, such waves should continue coming off, and eventually they are going to start finding the right pattern to develop. The GFS is consistently showing a favorable pattern of upper easterlies developing across the entire tropical Atlantic up to 20N, which is a very friendly setup to tropical waves. I still would not be surprised to see one of them develop in the central-eastern Atlantic before the end of this month, as the MJO is moving into our area of the world now, and the center of upward motion will be in a favorable spot for Cape Verde development. The western Caribbean will be the other place to watch for mischief over the next couple weeks, as although lots of these tropical waves are getting knocked down as they come across, some of them may still try to cause trouble once they get all the way west into the Caribbean, especially as the MJO comes back across.

Elsewhere....the world is very quiet in terms of tropical activity. The west Pacific finally got another tropical storm, but it is forecast to remain under typhoon strength, and they are off to a record slow start so far this year. This is a testament to how the global pattern is favoring downward motion in the Pacific and upward motion in the Atlantic and Indian oceans.

The east Pacific is likely to see something attempt to spin up somewhere over the next several days, as the MJO is currently in a favorable position to support upward motion in that area, and indeed there is currently a lot of convection going off across the basin.

Overall....the rest of this week should remain quiet in the Atlantic, but things should start heating up again before the month is out.

We shall see what happens!


Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






Updated: 5:00 PM GMT on July 13, 2010

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Tropical Tidbit for Friday, July 9th

By: Levi32, 4:24 PM GMT on July 09, 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. If HD quality isn't available, then it will be in a few minutes.



The tropics are fairly quiet today, at least compared to the last couple of weeks. There are three tropical waves tracking westward through the Caribbean which all have decent convection associated with them right now, which makes their bark look worse than their bite. This convection is being enhanced by upper divergence associated with the TUTT to the north, and it is common for tropical waves to blow up with thunderstorms when they near the TUTT, but the TUTT also shears them, making them have to wait until they get farther west to develop where they can encounter more favorable conditions. The western Caribbean will be the place to watch as these waves pile into the area over the next 10 days, but some decent ridging building into the Gulf of Mexico will be shoving most of these westward or WNW into central America, and thus they may not have the necessary time to significantly develop. Regardless, the area will be monitored.

The cut-off trough-split low off the eastern seaboard is actually centered right over Cape Hatteras this morning, and energy hasn't been able to bundle very well near the center, so it looks like this system won't be able to warm its core enough to make a full subtropical transition. It got close, but it is out of time now as it will be getting dragged northward by a front coming into the northeast US. The main impact of this low will be to enhance heavy rainfall over the northeast this weekend as it throws tropical energy into this front as it gets absorbed into it.

The eastern Atlantic will continue to be monitored for Cape Verde Mischief as a couple of potent tropical waves are set to come off Africa next week. The first one coming off right now is sacrificing itself to the large area of dust and dry air from the Sahara which came off into the eastern Atlantic a couple days ago, and this will kill this particular wave on its way westward. This will help clear the way for the next two waves behind it though as it moistens up the environment ahead of them, and these next two will have to be watched. The ECMWF and the GFS were developing these but have since backed off a bit in recent runs. Regardless, the GFS continues to show a favorable upper-level pattern developing over the eastern Atlantic with upper easterlies becoming dominant during the 10-15 day period, and these are very friendly to tropical waves trying to develop out there. We are getting deeper into the season now and it would not be surprising to see our first Cape Verde storm develop during the 2nd half of July.

Overall, it will likely be fairly quiet in the tropics for the next week or so, and we should enjoy it while we have it, because it won't last too long. The last 10 days of July may see activity pick back up again, and once it really gets going, it may not stop for quite a while.

We shall see what happens!


West Atlantic Visible/IR2 Satellite (click image for loop):



Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






Permalink

TD 2 a big flooding threat; Possible Cape Verde trouble during 2nd half of July

By: Levi32, 5:34 PM GMT on July 08, 2010

No video today.....slept in past 9:00 again. My alarm didn't even wake me like it usually does. You know, when you stay up late for a week of nights tracking the first big hurricane of the season, and then sacrifice the rest of the night getting your Calculus homework done, you find out that it's not a very lucrative schedule lol. My body absolutely demands 8-10 hours of sleep and I've been giving it much less, even after Alex left the scene. Obviously I need time-management counseling before I attempt juggling 4 classes this fall with the peak of the hurricane season lol.

Tropical Depression #2 was classified last night in the western Gulf of Mexico. The system lacked convection all the way across the gulf, and the reason for that, which I have been saying, is Alex's cool SST wake that he left across the western gulf, and TD 2 moved right over that wake. SSTs may be 27-28C, seemingly very much warm enough to support tropical development, but for some systems this is not enough in the short term. When you spawn a larger system like TD 2 in the Caribbean from pure heat bundling with no preexisting disturbance, it starts out with a diet of 30C SSTs and massive atmospheric heat content. When you suddenly cut that down to 27-28C, it has side-effects on the system because it's used to gobbling up more heat. A smaller system or a true tropical wave wouldn't have had as much trouble because it wouldn't be such a hog, but 96L was one of those decoupled systems that has to use a lot of energy to even stay alive.

The surface center shot up into the gulf and had no problems generating thunderstorms, but the mid-level center back down over the Caribbean had to work hard and use all the energy available just to keep any convection going to sustain the mid-level circulation. When it moved over the Yucatan and out the other side, the energy supply wasn't enough to sustain it without its surface partner, and it fizzled. At this point the surface center started redeveloping at the area of lowest pressures in the western gulf, but now it had lost its support in the mid-levels, and apparently there was not enough heat energy to allow the surface center to feedback. Eventually such systems can "adjust" to their environment, but TD 2 needed time to do that, and time was one thing it didn't have, unlike Alex, which had to go through a similar process.

TD 2 is now coming ashore just south of Brownsville and all sorts of convection is going off with it now as it makes landfall. Why? Because it is now out of Alex's cool wake. Alex went into Mexico farther south and this is where their paths diverged, right before landfall, which is when TD 2 was finally able to make its move. The system is also probably starting to adjust to its new environment as well. Fortunately, this entire process happened too late for TD 2 to be a major storm, but it is a major threat to the areas of Mexico that were soaked by Alex, as it is going to dump a lot of heavy rain on some of those same areas. Hopefully everyone has been properly warned about how dangerous this system really is. Southeast Texas will also be dealing with potential flooding issues with yet more heavy tropical rains today.

Elsewhere....The trough-split off North Carolina has worked down to the surface and is entraining tropical moisture from an old tropical wave. Convection has been going off sporadically but so far the energy isn't bundling much near the center, and right now chances for subtropical development look low. This system will be sitting there for the rest of the day but tomorrow will be lifted north by an approaching longwave trough. This will not be much of a weather-maker for North Carolina except for some scattered showers rotating around it, but it will be getting entrained into another system moving across New England in a couple days, and this added tropical moisture could mean heavy rains for them this weekend.

A couple small ITCZ disturbances moving into the Caribbean over the next several days will be monitored for any mischief, but chances look low at this time.

A tropical wave over eastern Africa will be watched as it tracks across and emerges over the Atlantic in 6-8 days. The ECMWF and GFS have been hinting at possible Cape Verde development after the 15th, and the pattern will indeed be favorable for such a storm to develop. We're getting to that time of year to start keeping a lookout to the east.

We shall see what happens!

Tropical Depression 2 Radar (Brownsville):



Tropical Depression 2 Visible/IR2 Satellite (click image for loop):



Tropical Depression 2 track models:




West Atlantic Visible/IR2 Satellite (click image for loop):



Caribbean/East Pacific Visible/IR2 Satellite (click image for loop):



Central Atlantic Visible/IR2 Satellite (click image for loop):



Atlantic Tropical Surface Analysis:



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






Updated: 6:30 PM GMT on July 08, 2010

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96L developing, but too late to be a huge problem

By: Levi32, 5:44 PM GMT on July 07, 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.



Invest 96L is now starting to organize, and if this system had 3-4 more days over water it would be a big big problem for the west gulf coast, but as it stands this has 24 hours before landfall near the TX/MX border and will not have the time to bring anything more than nasty tropical weather to coastal northern Mexico and southeast Texas, with heavy rains and up to gale-force wind gusts at the coast to the north of where this makes landfall.

96L's mid-level center which became well-defined over the Yucatan last night is now moving off into the gulf, but it doesn't have to do all the work on its own like we thought it would have to yesterday. The surface trough that was up in the central gulf yesterday has continued northwest and is starting to bring thunderstorms and windy weather into SW Louisiana and NE Texas, but the southern portion of the trough is hanging back near the area of lowest pressures, and the surface circulation is starting to become much better defined nearing 24N, 93.5W. This is amazing to see because it is exactly what happened with Hurricane Alex 2 weeks ago when he was out in the Caribbean. His surface center ran off towards the area of lowest pressures and made the mid-level center play catch-up, but they did eventually get married, vertically stacked, and off the storm went and bombed out before hitting Belize.

This is what 96L is doing now. The surface center initially ran off, but the southern portion of that surface trough has hung back and is now becoming well-defined at the area of lowest pressures relative to normal. Now that it's in that area, which has been sitting there for a few days now, it will start to wind up, and you will see this thing really try to develop now that it is bringing the mid-level center in. Once the surface and mid-level centers get stacked later today, this thing will really try to ramp up. It's over the cold SST wake of Alex so that may be a limiting factor, but if this starts to feedback it just might make a run at TD status, and you never know it could even try to become Bonnie, but it has some obstacles to clear in order to get there. This is the point where things really start to come together for 96L if it can overcome the dry air to its west, which may be another limiting factor.

Overall, if this had more time, it would be a huge problem, but it does not have the time to be more than a pain in the neck for northern Mexico and south Texas. The entire coastline from northern Mexico up to Louisiana should be expecting very tropical weather with heavy rains and gusty winds, possibly to gale-force in some areas of south Texas, as this system comes ashore.

Elsewhere....the trough-split occurring off the Carolinas is entraining an old front and a tropical wave which is bringing a lot of tropical energy into the SW Atlantic. It will be interesting to see if the upper low can pull this energy underneath and try to feedback some kind of hybrid low as it lifts out to the north in a couple days. This is not likely to be a significant tropical development, but may bring some nasty weather to coastal New England and the Maritime provinces of Canada on its way northward, if it comes far enough west. Overall this is not a significant concern.

A couple of tropical waves with associated ITCZ disturbances in the central Atlantic are not in a hurry to develop right now, but will be entering more favorable environmental conditions in the Caribbean down the road in the next 5-8 days, and will be watched for mischief.

During the last few days the long-range GFS has been depicting a very favorable pattern for Cape Verde development, and really development in general across the entire tropical Atlantic during the 2nd half of July, and I show you this pattern on the video. The ECMWF and GFS have been hinting at mischief in the eastern Atlantic in 10-15 days, so I will be keeping an eye on this pattern to see if it verifies. We're getting into the meat of July now, and it would not be surprising at all to see our first Cape Verde-type development out in the central-eastern Atlantic at some point this month. Things are about to start humming out there.

We shall see what happens!

Invest 96L Visible Satellite (click image for loop):



Invest 96L 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):






Updated: 6:05 PM GMT on July 07, 2010

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Watching 96L and a Trough-split off the SE US coast

By: Levi32, 6:11 PM GMT on July 06, 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.



The tropics remain fairly active today. Invest 95L moved onshore in Louisiana last night as a well-defined, tight little spin with some gusty winds around it, but lacked any significant convection and was not really a classifiable system. The NHC got nervous and went from 0% chance for development to 60% chance in a special tropical weather outlook a few hours before 95L made landfall. My question is why they were even thinking about naming this when they have completely dismissed countless other systems over the years that have looked 100 times better than 95L ever did near our shores? Oh well.

A trough-split getting set to occur off of the southeast coast is going to be capturing an old frontal boundary draped north and east of the Bahamas which is entraining the northern portion of a tropical wave that entered the eastern Caribbean yesterday. This energy, if it can get bundled under the trough-split, could cause some mischief off the SE US coast over the next few days. Surface pressures are a bit on the high side so it will be hard to get something going, but we saw what happened with 95L along the old front, so this area will have to be watched closely as home-grown mischief is exactly that, home-grown close to our coastline. The trough-split will also be all the way up to 200mb, meaning that there is a lot of cold air aloft which could make development start out not purely tropical, and the upper pattern will be complicated. We'll see how it works out. The system would likely stay off the eastern seaboard and ride north towards New England or the Canadian Maritimes.

A couple of ITCZ disturbances out in the central Atlantic are being monitored for possible mischief once they get into the Caribbean under a favorable pattern aloft, but right now they are not in a hurry to develop way out there.

The biggest story right now is Invest 96L. This system is another product of the overall pattern where building heat and lowering pressures are getting focused in the western Caribbean and Gulf of Mexico, and the resulting disturbance is not unlike monsoonal depression development in the Indian Ocean or Western Pacific. It's the same thing we talked about with Hurricane Alex.

The surface center with the burst of strong gales on its eastern side has taken off to the north and is now in the central Gulf of Mexico heading up towards southwest Louisiana. The mid-upper center is staying behind near the eastern Yucatan where the greatest concentration of heat is, and this is not unusual to see a decoupled system in this kind of pattern. Typhoons do it all the time, but they always have a big wide open ocean with days upon days to get it together and develop. Alex had the time and became a major hurricane, but 96L does not have enough time to pull itself together. It is obvious that the surface center does not want to get married to the mid-upper feature, and their divorce kills a lot of the hope for this system to develop.

96L still has a chance though, because with the low-level flow taking the surface feature rapidly northwestward, the mid-level center is left behind farther south and is more sluggish with its movement. It is possible this could work its way down to the surface and form a new surface low out in the southwestern Gulf of Mexico over the next couple days once the old low is out of the way and has moved into western Louisiana. An upper low currently over the western gulf is shearing the current surface low in the central gulf, but this upper low will be backing away over the next couple days and ventilating the western gulf as 96L's mid-level piece comes across, and the environment should be at least marginally favorable for development should the mid-level center try to work down to the surface. If it does, the track will be farther south towards northern Mexico or south Texas. Right now I give it a low chance of development. Regardless, the surface feature moving inland near SW LA or NE Texas in 36 hours will be bringing heavy tropical rains and tropical storm-force winds to portions of the coast, and people should be aware that active tropical weather is headed their way this week regardless of development.

We shall see what happens!

Invest 96L Visible Satellite (click image for loop):



Invest 96L 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: 11:54 PM GMT on July 06, 2010

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Several areas of concern to watch this coming week

By: Levi32, 4:44 PM GMT on July 03, 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.



There are several different areas to watch for mischief this coming week. The first area of immediate concern is Invest 95L, a surface low along an old frontal boundary in the northern Gulf of Mexico associated with an upper trough-split. This low is gradually deepening as pressures lower in the area, but thunderstorm activity is limited as the system is getting sheared a bit from the north. The system is vertically tilted to the ESE with the 500mb low to the east of the surface low, and there is more of a 200mb (very upper) low than I thought there would be, and that always makes development a bit more difficult and a slower process. 95L will be drifting WSW and eventually curving northwest, inland somewhere in Louisiana in 2-3 days. While this feature should be watched closely due to the oil spill and the fact that home-grown mischief should always be followed loyally, I believe development chances with this disturbance are low, as it should just simply run out of time.

A 2nd trough-split will be occurring with the trough off the easter seaboard in a couple days, and a new surface trough or low will be forming near or east of the Bahamas underneath the trough-split. The ECMWF and GFS seem to want to decouple these two features and take the upper trough-split westward into the eastern Gulf of Mexico while leaving the surface low behind off the SE US coast. Now if the features remain vertically stacked then this could cause a problem in the Gulf of Mexico, but if they decouple then the surface low would get caught in the low-level steering flow and get taken north towards the Carolinas and likely get strung out. Surface pressures off the SE US will also remain rather high next week. In such a situation chances for development would be low. This area will have to be monitored though. Home-grown mischief can be very sneaky.

A tropical wave entering an area of low pressures and building heat in the western Caribbean is setting off a broad area of showers and thunderstorms that will be propagating slowly WNW towards the Yucatan and Bay of Campeche over the next few days. This pattern is not unlike what spawned Hurricane Alex, and this feature has a decent chance to try to develop in the Bay of Campeche. The ECMWF and CMC support this, but the CMC takes it as a hurricane into Texas, which is likely too far north. The pattern hasn't changed much since Alex went ashore, and the big ridge over the eastern US should direct this feature as far or farther south than Alex went. Hopefully Mexico doesn't get a double-hit, but if this develops, they likely will. Such a storm would likely be much weaker than Alex was, due to all the upwelled cold water in the SW gulf left in the wake of Alex's passage.

Finally, a tropical wave east of the Caribbean along 54W has lots of thunderstorm activity and a well-defined inverted-V signature on satellite imagery. This feature, in my mind, may pose the greatest threat of these 4 concern areas, although this would be the farthest down the road of them all. This tropical wave is not developed by any of the models at this time, but it will be moving into an area of building heat in the NW Caribbean and Gulf of Mexico in 7-8 days, and I believe the pattern by this time will be ripe and favorable for another storm in the gulf, should this wave decide to take advantage.

The big ridge over the eastern US is shifting north from its average position during June, and this shifts the subsidence (sinking air) north and opens up the Gulf of Mexico for upward motion and building heat. Upper ridging (200mb level) results, and with the ridge farther north it means troughs out over the western Atlantic try to dig down, then get kicked out and their tail-pieces split off behind them east of Florida. These pieces can either retrograde west into the gulf and try to develop, or they can stay east and help ventilate the gulf and western Caribbean along with the TUTT. Such a pattern is very favorable for mischief in the Gulf of Mexico, and this tropical wave east of the windwards may be moving into an area that will be conducive for it to try to develop by the end of next week.

Overall, the tropics are active right now, and although I am more concerned about the disturbances in the deep tropics than I am about the trough-splits right now, they need to be watched too as trough-splits over old frontal boundaries always look to cause trouble, and should be monitored closely as they are very close to our shores.

We shall see what happens!

Gulf of Mexico Visible Satellite (click image for loop):



Invest 95L 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: 4:45 PM GMT on July 03, 2010

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Double-trouble for the Gulf of Mexico? Western Caribbean to be watched

By: Levi32, 5:17 PM GMT on July 02, 2010

No video today. I can only afford a quick post.

As I have talked about for the last 3 days, there is concern for trouble in the NE Gulf of Mexico over this weekend and into next week. A surface low which I analyzed yesterday has finally been put on the surface map this morning at 1015mb over Apalachee Bay, along an old frontal boundary which has found its way down over the northern gulf, and has lost most of its frontal characteristics. Light but widespread convection is associated with this front, but is all located to the south of the low center. This is not due to dry air, but northerly wind shear from the remnants of Alex's outflow. This shear will be relaxing gradually over the course of the next couple days as the surface low drifts WSW, and as surface pressures lower across the gulf, we could see this low become a warm-core feature that would have a chance at development. This system has already been designated Invest 95L.

95L formed in association with an upper trough-split, and thus has upper energy with it. This piece of energy will be backing WSW or SW over the gulf for the next couple days, and will eventually curve back towards the west or northwest. This isn't going east like the CMC showed last night, as the trough to the east is lifting out and the ridge to the north will be the primary steering feature. All in all, a trough-split over a stalled-out front in the Gulf of Mexico always means trouble, always. Home-grown mischief is very possible in this situation, but the system will need another day or so over water to give shear a chance to relax, before it can try to develop.

We are actually going to end up with 2 trough-splits from this pattern. 95L is number 1. Number 2 comes east of Florida early next week when the trough lifting out splits again but this time a bigger piece comes off. This piece will also slowly retrograde west and could also end up in the Gulf of Mexico right behind 95L. Since the trough-split will be occurring all the way up to the 200mb level, it would be a more difficult but interesting event to see it work down to the surface and form a low. In this type of trough-split event, initial development would have the chance to start out subtropical instead of tropical.

Elsewhere....heat is building in the western Caribbean as the trade wind flow gains a more southerly component to it again, causing convergence and piling up of air in that area. Heavy convection is being supported by cold air aloft associated with a TUTT cell moving southwest. As this upper low backs away over the next few days, it will ventilate the area as upper ridging builds in its place, and a tropical wave moving into the SW Caribbean combined with the generally convergent flow through the area will continue to support convective activity, in almost a similar fashion to before Alex formed. The ECMWF continues to hint at something crossing the Yucatan and developing in the Bay of Campeche. This scenario is entirely possible with this pattern, and the western Caribbean and BOC area will have to be watched next week for mischief.

The tropics are heating up, and we'll see how I do with the prediction of 2-3 named storms by July 15th.

I should be able to do a video tomorrow.

We shall see what happens!

Gulf of Mexico Visible Satellite (click image for loop):



Invest 95L 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: 5:18 PM GMT on July 02, 2010

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Tropical Tidbit for Thursday, July 1st

By: Levi32, 4:43 PM GMT on July 01, 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 made landfall last night as a Category 2 hurricane, and is currently drenching the people of Mexico with heavy rains, causing flooding which has already claimed lives. Our hearts and prayers go out to them. Alex was an incredible storm to see at this time of year. A couple hours before landfall the recon left Alex after recording a pressure of 947mb, which occurred during a period of rapid strengthening. It is likely that Alex went lower than this before landfall, and likely beat Hurricane Audrey (946mb) for the lowest pressure ever in an Atlantic storm during the month of June. Alex will go down officially as the 2nd strongest storm ever recorded in the month of June in the Atlantic. My forecast for Alex to make landfall in Mexico near 25N ended up too far north, but the intensity forecast verified nicely with this storm.

Looking ahead now in search of Bonnie, there are a couple of well-defined tropical waves out in the Atlantic, one approaching the windward islands and another out at 40W. The NOGAPS jumps on both of these, especially the one at the Windwards, and develops it into a tropical cyclone in the western Caribbean in 6 days. The ECMWF shows slow amplification of the wave in the Caribbean and then tries to develop it in the Bay of Campeche, a similar track to Alex. With the upper pattern becoming favorable in the Caribbean again now that Alex is moving away, it is entirely possible that we could see some mischief from this wave down there, although it will likely have to get to the western Caribbean before being able to cause any trouble. The CMC model isn't so impressed with this wave, but jumps on the one behind it at 40W and develops it north of the Caribbean in 6 days. The UKMET shows the wave as a very amplified feature in 5 days over the Antilles Islands. Both of these waves will be monitored closely.

There may also be trouble closer to home here in the US, as a trough-split is set to occur in the vicinity of Florida early next week. The trough currently over the east will be lifting out over the next few days, and the ridge building behind it will cause the tail-piece to split off and meander westward into the Bahamas and Gulf of Mexico. The GFS forms multiple areas of weak low pressure along the old frontal boundary that will be draped across the region, and when you get blocking over the top to the north, a trapped front with a trough-split in the mid-levels over the Gulf of Mexico is never a good thing. In the video I show this, and illustrate why this may be a recurring problem this month with the pattern that is shaping up. This area will have to be watched for mischief on either side of Florida in 4-7 days, although development, if any, is likely to occur west of Florida in the Gulf of Mexico, rather than east.

The MJO is once again getting stuck near our area of the world in octans 1 and 2, as the warm water in the Atlantic is trying to hog the upward motion in the worldwide tropics. We will see a lot of this sort of thing this season where the MJO keeps trying to return to octans 8, 1, and 2, and has a hard time leaving to go around the circle. As a result, no significant or prolonged downward bursts are expected, and the MJO getting stuck in our area of the world means that the tropics are likely to stay active. I opined back in early June that the period as we neared the end of June to mid-July would mark the real kick-off to the season, and that we could see 2 or 3 named storms by mid-July. We've already got one, and we'll see how the next 2 weeks go.

We shall see what happens!


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: 4:55 PM GMT on July 01, 2010

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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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