Tropical Tidbits from the Tundra

Ophelia becomes a Cat 3; Double major typhoon hit for Luzon within a 5 day period

By: Levi32, 4:24 PM GMT on September 30, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Hurricane Ophelia, despite wind shear and dry air impeding on her, has strengthened into a Category 3 hurricane, the 3rd major of the 2011 hurricane season. This was a bit unexpected due to the seemingly only marginal conditions around her. This is another lesson in how the cores of hurricanes are still fairly unpredictable. A semi-clear eye has popped out, and the storm's structure looks as healthy as ever. Ophelia shouldn't be able to strengthen much more and should weaken slightly as she moves into increasingly higher shear to the north. The good news is that she should pass off to the east of Bermuda without a direct hit, though she could still spread tropical storm conditions over the island.

Tropical Storm Philippe looks like nothing important and is moving northwest out over the central Atlantic. He is being caught underneath the ridge to the east of Ophelia and will be forced to move WSW eventually in a couple of days. This will bring Philippe uncomfortably far south, but he should still recurve sharply out to sea due to several troughs transitioning through the eastern seaboard during the next 10 days. Bermuda again may have to keep an eye on this storm due to his westerly track. The United States should see no threat from Philippe.

Out in the western Pacific, Luzon, the most populated island of the Philippines, is bracing for its 2nd direct hit from a major typhoon less than 5 days after Nesat roared ashore. Typhoon Nalgae is a Cat 3 that will make landfall near the exact same location and take nearly the same track westward. The good news is that the cold water wake left by Nesat should keep Nalgae from strengthening into a supertyphoon, but this is still a very bad situation for Luzon. Nalgae will go on to hit China in a similar place to Nesat, but a massive pool of cold water left by Nesat's several days of churning should make it very difficult for Nalgae to regain anything above Cat 1 strength in the South China Sea.

Looking ahead in the Atlantic...the models are starting to look more and more mischievous in the Caribbean and Bahamas areas starting by 8 days from now, due to high pressure building over New England and the eastern United States. Such high pressure tends to incubate the Caribbean, especially in October. The MJO is finally on the move, and since the move is now tangible instead of forecasted, I think it will finally start its journey across the Pacific, eventually ending up in the Atlantic, which will enhance upward motion and turn the Caribbean into a much wetter place. The eastern Pacific might try to get a storm out of this pattern as well before it is the Atlantic's turn. With the MJO finally coming, and in tandem with high pressure to the north of the Caribbean, we will have to look for tropical mischief during the 2nd week of October.

We shall see what happens!

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



Atlantic Tropical Surface Analysis:



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






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Bermuda should watch Ophelia; Tropics overall pretty quiet - that should change soon

By: Levi32, 4:32 PM GMT on September 28, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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We shall see what happens!

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



Atlantic Tropical Surface Analysis:



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






Updated: 4:35 PM GMT on September 28, 2011

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Ophelia dead but may come back to life; Reasons to still watch the Caribbean

By: Levi32, 4:57 PM GMT on September 26, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Ophelia was finally downgraded yesterday, after probably being unworthy of a name for over a day before that. Her old center scooted off to the west and is now northwest of Puerto Rico. A new surface center is trying to develop just west of the convective mess, which is home to her mid-level center. She will probably try to redevelop into a tropical cyclone at some point over the next few days as the upper low to her northwest that has been shearing her backs away, relaxing the shear a little bit. She will be recurving east of the United States, but possibly close enough to Bermuda to impact them, and thus they should keep an eye on her. She shouldn't be that strong of a storm either way.

Philippe is also curving out to sea into a large trough in the eastern Atlantic.

At the risk of sounding like a broken record, the Caribbean still needs to be watched during the next couple of weeks. One has to be humbled once in a while by the unpredictability of the timing of things like the MJO, which is what we are waiting on. The GFS and UKMET were way too fast in bringing the MJO to phase 8 at the beginning of this month, and the ECMWF had the better idea of being slower, though it was wrong about plunging the MJO deep into octants 4 and 5. Overall it is a hybrid of the ECMWF's slowness and my idea that the MJO will eventually come back to the Atlantic for October. Once it finally does, then I think we will see the Caribbean turn very wet.

I show in the video today how the CPC analogs for Day 11 are full of storms from the package that I outlined over a week ago in relation to this overall pattern. This kind of setup has spawned storms before, and it could do it again.

We shall see what happens!

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



Atlantic Tropical Surface Analysis:



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






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Ophelia weak but could bring rain to the islands; Lessons from the western Pacific

By: Levi32, 4:29 PM GMT on September 23, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Official NHC Forecast for Tropical Storm Ophelia:



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



Atlantic Tropical Surface Analysis:



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






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Ophelia forms; Still concerned about the western Caribbean for early October

By: Levi32, 4:43 PM GMT on September 21, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Tropical Storm Ophelia has developed in the central Atlantic. Although she now has a well-defined surface circulation, she is already sheared, with an exposed center west of the main cluster of thunderstorms. This will likely be how Ophelia looks for most of her life. She will likely pass over the northern-most Leeward Antilles islands and then north of the greater Antilles, eventually recurving or being absorbed into a frontal boundary off of the eastern United States, no threat to the eastern seaboard. While not likely to be a significant wind event, the back side of Ophelia could bring heavy rains to Puerto Rico again, which would be devastating. Even if Ophelia passes well north of PR, trailing spiral bands coming around the back side could bring rain to the islands even as the storm center is a few hundred miles to the northwest.

Looking ahead...I feel like I'm beating a dead horse, but there is still concern for tropical mischief in the western Caribbean in the 10-15 day period as the MJO finally comes back to the Atlantic. This factor is what we're probably waiting on now, as the Caribbean has not shown any signs of wanting to light up without the upward air motion that the MJO provides. Even the ECMWF is now coming around to the idea that the MJO will come back to the Caribbean within 15 days, after stubbornly suggesting otherwise, but we knew that eventually it would have to come around. Renewed upward motion, combined with high pressure over the eastern U.S., is a recipe for late-season fun and games in the western Caribbean that could result in a storm that tries to find its way northeast towards the eastern gulf or Bahamas.

We shall see what happens!

Official NHC Forecast for Tropical Storm Ophelia:



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



Atlantic Tropical Surface Analysis:



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






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98L slowly organizing; Pattern favors threat from the NW Caribbean in early October

By: Levi32, 4:52 PM GMT on September 20, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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We're still watching invest 98L in the central Atlantic. The system became larger overnight as it absorbed a secondary mid-level center, and the broad circulation needs to tighten up a bit now before it can close off fully and be declared a tropical depression. It doesn't have that much to do to get there though, and we will likely see a tropical depression or storm within the next couple of days. The environment supports some strengthening until about 55W, where wind shear increases. Direct evidence of this is old 99L's circulation being obviously sheared by upper-level westerlies. This shear will likely remain around the northeast Caribbean for the next week, making it difficult for 98L to strengthen much beyond a moderate tropical storm, similar to Maria. A hurricane seems unlikely, though folks in the Antilles should keep a close eye on 98L.

The track of 98L is fairly straight forward. A WNW track towards the leeward Antilles to the south of the subtropical ridge should be the rule for the next few days, with a more NW turn occurring west of 65W, probably taking 98L into the areas of Puerto Rico, Hispaniola, and the Bahamas. This would be bad news for Puerto Rico, as they don't need anymore rain. Even in the Bahamas 98L may not find a favorable environment for strengthening, and may get absorbed northward into an elongated frontal boundary. In other words, 98L may be another dud storm in terms of intensity.

Looking ahead...there is still concern about the upcoming pattern for early October in the western Caribbean. Originally this concern was for late September, but the pattern is taking a little bit longer to evolve. However, everything points to it eventually evolving to a point where as the MJO comes back into the Caribbean in 10-15 days, high pressure over eastern North America will stimulate surface convergence in the western Caribbean and allow a storm to try to form, which could move north or northeast into the eastern gulf, Florida, or Cuba/Bahamas area. Such a storm would be a guaranteed land threat and this pattern should be monitored closely, though we are likely still 10 days or more away from potential development.

We shall see what happens!

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



Atlantic Tropical Surface Analysis:



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






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98L to affect the leewards but not horribly strong; Watching Caribbean in long range

By: Levi32, 4:40 PM GMT on September 19, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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We have a new invest in the central Atlantic, designated 98L. This is an area of monsoonal low pressure which is exhibiting excellent mid-level rotation in a consolidated area of thunderstorm activity. The surface circulation is not quite closed yet, and is lacking pure northerly winds on the western side and pure southerly winds on the eastern side. This is a typical monsoonal convergence pattern. It appears likely that the circulation will eventually close off and make 98L a tropical depression, and I wouldn't be surprised to see it declared one within the next day or two. Environmental conditions look favorable for development during the next couple of days, but as 98L approaches the leeward Antilles, wind shear will probably increase in the face of an upper trough north of the Caribbean which is forecasted to stay in place for at least the next week. This may keep 98L in check similar to how Maria struggled, and at this point it would seem hard for 98L to attain hurricane status. However, wind shear forecasts 5-7 days out are a bit uncertain, and the islands should closely monitor 98L's progress.

As alluded to above, steering currents should carry 98L in the general direction of the leeward Antilles islands. Puerto Rico and Hispaniola may get some more rain from this system, and that's the last thing that Puerto Rico needs after all of the rain they have had so far this season. Even without a big wind event, the rain alone could be devastating. 98L would likely continue northwest into the Bahamas area ahead of an upper trough over the eastern United States, which will likely recurve it eventually. At this point I still wouldn't expect 98L to be getting very strong, and some global models even dissipate it. As far as any threat to the U.S. goes, I wouldn't worry too much about it right now until we see what it looks like in the northeastern Caribbean.

Looking ahead....we're still watching the western Caribbean, southern gulf, and Bahamas area in the long-range. My original target time period of September 15th-25th is proving to be too early, and the development window may be shifting right into the first week of October now, so my timing was a bit off. However, the logic of why development is likely to occur eventually in this pattern still stands, and although we will have to climatologically turn our eyes towards the Caribbean during October anyway, I think that this pattern means there is an above-normal chance of development occurring. The MJO coming back is probably the last ingredient that we need, and it is forecasted to come back to the Caribbean within 15 days. The ensemble means still show a very wet Caribbean with very low pressures in 12-15 days, illustrating the need to be on the watch.

We shall see what happens!

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



Atlantic Tropical Surface Analysis:



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






Updated: 4:41 PM GMT on September 19, 2011

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Maria skirting Newfoundland; Atlantic very quiet for the moment

By: Levi32, 4:34 PM GMT on September 16, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Hurricane Maria is about to brush Newfoundland with a few hours of very nasty weather. I have not seen any wind reports within the last 2 hours of anything over 40kts there, so hopefully conditions will not become too dangerous, but hurricane-force gusts are likely right along the coast where the center passes. Maria is racing northeastward at 52mph and will be out of there quickly, probably not too big of a deal for residents there, but still a fairly dangerous storm.

The rest of the Atlantic is dead quiet by mid-September standards. The culprit for this is likely a downward pulse in the MJO which is bringing sinking air over much of the Atlantic right now, which suppresses thunderstorm activity. This is forecasted to reverse to an upward motion pulse within the next two weeks by the GFS and UKMET. The ECMWF stubbornly keeps the MJO in octants that favor downward motion over the Atlantic for the next 15 days, but with the Atlantic still being the warmest ocean basin in the tropics right now, upward motion will likely return to our area of the world for this latter part of the hurricane season.

As the MJO returns, troughiness is expected to set up over New England, and this kind of a pattern has been known to spark development in the western Caribbean in the late season. While none of the models currently show significant development, they continue to show a very wet Caribbean from late next week through the following week, and broad low pressures overall in the area. I have been speaking of the potential for development in this area too long to drop it now until we get through this period where I think it is likely to be attempted. This area should be watched through at least the end of the month, and possibly even into October, because as the Cape Verde season shuts down, the Caribbean will become our biggest focus until the season comes to an end. We just now passed the peak of the season, and the current lull is good but misleading. We still have a long way to go before it's all said and done.

We shall see what happens!

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



Atlantic Tropical Surface Analysis:



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






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Maria to stay fairly weak; Still looking at potential mischief in the Caribbean

By: Levi32, 4:39 PM GMT on September 14, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Tropical Storm Maria remains sheared from the southwest and is apparently unable to take advantage of the slightly better ventilation that she is receiving from the upper trough that is recurving her, and is instead still giving into the southwesterly shear. She seems unlikely to reach hurricane status at this point. She will be passing close enough to Bermuda to bring tropical storm conditions, and may brush New Foundland as well as she merges with an extratropical low. Both of these areas can deal with a weak tropical storm, and hopefully no one will be endangered too much by this storm. She shouldn't be too big of a deal.

Looking ahead...We're still on the lookout for mischief in the Caribbean next week or beyond. Right now the area is dead because Maria is sitting north of it, but after she leaves and cold air envelops the eastern half of the United States, pressures should rise there and allow convergence to begin in the western Caribbean, increasing thunderstorms and precipitation there. The NOGAPS supports a storm in 7 days, but that's the NOGAPS, not very trustworthy. The GFS is alternating between showing a storm and not showing a storm, and the ECMWF has dropped significant hints at development. This is good news since we don't want a storm developing close to land, but what could be happening is that the models may be shifting the timeline back a little bit, favoring development 5 days or so later than they were before. The GFS shows the Caribbean much juicier-looking in 15 days than 8 days. The reason for this may be that without a tropical wave to stimulate development, the cool pattern over the eastern U.S. may need more time to induce low pressure in the Caribbean.

The various ensembles are also starting to hint more at a trough over New England in the 11-15 day period, which corresponds to a pattern that is seen almost every time a late-season storm develops in the western Caribbean and move north into the eastern gulf, Florida, or Bahamas area. I show a bunch of these storms in today's video and the pattern that they developed in, with similarities to the forecasted pattern in 10-15 days. The time period for development may be shifting out to the 20th through the 30th instead of 15th through 25th, but a 5-day shift isn't that bad for how long we've been talking about this. This is still a very long way out and we'll just have to watch this pattern to see if stuff starts to bubble in the Caribbean.

We shall see what happens!

NHC Official Forecast for Tropical Storm Maria:



Tropical Storm Maria Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






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Maria still struggling; West Caribbean and SW Atlantic to host mischief next week

By: Levi32, 4:29 PM GMT on September 13, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Tropical Storm Maria continues to struggle with wind shear, and remains lopsided. The new trough ahead of her may both help and hinder her by both ventilating and shearing her, so she may strengthen a little bit, but it may be too hard for her to even reach hurricane status. We will have to see. Either way, she will not be a huge deal. She may make a close enough pass to Bermuda to generate tropical storm conditions there, and she may brush New Foundland on her way out as well, but for both areas she will not be a horrible storm.

The eastern Atlantic will continue to be monitored for future development, as some new tropical waves will be coming off in a few days that may try to stir up trouble.

The next concern for development close to land will be the pattern for next week that I have been talking about for a long time now. The models are starting to at least periodically support my idea that we will see tropical development in the western Caribbean area sometime next week. The base reasoning for this remains the same. We will all be hearing about the record cold over the central-eastern U.S. over the next several days. This cold is raising surface pressures in the areas that have seen low pressure all summer. We know from experience that when big highs move over New England that we have to watch south of them for tropical mischief. The result of this is that air will start converging into the western Caribbean for the first time in a while, and with the eastern Pacific dead quiet, there will likely be monsoonal support with no competition from the Pacific side. Thus, the cards seem to be stacked for development.

The models are having a hard time picking up development on every run because we aren't getting it from a pre-existing disturbance like a tropical wave. In other words, this is what I have heard some people call "pattern-induced" development, where the overall pattern favors upward motion in a certain tropical region, and then development occurs, seemingly out of thin air. This is a situation that the models find hard to grasp, and that is why the GFS has been alternating from hurricanes to nothing in the 8-12 day period. The ECMWF hasn't really caught on yet but keeps hinting at it. It would be nice to get some solid model support for this idea that I've been pushing.

The models are also hinting at home-grown mischief occurring off of North Carolina in this pattern south of the New England high, and this is a possibility. We will have to see if a development farther north tries to steal the show from the Caribbean, or whether we get two different developments. I still think the Caribbean will try to fire something up either way. We shall see. Overall, this is a pattern under which people should be watchful to the south and east of the SE U.S. coast, because tropical development is likely to be at least attempted sometime next week, and it could move northward to affect the coastline.

We shall see what happens!

NHC Official Forecast for Tropical Storm Maria:



Tropical Storm Maria Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






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Maria not a big deal; Caribbean about to light up

By: Levi32, 4:32 PM GMT on September 12, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Tropical Storm Maria is now north of Puerto Rico and remains sheared due to a combination of fast trade winds and an upper low to her north. She will be recurving out west of Bermuda as expected and shouldn't be a big deal for anyone, though she could potentially bring weak tropical storm conditions to the Canadian Maritimes. She may make a run at hurricane status northeast of the Bahamas, but will probably get knocked down again when she moves over Katia's cold water wake southwest of Bermuda. Either way, she likely won't be a landfalling storm and will recurve out to sea similar to Katia.

The GFS shows development of a Cape Verde wave in 3-5 days, so we will be watching for that.

The next big worry though comes from the Caribbean in 8-12 days. As I have been talking about, the pattern supports mischief in the western Caribbean during the 3rd week of September, which we are now closing in on, next week. The guts of the reasoning for this idea haven't changed since I first started talking about it 9 days ago, and the root of this problem stems from the cold outbreak over the southern and eastern United States. Things will be turning very cold again in 3-4 days across the parts of the country that were hot all summer, and some records may be broken. All this means is that the air is getting denser and air pressures will be rising over areas that have had abnormally low pressures all summer. The cold water left by Irene, Katia, and Maria will also contribute to higher pressures over the western Atlantic. All of this will force air to converge over the Caribbean, supporting thunderstorm activity, ultimately culminating in the development of low pressure next week. I think we will get a storm out of this pattern.

The path of such a storm would be limited to either west into Central America, or north into the central-eastern gulf, Florida, or Bahamas areas. The Texas ridge is forecasted to be forced south into Mexico for a time, but this will still tend to block northwesterly movement towards the western gulf. We still have a long time to watch for development in the Caribbean, and we're likely still 8-10 days away from anything significant happening. It will be exciting for me to see if this actually verifies, but of course we will be hoping that we don't get a dangerous cyclone out of it.

We shall see what happens!

NHC Official Forecast for Tropical Storm Maria:



Tropical Storm Maria Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






Updated: 6:47 PM GMT on September 12, 2011

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Nate taking Option #2 into Mexico; Watching Maria; More trouble down the road

By: Levi32, 3:41 PM GMT on September 09, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Tropical Storm Nate put on a little show yesterday, a rather surprising one, and got down to 995mb with 70mph winds, almost technically a hurricane, although he looked nothing like one. Dvorak satellite estimates were still at 35kts at the time, a weak tropical storm. This intensification was likely in part due to the curvature of the coast of the Bay of Campeche, which likes to help wind up small systems. However, Nate has been full of dry air for a couple of days now, and thus he got capped yesterday and has weakened some overnight, now likely a moderate tropical storm with very weak thunderstorm activity. He may also be cooling the water beneath him due to the fact that the warm water is very shallow in the southern BOC, and thus he is probably negatively impacting himself by remaining stationary in the same area for so long.

The models are now very bunched up on a WSW track into Mexico, and at some point when the models agree enough they are 99% of the time going to be correct about the overall motion. Thus, Nate is likely to take the option #2 that was mentioned yesterday as being the 2nd most likely track outside of a move towards Louisiana. This is obviously a bad forecast, but at least I was correct that the middle option, with a track towards northern Mexico/southern Texas, was ridiculous and was highly unlikely, and the track would be either north or WSW. The NHC was forecasting this 3rd option yesterday, and it didn't turn out so well for them, as their forecast has shifted 300-400 miles from yesterday. This was a difficult storm to forecast, but it's one we can learn from. I show in the video why I was wrong on Nate's path, so I can avoid that mistake next time.

This southern track makes Nate more likely to be a potent storm moving into Mexico, and I could see him trying to approach Cat 1 status once he moves over warmer water farther west if he can overcome the dry air around him, as he is fairly symmetrical, but Cat 1 will still be hard to attain, and I don't think he will reach Cat 2 like the 5am NHC forecast (edit: 11am forecast stays Cat 1). However, Mexican residents should closely monitor this system, as small storms can wind up in a hurry in the BOC, as we have seen many times before.

Tropical Storm Maria I think I will end up being correct on, unlike Nate. She looks "better" this morning in that she has a large area of intense thunderstorm activity, but her circulation is elongated and ill-defined based on recon data. She will likely keep moving WNW towards the general area of Puerto Rico and the Virgin Islands, and should be a solid moderate tropical storm in that area. Based on her appearance this morning alone, I would think that folks there in the Antilles should be expecting nasty weather for the next couple of days. Thereafter, Maria should continue northwestward and end up just northeast of the Bahamas in a few days. She will probably try to become a hurricane in this area, but may get knocked down later if she moves over the cold water wake left by Hurricane Katia. The models are mostly in agreement on my idea that Maria should recurve east of the United States, despite getting fairly close to the Bahamas. Again, the main reasoning for this is that a big Canadian trough has to come rescue ex-Lee's cut-off upper low over the central U.S., and as a result, a big upper trough will be in place to turn Maria out next week.

Looking ahead....I am still voicing concern over the period of September 15th to September 25th for the Caribbean, southern gulf, and Bahamas areas. With the southern U.S. cooling off, and the southwest Atlantic cooling off due to hurricanes, activity should get focused in the Caribbean as air is forced to rise, and we should get a storm there around the 3rd week of this month. Some ensembles are starting to hint at low pressure in the western Caribbean in 10 days, so we will be watching for more models to start latching on to this idea.

We shall see what happens!

NHC Official Forecast for Tropical Storm Nate:



NHC Official Forecast for Tropical Storm Maria:



Tropical Storm Nate Model Track Forecasts:



Tropical Storm Maria Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






Updated: 3:44 PM GMT on September 09, 2011

Permalink

Nate unlikely to get very strong; Maria likely to miss the U.S.; More trouble coming

By: Levi32, 3:00 PM GMT on September 08, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

Find me on Youtube          Find me on Facebook (also on Twitter)



Tropical Storm Nate continues to spin away in the Bay of Campeche, moving painfully slowly northeastward. The storm looks very dry, with a low-level cloud deck showing up everywhere but the southwest quadrant of the system, which is the only quadrant that has deep convection in it. I never bought the NHC idea that the extremely dry air northwest of Nate was not affecting him, and I think it is getting entrained directly into his circulation. This should keep Nate weak for much of his life, as this dry mid-level flow off of Texas into the gulf is forecasted to remain in place for the next few days without letting up. Wind shear will also be on the increase as Nate gains latitude, due to ex-Lee's old upper trough over the southern United States.

Yesterday I became more uncertain about Nate's track due to most of the models shifting away from my track to the northern gulf coast. I don't like being a "50/50 guy," and although there are times when we need to wait and see, having an already named storm in the Gulf of Mexico is an unacceptable time not to have a solid forecast. In the video today I give 3 good reasons why Nate should still move into the north gulf coast instead of into Mexico. This is not to discount a Mexico track entirely, and folks there should definitely keep an eye on Nate, but I find it the least likely of our two main options. A track in the general direction of the Mississippi River makes sense here, into the same general areas that were hit by Lee, though perhaps slightly farther east. Nate shouldn't strengthen a whole lot, and I'm not yet sold on the NHC forecast for Nate to become a hurricane. At this time I don't see him being able to become any stronger than a moderate tropical storm in the face of the extremely dry air and moderate wind shear that he will be dealing with.

Tropical Storm Maria has an exposed center this morning, as wind shear has increased from the light values that were in place yesterday. An upper low northwest of Maria is contributing a little bit to the shear, but most of it is being caused by strong surface trade winds which were in place north of Maria yesterday, and as her center moved into the faster stream, it yanked her surface center out from under the rest of her circulation. This is the kind of shear that results from strong surface winds, as opposed to strong upper-level winds. This, along with some dry air, should keep Maria a tropical storm as she moves through the lesser Antilles and the Puerto Rico area, and a hurricane seems unlikely. Folks there should be preparing for a tropical storm. Later, Maria will likely become a hurricane as she moves just northeast of the Bahamas, and for that reason, the Bahamas should keep an eye on Maria as well. I still feel that Maria will recurve east of the United States due to a strong upper trough over the eastern seaboard next week. It is too soon to stop watching Maria here in the U.S. though, and she shouldn't be ignored.

Looking ahead....I still think the period of September 15th to 25th should see a storm somewhere in the NW Caribbean, southern Gulf of Mexico, or Bahamas area, for reasons discussed in earlier posts. Some ensembles are starting to show hints of this idea in 10-15 days, and I think we will see some long-range models start to latch on. I'm putting myself out on a limb with a 2+ week forecast, but the pattern supports activity in this area, and such activity could easily threaten the Caribbean islands, Bahamas, central America, or the gulf coast down the road.

We shall see what happens!

NHC Official Forecast for Tropical Storm Nate:



NHC Official Forecast for Tropical Storm Maria:



Tropical Storm Nate Model Track Forecasts:



Tropical Storm Maria Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






Permalink

Watching 96L; How do you solve a problem like Maria? Easy - throw a trough at her

By: Levi32, 4:56 PM GMT on September 07, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

Find me on Youtube          Find me on Facebook (also on Twitter)



Hurricane Katia continues to weaken and will pass on the most harmless path possible, right between Cape Hatteras and Bermuda, and then well south of the Canadian Maritimes on its way northeastward.

Invest 96L is the most immediate concern for the U.S., sitting in the southern Bay of Campeche. This system may try to develop into a weak tropical storm over the course of the next few days, but it is unlikely to get very strong due to extremely dry air to its northwest, caused by upper convergence on the back side of ex-Lee's upper trough. This trough is also imparting southwesterly shear on the Gulf of Mexico, which will also limit 96L's intensification. The air is so cold and dry that you can actually see small cumulus cloud streets north of 96L due to cool air moving over warm water, similar to what you would see in the winter, which is quite amazing for the first week of September. 96L will likely move northward slowly towards the weakness from ex-Lee's trough, and may eventually approach the north gulf coast. A hook to the left into Mexico is also possible if the trough tries to leave 96L behind, especially if it remains a weak system. We will be hoping for such a hook to occur near the Mexico/Texas border so that south Texas might get some rain, but with such weak steering currents it is hard to know for sure if a left hook will occur.

Now, we must figure out how to solve a problem like Maria. Tropical Storm Maria is 2-3 days from impacting the northern Leeward Antilles Islands and Puerto Rico. Maria looks decent but nothing like a rapidly strengthening storm, and there are outflow boundaries to the southwest of her circulation, indicating that she is struggling with some dry air. The current downward MJO pulse is likely contributing to sinking motion over the central Atlantic, and this may be one reason why none of the models are strengthening Maria before reaching the islands. Due to these conditions ahead of her, Maria will likely continue to struggle with dry air and may not even be able to become a hurricane before reaching the islands, though it's not impossible that she could. I would be prepared regardless in the leeward islands, and since Irene just recently came through, hopefully preparations will go quickly there.

Maria should then start curving to the northwest, likely missing the Bahamas. I'm going to go out on a limb and say that I think Maria is likely to miss the United States entirely. Solving a problem like Maria is easy. Just throw a trough at her. The upper trough associated with ex-Lee will be stuck over the central U.S. for the next 5 days or so, and the only way it's going to escape is if it gets rescued by a big trough from Canada. Such a trough should come down in 5-7 days and phase with Lee's old trough over the eastern U.S. before taking it out. This means that a big trough will have to be in place over the eastern U.S. at some point during the next 6-10 days. As a result, Maria should be recurved out to sea between Cape Hatteras and Bermuda by this trough. The only two ways she could hit the U.S. in this pattern are either to pass into the heart of the Caribbean instead of north of it, or to wait 7-8 days before crossing 70W. Neither of these possibilities seems likely right now. While it is not impossible for Maria to be a problem for the U.S., I think it is more likely that she misses.

The next real problem may come after Maria in the northwestern Caribbean, southern Gulf of Mexico, or Bahamas area, because everything is cooling down north of this region. The eastern U.S. is under a cold spell right now, and storms like Irene, Katia, and Maria are cooling the waters north and east of the Bahamas. All of this acts to force convergence and upward motion in the Caribbean, which, combined with a quiet eastern Pacific, supports activity flaring up in there between September 15th and 25th.

We shall see what happens!

NHC Official Forecast for Tropical Storm Maria:



Tropical Storm Maria Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






Permalink

Katia no big threat; We will have a problem like Maria; Nate's coming too

By: Levi32, 5:00 PM GMT on September 06, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

Find me on Youtube          Find me on Facebook (also on Twitter)



Hurricane Katia put on a show yesterday and made it to Cat 4 with a clear eye, which has since disappeared. Another eyewall replacement cycle was stimulated by dry air entrainment, and Katia is another example of how storms this year are struggling when they get large due to below-normal atmospheric instability across the global tropics. Katia will pass between Cape Hatteras and Bermuda as we have talked about, and should be no significant threat to anybody, which is awesome. Bermuda and Cape Cod should be aware of gusty winds and high surf, but that's about it.

Next we're going to have to solve a problem like Maria. It's either going to be in the Gulf of Mexico or from invest 95L in the central Atlantic. We will talk about the gulf first because it is the most immediate threat. In short, Lee had a tail, and that tail is sticking down towards the Yucatan. At the tail of this tail is a small area of low pressure that the models develop in a few days. This system is most likely to come northward into the weakness left by Lee and affect the north gulf coast. Some models try to take it westward into Mexico, and this is still a possibility, but I believe it is not as likely. There may be some wind shear over the gulf during this time that could limit the system's intensity, and overall the models aren't too excited about strengthening it rapidly. We will have to watch it closely as it will be a threat.

Out in the central Atlantic we have Invest 95L, which looks rather nice today with a nearly closed surface circulation, and it may become a tropical depression today or tomorrow. This will be Maria if it beats our gulf system. True to its name, it will be a problem, as it will be heading WNW towards the lesser Antilles islands. The good news is that the models don't want to strengthen 95L much before reaching the islands, but given how nice it looks now, I wouldn't bank on that idea just yet. Folks in the islands should closely monitor this system. Obviously if 95L affects the islands, then areas farther west like the United States may have to deal with it too. The good news is that because of Lee's cut-off upper low still stuck over the center of the country, a big longwave trough is going to have to dive in over the eastern U.S. to rescue the cut-off low. Thus, we may have a big trough over the eastern seaboard next week that could recurve 95L out to sea, but that is far from guaranteed, and much depends on 95L's short-term track. The ECMWF actually brings it into the Caribbean and develops it in the NW Caribbean in 10 days. Interestingly enough, this would satisfy my requirement for a storm in that area after September 15th. However, the Euro may be confusing 95L with another low that comes up and fills that role. What may actually happen is that 95L recurves north of the Caribbean islands and lets something else come up behind it, but we will have to see. It's still too early to take a full swipe at where 95L will go. We need it to develop first so we can work out its short-term track.

And as just mentioned, I still feel that we will have a storm somewhere in the NW Caribbean, southern Gulf of Mexico, or the Bahamas area during the 3rd week of September, near or after the 15th. This could be 95L, but I have a feeling it may be something else after it.

We shall see what happens!


Official NHC Forecast for Hurricane Katia:



Invest 95L Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






Permalink

Watching Katia and Son of Lee in the short-term - Caribbean/Gulf/Bahamas long-term

By: Levi32, 4:47 PM GMT on September 05, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

Find me on Youtube          Find me on Facebook (also on Twitter)



Hurricane Katia is turning into an absolutely gorgeous storm, with a large, clear, contracting eye that is making Katia look somewhat annular, though she still has spiral bands and thus fails to meet that definition. Her outflow is excellent, and although we expected her to be a major hurricane, she may even exceed the maximum intensity of Cat 3 that I set for her. She already looks like a Cat 3 if not a Cat 4, despite the current NHC intensity of Cat 2. Katia should track right between Cape Hatteras and Bermuda as I expected, and although the fragility of the pattern has made the eastern U.S. nervous because of a few model runs, it looks like the escape out to sea that we have been talking about will occur, sparing basically everyone, which is nice. High surf and rip currents will be a concern along the eastern seaboard as Katia passes by to the east.

Lee is starting to leave the north gulf coast behind, but he has a tail sticking down into the Gulf of Mexico that the models say will try to develop near the northwestern Yucatan Peninsula in 3-5 days. Such a feature would be under weak steering currents, but would likely drift NNE towards the north gulf coast. Conditions don't look to favor anything strong, but we will keep an eye on the area for more mischief from the son of Lee.

Next in line we have a couple of tropical waves behind Katia, the 2nd one being invest 95L, a nice-looking wave with very recognizable rotation on satellite imagery. The models aren't too hyped up about this wave, but keep it as a defined entity as it moves WNW towards the Caribbean islands in a favorable environment, and thus it should be watched very closely. An even bigger concern may be the next feature that comes up right behind 95L and probably makes it into the northern Caribbean or the Greater Antilles in 10-15 days. The ECMWF is now joining the GFS in hinting at trouble in the western Caribbean after the 15th of September, as we have been discussing for the last couple of days. I explain again in the video today how the U.S. cooling off for the next week charges the country with air that starts piling up in the Caribbean, clashing with monsoon southwesterlies out of the Pacific, to create an environment that favors development of any tropical wave that gets in there. I think we will have a storm moving into the area of the NW Caribbean, southern Gulf of Mexico, or the Bahamas during the 3rd week of this month. Yes that is two weeks from now, but I think this pattern favors such an event. We'll see how it verifies. Such a storm would take one of two general tracks, either west into central America and Mexico, or north into the central-eastern gulf, Florida, or the Bahamas and SE U.S. area. I think a move to the north into the mean weakness over eastern North America is likely here, but it is still a long way off.

We shall see what happens!

Official NHC Forecast for Hurricane Katia:



Hurricane Katia Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






Updated: 4:58 PM GMT on September 05, 2011

Permalink

Lee stronger and making landfall sooner; Katia a concern for Bermuda; Looking ahead

By: Levi32, 4:47 PM GMT on September 03, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

Find me on Youtube          Find me on Facebook (also on Twitter)



Tropical Storm Lee made a little jump reformation northward closer to the Louisiana coast last night, and is thus already nearing landfall, sooner than anticipated. Exactly when landfall occurs is still fuzzy, and it should be tonight, but the storm could try to hug the coast as late as through tomorrow morning. It won't make too much difference either way. Lee has strengthened to 992mb with 60mph sustained winds, so the landfall intensity forecast was good here. The general track idea of north and northeast into Louisiana for the end-game also turned out decently. Despite 60mph winds, water will be the big story with Lee, and over a foot could fall during the next 3 days over parts of southeast Louisiana and Mississippi, bringing significant flooding to some areas, which people should be prepared for. Lee will be crawling northeast or ENE over the central gulf states for the next couple of days before being slowly accelerated NE up through the eastern U.S. by a shortwave trough.

Hurricane Katia continues to struggle, and hasn't strengthened. Eventually she should overcome some of the dry air and shear affecting her and be able to become a Cat 2 or 3 hurricane, but that should be the cap on her lifetime maximum intensity. I still feel that Katia will pass between Cape Hatteras and Bermuda, which is the thinking I have had since Tuesday. The models are focused just west of Bermuda this morning, with the exception of the lousy UKMET which has really failed on Irene and now Katia as well. While it is always wise to watch a storm until it is physically passing you, I wouldn't worry too much on the U.S. east coast. The pattern should take Katia out. The same trough that is pulling Lee northward will be picking Katia up as well, and some of the ridging generated by Lee to his east that we talked about may also be helping to give Katia the boot. Bermuda may have to watch this storm closely, as well as potentially the Canadian Maritimes in the long term.

Looking ahead...I show in the video why the western Caribbean really hasn't had a significant storm so far this season, and how the pattern responsible for that is momentarily changing for the next week or two, charging up southeastern North America with air that may try to converge down into the Caribbean and help spin up a storm after September 15th. With the MJO returning and the GFS hinting at mischief there, it is something to keep an eye out for, as it would make sense given the pattern.

We shall see what happens!

NHC Official Public Advisory for Tropical Storm Lee:

ZCZC MIATCPAT3 ALL
TTAA00 KNHC DDHHMM

BULLETIN
TROPICAL STORM LEE ADVISORY NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL AL132011
1000 AM CDT SAT SEP 03 2011

...LEE APPROACHING ATCHAFALAYA BAY...HEAVY RAINS...STRONG GUSTY
WINDS...AND POSSIBLE TORNADOES LASHING SOUTHEASTERN LOUISIANA...


SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...29.3N 91.8W
ABOUT 45 MI...75 KM SW OF MORGAN CITY LOUISIANA
ABOUT 65 MI...100 KM S OF LAFAYETTE LOUISIANA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...N OR 5 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...993 MB...29.32 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* ALABAMA/FLORIDA BORDER WESTWARD TO SABINE PASS TEXAS...INCLUDING
THE CITY OF NEW ORLEANS...LAKE PONTCHARTRAIN...AND LAKE MAUREPAS

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* ALABAMA/FLORIDA BORDER EASTWARD TO DESTIN FLORIDA

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...INCLUDING POSSIBLE
INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY
YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1000 AM CDT...1500 UTC...THE CENTER OF TROPICAL STORM LEE WAS
LOCATED NEAR LATITUDE 29.3 NORTH...LONGITUDE 91.8 WEST. LEE IS
MOVING TOWARD THE NORTH NEAR 6 MPH...9 KM/H. A SLOW AND POSSIBLY
ERRATIC MOTION TOWARD THE NORTH OR NORTH-NORTHWEST IS EXPECTED
DURING THE NEXT 24 HOURS...FOLLOWED BY A GRADUAL TURN TOWARD THE
NORTHEAST. ON THE FORECAST TRACK...THE CENTER OF LEE IS EXPECTED
TO CROSS THE LOUISIANA COAST LATER THIS MORNING OR EARLY
AFTERNOON...THEN MOVE SLOWLY ACROSS SOUTHERN LOUISIANA TONIGHT
AND SUNDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 60 MPH...95 KM/H...WITH HIGHER
GUSTS. SOME FLUCTUATIONS IN STRENGTH ARE POSSIBLE THIS AFTERNOON
AND EVENING...WITH GRADUAL WEAKENING FORECAST TO OCCUR ON SUNDAY.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 230 MILES...370 KM
FROM THE CENTER. A SUSTAINED WIND OF 49 MPH...80 KM/H AND A GUST TO
54 MPH...87 KM/H WERE RECENTLY REPORTED AT THE NOAA BUOY LOCATED
ABOUT 50 MILES EAST OF THE MOUTH OF THE MISSISSIPPI RIVER...AND A
WIND GUSTS TO NEAR 60 MPH HAVE BEEN REPORTED IN THE NEW ORLEANS
METROPOLITAN AREA THIS MORNING.

A STORM SURGE OF 4 FEET WAS RECENTLY REPORTED AT SHELL BEACH
LOUISIANA. A SURGE HEIGHT OF 3.5 FEET HAS BEEN REPORTED IN LAKE
PONTCHARTRAIN AT NEW CANAL STATION...AND A SURGE HEIGHT OF 2 FEET
HAS BEEN REPORTED AS FAR EAST AS PASCAGOULA MISSISSIPPI.

RAINFALL AMOUNTS UP TO 7 INCHES HAVE OCCURRED THUS FAR ACROSS
PORTIONS OF SOUTHEASTERN LOUISIANA.

THE MINIMUM CENTRAL PRESSURE RECENTLY REPORTED BY AN AIR FORCE
RESERVE RECONNAISSANCE AIRCRAFT WAS 993 MB...29.32 INCHES.


HAZARDS AFFECTING LAND
----------------------
RAINFALL...TROPICAL STORM LEE IS EXPECTED TO PRODUCE TOTAL RAIN
ACCUMULATIONS OF 10 TO 15 INCHES OVER SOUTHERN LOUISIANA...SOUTHERN
MISSISSIPPI...AND SOUTHERN ALABAMA THROUGH SUNDAY NIGHT...WITH
POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 20 INCHES. THESE RAINS ARE
EXPECTED TO CAUSE EXTENSIVE FLOODING. RAINFALL AMOUNTS OF 4 TO 8
INCHES WILL BE POSSIBLE OVER THE FLORIDA PANHANDLE THROUGH SUNDAY
NIGHT.

STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS
3 TO 5 FEET ABOVE GROUND LEVEL ALONG THE LOUISIANA COAST...AND BY AS
MUCH AS 2 TO 4 FEET ABOVE GROUND LEVEL ALONG THE MISSISSIPPI AND
ALABAMA COASTS INCLUDING MOBILE BAY. SEE PRODUCTS ISSUED BY LOCAL
NATIONAL WEATHER SERVICE FORECAST OFFICES FOR MORE DETAILS.

WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO CONTINUE OVER
PORTIONS OF THE WARNING AREA TODAY.

TORNADOES...A FEW TORNADOES WILL BE POSSIBLE THROUGH TONIGHT OVER
PORTIONS OF SOUTHERN LOUISIANA...SOUTHERN MISSISSIPPI...SOUTHERN
ALABAMA...AND THE FAR WESTERN FLORIDA PANHANDLE.


NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORY...100 PM CDT.
NEXT COMPLETE ADVISORY...400 PM CDT.

$$
FORECASTER STEWART

NNNN

Official NHC Forecast for Tropical Storm Lee:



Tropical Storm Lee Model Track Forecasts:



Official NHC Forecast for Hurricane Katia:



Hurricane Katia Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






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TD13 likely to threaten Louisiana as at least a strong tropical storm; Watching Katia

By: Levi32, 4:53 PM GMT on September 02, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

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Tropical Depression #13 is meandering very slowly in the northern Gulf of Mexico as it organizes. The system has improved greatly since yesterday, with a well-defined circulation now and a pressure of 1004mb. Buoys and oil rigs are reporting sustained winds up to 45kts, so I don't know why the NHC hasn't named this Lee yet, but regardless, it will be Lee at some point today. An upper low over southwest Louisiana to the northwest of the storm is still imparting some shear, but not as much as yesterday as it has been pushed a little farther out of the way. However, it is still responsible for TD 13's lopsided look with most of the convection off to the eastern side. This may remain an issue for TD 13 for the next couple days, as this upper low won't be leaving entirely, and may maintain the storm's lopsided look by limiting outflow and convection on the western side. This should restrain the system's intensification, and thus a hurricane is still unlikely before the weekend is over, as we talked about yesterday. If TD 13 finds itself still over water on Monday, then we may be talking about a Cat 1 hurricane, but if he moves ashore before that, then probably not.

The models have come around to the ideas we discussed yesterday about TD 13 eventually having to move northeast into Louisiana as the end-game track, after perhaps meandering over the NW gulf for a few days before that. It remains to be seen whether there will actually be a loop in the track like my forecast yesterday had, but such loops are hard to forecast, and the general idea is that TD 13 has been tracking to the NW, but it will be stopped before reaching Texas, and then get redirected northeastward into Louisiana due to a weakness induced by an upper shortwave trough moving across the northern plains. I feel confident in this forecast now as the models are starting to support it, along with the first couple NHC tracks. TD 13 will be a very slow mover, and the exact timing of when it makes landfall will determine how strong it gets. The NHC has landfall occurring Sunday morning. I like the idea of closer to Sunday night for actual landfall, but it's difficult to make a confident forecast on the timing in a weak steering situation like this. Some of the models still have TD 13 over water on Monday, which could allow it to become a hurricane. If landfall occurs on Sunday, I think a strong tropical storm of 60-70mph winds is likely.

It is possible that if the storm sits very close to the coast for a day or two that it could upwell some colder water in the shallow shelf areas near the coastline, thereby weakening itself. This would only be an issue if TD 13 sits within 50 miles of the coast for a long time, as the rest of the Gulf of Mexico has such deep warm water that upwelling shouldn't be an issue for a tropical storm or Cat 1 hurricane.

The big story with this storm won't be winds though, but rain. The very slow movement of this system means that southern Louisiana is going to get drenched with over a foot of rain in places. Some of these areas are in drought, but this would be too much water all at once, and flooding is a big concern here. Folks along the north gulf coast from Louisiana to Alabama should be prepared for a strong tropical storm or minimal hurricane making landfall, and tropical storm conditions could spread into the Florida panhandle as well.

Hurricane Katia is back to hurricane status, after the expected downgrade yesterday, and should gradually begin to strengthen again, eventually moving up to a Cat 2 or 3 hurricane in a few days. She continues to chug on WNW, and I still expect a track right between Cape Hatteras and Bermuda, eventually out to sea fairly harmlessly. However, Katia is still worth watching for the eastern seaboard, as a couple of models and some of the ECMWF ensembles indicate a track into the Bahamas that could threaten the United States. The pattern is still a dangerous one as we have been talking about, and thus such a possibility can't be dismissed, but I still think Katia will spare the US. I wouldn't lose any sleep over it, as the storm is still many days away from being a threat, but it is worth keeping an eye on. The same goes for Bermuda.

Invest 94L is a random swirl in the north Atlantic that nobody cares about. It may or may not get named at the whim of the NHC.

We shall see what happens!

NHC Official Public Advisory for Tropical Depression #13:

ZCZC MIATCPAT3 ALL
TTAA00 KNHC DDHHMM

BULLETIN
TROPICAL DEPRESSION THIRTEEN ADVISORY NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL132011
1000 AM CDT FRI SEP 02 2011

...DEPRESSION NEARLY STATIONARY SOUTH OF THE LOUISIANA COAST...
RAINBANDS MOVING ACROSS MUCH OF SOUTHEASTERN LOUISIANA...


SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...27.3N 91.5W
ABOUT 190 MI...310 KM SW OF THE MOUTH OF THE MISSISSIPPI RIVER
ABOUT 230 MI...370 KM SE OF PORT ARTHUR TEXAS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 2 MPH...4 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* PASCAGOULA MISSISSIPPI WESTWARD TO SABINE PASS TEXAS...INCLUDING
THE CITY OF NEW ORLEANS...LAKE PONTCHARTRAIN...AND LAKE MAUREPAS

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN THE
NEXT 24 HOURS.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA ...INCLUDING POSSIBLE
INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY
YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1000 AM CDT...1500 UTC...THE CENTER OF TROPICAL DEPRESSION
THIRTEEN WAS LOCATED NEAR LATITUDE 27.3 NORTH...LONGITUDE 91.5 WEST.
THE DEPRESSION IS DRIFTING TOWARD THE NORTHWEST NEAR 2 MPH...4 KM/H.
A CONTINUED SLOW AND POSSIBLY ERRATIC MOTION TOWARD THE NORTHWEST
OR NORTH IS EXPECTED TODAY AND SATURDAY. ON THE FORECAST TRACK...
THE CENTER OF THE CYCLONE IS EXPECTED TO APPROACH THE COAST OF
SOUTHERN LOUISIANA DURING THE WEEKEND.

MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/H...WITH HIGHER
GUSTS. GRADUAL STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS
AND THE DEPRESSION COULD BECOME A TROPICAL STORM LATER TODAY. WINDS
OF TROPICAL STORM FORCE ARE BEING REPORTED ON OIL RIGS NORTH AND
EAST OF THE CENTER AT ELEVATIONS OF A FEW HUNDRED FEET.

THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON REPORTS FROM NEARBY
OIL RIGS AND AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT IS 1005
MB...29.68 INCHES.


HAZARDS AFFECTING LAND
----------------------
RAINFALL...THE DEPRESSION IS EXPECTED TO PRODUCE TOTAL RAIN
ACCUMULATIONS OF 10 TO 15 INCHES OVER SOUTHERN LOUISIANA...SOUTHERN
MISSISSIPPI...AND SOUTHERN ALABAMA THROUGH SUNDAY...WITH POSSIBLE
ISOLATED MAXIMUM AMOUNTS OF 20 INCHES. THESE RAINS ARE EXPECTED TO
CAUSE EXTENSIVE FLOODING.

STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 2
TO 4 FEET ABOVE GROUND LEVEL ALONG THE NORTHERN GULF COAST IN AREAS
OF ONSHORE FLOW.

WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO FIRST REACH THE
COAST WITHIN THE WARNING AREA THIS EVENING...MAKING OUTSIDE
PREPARATIONS DIFFICULT OR DANGEROUS.

TORNADOES...ISOLATED TORNADOES ARE POSSIBLE OVER PORTIONS OF
SOUTHERN LOUISIANA TONIGHT.


NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORY...100 PM CDT.
NEXT COMPLETE ADVISORY...400 PM CDT.

$$
FORECASTER STEWART

NNNN

Official NHC Forecast for Tropical Depression #13:



Tropical Depression #13 Model Track Forecasts:



Official NHC Forecast for Hurricane Katia:



Hurricane Katia Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






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93L a headache - could be a big deal; Katia struggling but could threaten Bermuda

By: Levi32, 3:27 PM GMT on September 01, 2011

Please note that these tidbits do NOT reflect the official forecasts of the National Hurricane Center, and should not be taken as such. While tropical cyclones exist in the Atlantic, the official NHC forecasts will be posted in the lower part of this blog. Please refer to those when making decisions, and heed the advisories and evacuation statements of your local National Weather Service Office.

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 with the video, and please feel free to ask me any questions regarding what I talk about in these tidbits, or about the weather in general. You can post in either of my blogs or on Youtube. I will do my best to answer. Thanks for stopping by!

Find me on Youtube          Find me on Facebook (also on Twitter)



The video went kind of long today, but there is a lot to talk about. Invest 93L is going to be a headache for forecasters this weekend and early next week, as it will likely meander around the northwest Gulf of Mexico for a few days before moving inland. A move straight NW into the heart of Texas is unlikely due to the ridge there, and a deflection either WSW or northeast along the periphery of the ridge is likely. The big question is which direction will it choose and when will it choose it. A shortwave trough moving into the eastern U.S. in 3-4 days will try to tug 93L northeast, but it may or may not succeed. I ramble about a lot of stuff in the video regarding the pattern, but the main point is that much is going to depend on how strong 93L is and how it influences its own environment. 93L's strongest outflow channel is going to be to the southeast towards the NW Caribbean during its life, and if it strengthens substantially into a strong storm, that outflow will help strengthen the ridge to the southeast of 93L, between itself and Hurricane Katia to the east. This ridge would then increase the southwesterly steering flow over the Gulf of Mexico, and thus 93L would help propel itself northeastward into Louisiana. Because I think 93L has a chance to get fairly strong while sitting over very hot water for 4-5 days, I think the eventual end-game will be a northeast move into the Louisiana/MS area, after an initial loop to the WSW off the Texas coast and then back northward. This forecast has a larger than normal amount of uncertainty due to the complex pattern involved with weak steering currents, and the computer models are solidly divided in half between an eventual northeast movement and a WSW movement into south Texas or northern Mexico.

The benefit from 93L may be that with several days in the NW gulf it is sure to bring coastal Texas at least some showers periodically, which would be welcomed by many. However, if 93L doesn't move inland quickly this weekend, that kind of time over the 31C waters of the gulf could allow it to strengthen significantly, and a hurricane would be likely if 93L is still over water come Monday. This is the concerning part of this situation. The ECMWF shows a worst-case scenario by having 93L miss the first trough and sit still in the NW gulf for 8 days, strengthening into a major hurricane before moving into Louisiana in response to a 2nd trough. While the Euro is the outlier showing this solution, it illustrates the fragility of this pattern and just how hard it is going to be to make 93L go anywhere. Don't be surprised if my track forecast has to change during the coming days, and everyone along the gulf coast from northern Mexico to the western Florida panhandle should keep a very close eye on 93L.

Hurricane Katia is finally eating too much dry air this morning, and she may no longer be a hurricane for the moment, as her low-level center is nearly exposed. Eventually she should overcome this and strengthen again, but probably not beyond Cat 3 during her lifetime. The models still point at Bermuda, and although I still think the track will shift west between Bermuda and Cape Hatteras, folks on that island should keep a close eye on Katia. An eventual move up towards the Canadian Maritimes as a weakening tropical storm could occur as well. Chances of affecting the U.S. are slim right now, especially if we have Lee in the Gulf of Mexico after this weekend, as the ridge that he should build between himself and Katia would help force her northward as well.

We shall see what happens!

Invest 93L Model Track Forecasts:



Official NHC Forecast for Tropical Storm Katia:



Tropical Storm Katia Model Track Forecasts:



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 Potential (green areas represent upward motion associated with the MJO):






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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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MesoWest NERRS METEOROLOGICAL SITE AT KAC AK US
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Elevation: 32 ft
Temperature: 53.0 °F
Dew Point: 51.0 °F
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Wind Gust: 3.0 mph
Updated: 3:30 AM AKDT on July 31, 2014
Overlooking Peterson Bay
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Temperature: 47.0 °F
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Humidity: 95%
Wind: 3.0 mph from the WNW
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Updated: 2:54 AM AKDT on July 31, 2014

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