Alex may head north to Texas or Louisiana

By: Dr. Jeff Masters , 6:36 PM GMT on June 27, 2010

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Tropical Depression Alex has held together fairly well during its passage over Mexico's Yucatan Peninsula, and stands poised to re-intensify back into a tropical storm once it emerges from the coast tonight. Alex brought heavy rains to northern Honduras, Mexico's Yucatan Peninsula, and Belize over the weekend. It was not a good beach day in Cozumel yesterday, as 9.25" of rain fell. Cancun received 2.05" over the weekend, and Belize City received 4.57". Satellite loops show that Alex's heavy thunderstorms are mostly gone near the center, though there are some impressive bands of precipitation well away from the center. There is an upper-level high pressure system a few hundred miles west of Alex, and the clockwise flow air around this high is bringing upper-level winds out of the northwest of about 5 knots over the storm, contributing to the 5 knots of wind shear observed in this afternoon's wind shear analysis from the University of Wisconsin's CIMSS group. Sea Surface Temperatures are very warm, 29 - 30°C, and dry air is currently not a problem for Alex.


Figure 1. Afternoon satellite image of Alex.

Forecast for Alex: which model should you trust?
While the track forecast for Alex today through Monday is fairly well-assured, the longer range forecast has become highly uncertain. An increasing number of our reliable models are now indicating Alex may take a more northerly track beginning on Tuesday, with possible landfall on the Texas coast near Galveston on Friday (according to the 8am run of the GFS model) or into western Louisiana on Wednesday (the 8am run of the Canadian model.) The key question remains how Alex will react to the trough of low pressure expected to swing down over the Eastern U.S. on Monday and Tuesday. Most of the models were predicting that the trough would not be strong enough to swing Alex to the north, and several of them continue to predict this. The 8am runs of the NOGAPS and ECMWF models, for example, take Alex into the Gulf coast of Mexico 150 miles south of Texas, on Wednesday. The GFDL and HWRF models split the difference, with the GFDL predicting a Thursday landfall in southern Texas near Brownsville, and the HWRF predicting a Thursday landfall near Corpus Christi. Morris Bender of the GFDL group has just provided me the track forecast from an improved experimental version of the GFDL that shows landfall between Corpus Christi and Galveston. So which model should you trust? Last year, the best performing models at the 3 - 4 day forecast range were the GFS and the Canadian, and these are the models that are currently calling for the more northerly track towards the upper Texas coast and Louisiana. Residents of those areas should review their hurricane preparedness plans and anticipate that Alex could make landfall as early as Wednesday in their vicinity. Residents of the Mexican coast south of Brownsville should make similar plans, as Alex could just as easily hit there.

Re-intensification of Alex is likely once the center of Alex moves offshore, though this will initially be slow due to the current disorganized state of the storm and the relatively low total ocean heat content in the 100-mile-wide stretch of water on the west side of the Yucatan Peninsula. Once Alex moves more than 100 miles from the Yucatan, total heat content of the ocean increases substantially, and Alex will have the opportunity to intensify significantly. A longer time spent over water will give Alex more of a chance to strengthen, and it is possible Alex could intensify into a major hurricane if landfall is delayed until Thursday or Friday. However, Alex's intensification may be limited the farther north it gets, as water vapor satellite images show plenty of dry air over Texas that might interfere with development. Wind shear might also be an issue for Alex if it pushes far enough north, and a slow-moving storm tends to pull up cold water from the depths, limiting intensification. In short, Alex has the potential to intensify into a major hurricane, but there are plenty of roadblocks that make this only a 10% probability in my estimation.


Figure 2. Skill of computer model forecasts for Atlantic named storms during 2009. OFCL=Official NHC forecast; GFS=Global Forecast System model; GFDL=Geophysical Fluid Dynamic Laboratory model; HWRF=Hurricane Weather Research Forecasting model; NOGAPS=Navy Operational Global Prediction System model; UKMET+United Kingdom Met Office model; ECMWF=European Center for Medium Range Weather Forecasting model; CMC=Canadian GEM model; TVCN=one of the consensus models that lends together all (or most) of the above models; BAMM=Beta and Advection Model (Medium Layer.) Image credit: National Hurricane Center 2009 verification report.

Elsewhere in the tropics
A tropical wave (Invest 94L) a few hundred miles north of the northernmost Lesser Antilles Islands has been pretty much torn apart, and is no longer a threat to develop.

Next post
Wunderground's severe weather expert Dr. Rob Carver will likely be posting an update on Alex late tonight. My next update will be Monday by 10am EDT.

Jeff Masters

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Quoting txalwaysprepared:
AllBoardedUp -- A lot has been repaired and is Brand New. He'd have a lot to destroy, actually.
That is true, but I was thinking more of the Bolivar peninsula. I went over there recently and although they have don a lot of rebuilding it is desolate compared to what is used to be.
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587. xcool
trough COME FAST
Member Since: September 26, 2009 Posts: 2 Comments: 15684
586. WAHA
Update.
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ok guys, I'm wearing the F5 key out on the laptop, so will be back later. My brain needs a rest!
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Quoting Levi32:
Amazing thing about Alex is it has the structure of a Cat 2+ hurricane that made landfall last night, not a TS.
Probably due to its immense size.
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Taking a break now.
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Quoting Hurricanes101:
NHC track did not shift it appears


When is the next time NHC is expected to adjust their projected track? A shift to the north is surely expected correct?
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Alex is purely a TEXAS system.. It's moisture will combine with a boundary line across south/southeast Texas and bring heavy rains to the area promoting heavy flooding... be ready TX....
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I dont feel like a ride this early in the season
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Amazing thing about Alex is it has the structure of a Cat 2+ hurricane that made landfall last night, not a TS.
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There have been 30 kt systems with pressure just below 1000.



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Still think the Ull north of Puerto Rico working it's way to the surface. Might be a sneak attack.
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Quoting Max1023:
Soon convection should begin to fire over the LLC; we are already seeing development of feeder bands over the gulf, as well as convergence enhanced banding over the northern Yucatan. I think Alex is already a 40mph TS in rainbands over water, if this thing develops a tight inner core within 24 hours then everyone from Veracruz to NOLA could be in trouble. Remember how fast storms can intensify, even a large system like Alex could easily gain 20kt in 6 hours. As well, the TS wind radii will likely expand to 200nm+, meaning that a significant portion of the GoM could see TS winds for several days.


Looking at the New Wind/Wave propagation runs,MIKE 21 and the NAM.

Thats a good observation
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting GalvestonMedStudent:
I'm not liking the new northward trending of the models. I'm with the other Galvestonites -- we've been through enough! I'm pretty sure if we get nailed again this year, we can kiss my medical school and hospital goodbye. It was hard enough to convince the University of Texas system to pay for our damages the first time (Ike).
Amen! 14,000 employees are hard to replace.
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Quoting MrstormX:


Already, you can just tell that the storm has a northerly component, and that the model will make it hit Texas, as it is much further north than it is now, but the westerly component has not changed much.
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Afternoon all,

I was waiting to see how Alex looked as it emerges into the Gulf of Mexico before making this statement. Its got 4 out of 4 things going for it for rapid intensification:

1) Tightly defined center
2) Warm SSTs (sea surface temperatures)
3) Low Shear
4) Enhanced outflow

These are the things I look for for rapid intensifcation episodes. I would not be surprised if Alex becomes a major hurricane sooner than expected. Right now IMO, I think 50% chance of major hurricane whether it goes toward Mexico or S Texas, waiting to see if a convective burst develops over that tight center. Then, I would increase those chances of seeing Alex become a major hurricane.
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Quoting txalwaysprepared:
AllBoardedUp -- A lot has been repaired and is Brand New. He'd have a lot to destroy, actually.


Exactly. I'm still paying off the deductible for my roof and fence from Ike (plus other repairs needed that weren't covered by insurance), I don't need another setback.
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Quoting lopaka001:

Looks like it is already offshore..
The complete COC has yet to emerge completely but will likely emerge completely in just a matter of minutes.
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Quoting StSimonsIslandGAGuy:


They continued tracking it as an extratropical storm. Which did bring gale winds up the Ohio valley and west Appalachians.


Ah, I see. It would be less confusing if Wunderground mentioned that. Thanks.

-Snowy
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Quoting jpsb:
I am in San Leon, a little peninsula that juts out into Galveston bay. My dirt is 12 feet above sea level so it takes an Ike like storm to put water in my house. Alex might be an Ike like storm. Guess I'll just have to watch the intensity forecasts. I can do a TS or cat 2, cat 3 is iffy, cat4 or 5 and I'll have to pack up and go.
I live a block from a bayou. Slab is 11.5 feet about sea level. Ike lapped at my front door, but did not make it in the house. We were fortunate that it did not hit 50 to 100 miles south or we would had 3 to 4 feet of water in the house.
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Quoting lopaka001:

Looks like it is already offshore..


Well... I said that a few minute ago, so I guess I was right! :D
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Soon convection should begin to fire over the LLC; we are already seeing development of feeder bands over the gulf, as well as convergence enhanced banding over the northern Yucatan. I think Alex is already a 40mph TS in rainbands over water, if this thing develops a tight inner core within 24 hours then everyone from Veracruz to NOLA could be in trouble. Remember how fast storms can intensify, even a large system like Alex could easily gain 20kt in 6 hours. As well, the TS wind radii will likely expand to 200nm+, meaning that a significant portion of the GoM could see TS winds for several days.
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ALEX Floater - Rainbow Color Infrared Loop
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting Snowlover123:
Alex will be offshore in a matter of minutes.

Looks like it is already offshore..
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Quoting Patrap:
TCHP GOM




Depth of 26C isotherm




Sea Height Anomaly




SST



Interesting... the warmest water is in the N Gulf not the S Gulf. So really, the more time it spends heading North, the stronger it'll get.
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Quoting xcool:
WHO SAID FL
His neighbor
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I think this storm has a few tricks up its sleeve.I dont know what it is gonna do,but I think everyone should keep their eyes open.My main concern is the oil here in Alabama.And how much influence this storm will have on it.
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I'm not liking the new northward trending of the models. I'm with the other Galvestonites -- we've been through enough! I'm pretty sure if we get nailed again this year, we can kiss my medical school and hospital goodbye. It was hard enough to convince the University of Texas system to pay for our damages the first time (Ike).
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Note how that newer Vortex has shifted or lifted N the last hour.

Member Since: July 3, 2005 Posts: 426 Comments: 129093
556. WAHA
Hi all,

I can't believe how Alex looks! I'm even sure that it could strengthen to tropical storm status by this evening!
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555. xcool
WHO SAID FL
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting naplesdreamer28:
So I understand the track is obviously up in the air, but why is it my neighbor thinks FL is at risk?? I don't see it coming near here, right?
No shoudnt go anywhere near florida mexico to the louisiana texas border need to watch this carefully
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TCHP GOM




Depth of 26C isotherm




Sea Height Anomaly




SST

Member Since: July 3, 2005 Posts: 426 Comments: 129093
AllBoardedUp -- A lot has been repaired and is Brand New. He'd have a lot to destroy, actually.
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Halfway off

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Quoting StSimonsIslandGAGuy:


I've heard of a few lower than that. Hurricane Opal was classed as a 982 mb tropical depression, in Tennessee. Well after landfall, of course. So that's different.


How did Opal re-intensify to a TS, after weakening to a TD?
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So I understand the track is obviously up in the air, but why is it my neighbor thinks FL is at risk?? I don't see it coming near here, right?
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Quoting Dropsonde:
The NHC will NOT make a forecast that would frighten BP into abandoning ship until they have more agreement about it. The ECMWF is a good model and they respect that. Imagine how bad it would be if they went far north, BP began evacuating, and then the GFS, CMC, etc., switched to the south? This forecast is probably as high-stakes as the forecast of a Katrina or Andrew, only with much more uncertainty. If Alex does turn out to go north, they'll have almost their full five days.
Regardless of the BP spill the NHC is going to tell the truth even if it scares BP. The spill and the NHC are two different things, don't mix them up.
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Quoting txalwaysprepared:
Ok... going to bury my head for a while. Can't think what a Cat 2 could do here so soon after Ike. Besides, if I ignore it it will all go away and the track will shift south again :)
Don't mean this to sound humorous, but on the bright side, Alex won't have AS much to destroy if it hits the Galveston area!
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Member Since: July 3, 2005 Posts: 426 Comments: 129093
Alex will be offshore in a matter of minutes.
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Quoting LADobeLady:
Just thought I would pop out of lurkdom to say hello, season 6 of watching this blog. 2 things you can always count on.. The TWO will be posted her in a flash, no need to go to the NHC site and wait. 2. Dr Masters is the best, I faithfully read him and listen to him on WWL. radio.
Good to see you on again and just keep a close "eye" out for this thing thats for sure.....

Taco :o)
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540. jpsb
Quoting AllBoardedUp:
Aren't you actually in Baycliff? I remember chatting with you last season. I'm in Hitchcock? A lot of people on the SE coast of Texas still licking their wounds from Ike!
I am in San Leon, a little peninsula that juts out into Galveston bay. My dirt is 12 feet above sea level so it takes an Ike like storm to put water in my house. Alex might be an Ike like storm. Guess I'll just have to watch the intensity forecasts. I can do a TS or cat 2, cat 3 is iffy, cat4 or 5 and I'll have to pack up and go.
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Quoting aquak9:
DocMasters updated this blog 18 minutes ago...probably just snuck it in, and ran.


He added in the part about Morris Bender of the GFDL and the improved experimental track.
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Member Since: July 3, 2005 Posts: 426 Comments: 129093

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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