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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On a scale between 1-10, what would you say would be an Alex Impact Galveston to the Lake Charles area? Just wondering since people say, that Alex could track toward that direction. Thanks for your input.
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Quoting JeffMasters:
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.

Jeff Masters


Well, Guess we have an idea on where it is going..Thanks for the update
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Quoting JeffMasters:
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.

Jeff Masters


Thanks for the info Dr. Masters.
Member Since: November 24, 2005 Posts: 635 Comments: 26569
Follow the outer bands and moisture from Alex, this will tell u the general direction it will take, anywhere from La to the The big bend in Fl.
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Quoting JeffMasters:
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.

Jeff Masters

Wow
Member Since: August 10, 2009 Posts: 0 Comments: 64
Wow Dr M, thank you for that update
Member Since: March 10, 2010 Posts: 1 Comments: 7407
Quoting JeffMasters:
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.

Jeff Masters


Yuck.

EDIT: Thanks for the update by the way. Some interesting, but stomach turning info. Even though I don't live anywhere near there lol.
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So is NOLA and So. MS in the clear?
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Quoting kmanislander:


Suspect ??


This doesn't look too bad....but who knows. I think that's the first really decent weather station Alex has passed by since landfall.

Member Since: November 24, 2005 Posts: 635 Comments: 26569
Quoting MrstormX:
15z SREF



So another model favors Texas.

My forecast can be viewed here:

http://1.bp.blogspot.com/_RAYQNSAWCHA/TCeyzymQTxI/AAAAAAAAACU/xPFgc4spqoo/s1600/2010+Alex.bmp
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Quoting MiamiHurricanes09:
Very likely it is.


ATCF used 999mb for the 18Z data.
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425. JeffMasters (Admin)
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.

Jeff Masters
Cool pic barbamz. It looks beautiful there. I'll go out on a limb and say they serve beer at Summerfeast.
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Quoting kmanislander:


Got that number from PSU ewall here


Latest SHIPS text supports 29C.
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Quoting barbamz:
OK, while waiting for further development of Alex I risk to post this live cam picture from my german town Mainz (Rhine River). We experience a tropical summer night, so somehow blog related. Our big summerfeast is happening these days; band in my neighbourhood was just playing "Sweet home Alabama" ...
Good night to all.


That's a realy nice view. I've been to that area. Had a lot of fun. Thanks for the nice shot. Now go drink some good German beer.
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Quoting kmanislander:


Suspect ??
Very likely it is.
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Quoting FFtrombi:


Campeche airport about 30-40miles north of the center is reporting a pressure of 999mb.


Suspect ??
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Member Since: July 3, 2005 Posts: 421 Comments: 127702
15z SREF

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Quoting kmanislander:
Pressure is still good. Note the 1004 mb isobar surrounding the core.


Campeche airport about 30-40miles north of the center is reporting a pressure of 999mb.
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Floater - Rainbow Color Infrared Loop
Member Since: July 3, 2005 Posts: 421 Comments: 127702
Quoting Levi32:


Mmm little bit colder than that....but initial organization shouldn't be a problem.




Got that number from PSU ewall here
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OK, while waiting for further development of Alex I risk to post this live cam picture from my german town Mainz (Rhine River). We experience a tropical summer night, so somehow blog related. Our big summerfeast is happening these days; band in my neighbourhood was just playing "Sweet home Alabama" ...
Good night to all.
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Quoting kmanislander:


Water temp where Alex is about to exit is 29 C or approx 84 F. The depth of that heat is not great but a weak system such as Alex is now can do just fine with what is available to it for purposes of reorganizing.


Mmm little bit colder than that....but initial organization shouldn't be a problem.


Member Since: November 24, 2005 Posts: 635 Comments: 26569
Makes sense.. thanks Levi
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Quoting Patrap:
GOM TCHP



That is interesting because it would appear that the oil spill area has not heated up more than the rest of the gulf, as some had expected.
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Pressure is still good. Note the 1004 mb isobar surrounding the core.

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GOM TCHP

Member Since: July 3, 2005 Posts: 421 Comments: 127702
Quoting Torgen:


What's causing the north part of Alex to peel off and head east towards Florida? Is that part of the clockwise shear that's hitting Alex from the NW? It's crazy how that whole chunk just peels off and separates like that.


There is a lot of technical jargon, but simply when a storm breaks up, the outer bands break away from the center. They even do that in storms that are well formed. Once a storm really strengthens. It get pulled closer and tighter. Clouds still evacuate from the center though. Here is a stock picture of Hurricane Andrew which was probably at CAT 5 when this image was taken. Notice the symmetry.


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Anybody know how to post a Sat loop?
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Quoting CADZILLA:
The last time I cut back my trees we were hit by Ike the next week, I cut back my trees last week.

This will make a great story for Monday morning news.
Do us a favor, Cadzilla? Next time, cut your trees back in the WINTERTIME!!! ;-)
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Quoting neonlazer:
It seems the site has slowed down lately..i have been running this site for the last two days..


Server traffic
Member Since: July 3, 2005 Posts: 421 Comments: 127702
Quoting TxMarc71:
Hello?? Someone?? Anyone??

Why are the models so different from the 5-day forcast track??


The model consensus is still fairly close to the NHC track. Some of the models are shifting farther north and we will have to watch for this to become a trend. The NHC will likely adjust a little bit northward at 5pm.

The gray line with gray boxes is the TVCN, the consensus model which approximates the mean of all the model forecasts.

Member Since: November 24, 2005 Posts: 635 Comments: 26569
Quoting Patrap:
ESL Low Cloud Product Viz LARGE Image
It seems the site has slowed down lately..i have been running this site for the last two days..
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Quoting TxMarc71:
Hello?? Someone?? Anyone??

Why are the models so different from the 5-day forcast track??


because the models were run AFTER the last forecast track. The conditions have changed.
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Mode
Quoting TxMarc71:
Hello?? Someone?? Anyone??

Why are the models so different from the 5-day forcast track??


Models have updated. Track has not.
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ESL Low Cloud Product Viz LARGE Image
Member Since: July 3, 2005 Posts: 421 Comments: 127702
Quoting HurricaneSwirl:


Alright, well it looks like it has plenty of 60-80 to deal with.. I guess it's wait and see again to see what it does with it.


Water temp where Alex is about to exit is 29 C or approx 84 F. The depth of that heat is not great but a weak system such as Alex is now can do just fine with what is available to it for purposes of reorganizing.
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Quoting StormW:


Busy?


Thanks for the updates on your blog btw..
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Hello?? Someone?? Anyone??

Why are the models so different from the 5-day forcast track??
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Alex has been moving between WNW and NW for the last 8 hours or so, you can't base motion on a couple of frames of Sat imagery, cause a storm does not move in a straight line. It wobbles back and forth on a general heading.
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Quoting Patrap:
The Se flow into Uptown NOLA is bringing the Worst Crude smell yet over us.

That's so awful! I hope it doesn't affect your health.
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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.