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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3588. emguy
Quoting xcool:


xcool...What I see on your satellite loop looks like a ridge over Alex at the uppse levels (lets just guess 200mb), an Upper level low/trough over western gulf (lets just guess 500mb), and some weak...WEAK ridging in the north Gulf at about 850mb level.

Hmmm, NHC wonders why HWRF and GFDL maintain weak systems to the coast, there may be a shear environment those models are considering if Alex plowed that direction. Otherwise, Alex gets deep, I suspect paths of less resistance at a deeper level, but I sure hope not!
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Quoting sarahjola:
is alex dying?



Hmmmmm..interesting question
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3585. xcool
Joanie38 i posting in 3mins
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is alex dying?
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Quoting xcool:
:0


Whats with that face xcool?? What is going on???
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3581. xcool
:0
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Quoting SykKid:


Your username suits you well.


if only you knew what i knew. too bad i can't tell ya.
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According to the NHC, the Danger Zone includes the area from Brownsville,TX to The Mouth of the Mississippi. I totally agree. Anybodys guess, 70% Texas, 30% Louisiana, That's just my opinion..
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3573. Joanie38 1:28 AM CST on June 28, 2010

Quoting prairiewxwatcher:


Glad to see some agreement on it, thanks. The trough should steer Alex to the North further than the current NHC forecast is showing. Models have progressed northwards over the past 24 hours a fair amount, so that's been taken into consideration, extrapolating trends, etc. But then again, things could change.



How FAR north???
----------------------
Well, I'd say that all depends on how much the trough can actually steer Alex. I wouldn't be surprised if the model consensus actually pushed north a little more. But I'm not thinking Galveston/Houston, maybe Corpus Christi? We'll have to see how Alex moves today to make any real forecasts on the direction.
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3576. Hattie
boy...its late and may be I am seeing things, but it looks like Alex is being pulled apart if you run the loops....
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my confidential weather modification source says "Alex" is
going to be hit very hard with track alteration and unexplained
weakening to be expected. [laughs]

also that "ALEX" will not be allowed to hold any status above CAT1.

I am told landfall will be south of Brownsville right at the Mexican Border
possibly wed evening is my info.

a scenario similar to Dolly but further south and much weaker.

it will be interesting to see if this information pans out.

i have seen enough weather modification of hurricanes in the atlantic
in the last few years to make me a believer though.




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3574. xcool
prairiewxwatcher image you shows
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Quoting prairiewxwatcher:


Glad to see some agreement on it, thanks. The trough should steer Alex to the North further than the current NHC forecast is showing. Models have progressed northwards over the past 24 hours a fair amount, so that's been taken into consideration, extrapolating trends, etc. But then again, things could change.


How FAR north???
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Quoting xcool:
prairiewxwatcher wow



Joanie38 7:Gulf of Mexico Infrared Satellite


What do you mean exactly by wow, xcool?
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Patrap "I think I swallowed a gnat. Is that a bad sign?"

No... but if you've swallowed a spider to catch that gnat, you may have some problems...
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From looking at the NASA satellite, I looped 30 frames and the only movement I could see was a slight NNE movement. Yes, north-northeast. That's not the start of a trend. That's just Alex's center bouncing around, following the heaviest thunderstorms that blow up around the center. Other than that, movement has been almost nil.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
Quoting btwntx08:

i pretty much agree with that


Glad to see some agreement on it, thanks. The trough should steer Alex to the North further than the current NHC forecast is showing. Models have progressed northwards over the past 24 hours a fair amount, so that's been taken into consideration, extrapolating trends, etc. But then again, things could change.
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The models are still kinda wishywashy....IMO
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3566. xcool
Joanie38 .I WAS JUST POSTING
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Member Since: September 22, 2005 Posts: 11 Comments: 2032
Quoting xcool:
prairiewxwatcher wow



Joanie38 7:Gulf of Mexico Infrared Satellite


What about it?
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Quoting btwntx08:

today is pretty much the last time the models may shift and if they stay similar im in for it


Today is certainly not the last day for models to shift. They could easily shift 200 miles from where they are currently. Alex is not forecast to make landfall until Thursday. Remember, the average error for the 4-5 day cone is 200-300 miles. If Alex moves further north than currently forecast, he won't be making landfall on Thursday. It would more than likely be Friday, possibly early Saturday.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
This morning, models are in tight agreement on a landfall from Northern Mexico, to Southern Texas. Those in Southern Texas start preparations tomorrow and no later, please. I can't emphasize how serious the situation could get. Alex might have enough time and water to become a Major Hurricane, NOT WRITTEN IN STONE. The anticyclone is forecast to move back to the east in response to the upper level low moving out of the northern GOM, which has been affecting Alex's movement. Tomorrow we will most likely know how north Alex gets.

My LATEST forecast based on steering maps, models, and water vapor satellite.
Photobucket
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3559. xcool
prairiewxwatcher wow



Joanie38 7:Gulf of Mexico Infrared Satellite
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Quoting xcool:
new update


WHAT update???
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My Alex Forecast 001:

TS Alex Forecast

Obviously not expecting landfall at that one point, just a centered area, between margins of error.
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3556. xcool
n.h.c go to rigth .
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Quoting btwntx08:

today is pretty much the last time the models may shift and if they stay similar im in for it


We will see...tomorrow..err today... will be an interesting one for sure!!
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Quoting btwntx08:

today is pretty much the last time the models may shift and if they stay similar im in for it
theres still time for the models to shift in either direction
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alex enters the gulf, wow how long this took.
Member Since: September 22, 2005 Posts: 11 Comments: 2032
3552. xcool
models doing a poor job what trough
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Quoting alexhurricane1991:
Right now i think alex wil make landfall from northern mexico to corpus christi but this is subject to change and this slow motion is going to complicate things even more.


Agreed!! Goodnight again for the 2nd time! LOL!! See yall in the morning!
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Morning, everyone-

Alex should start accelerating toward the NNW for the next 24 to 48 hours. A very slight increase in forward speed is occurring at the moment, just west of due north. If Alex picks up his speed and is heading in a NNW motion while he is moving at his fastest pace, a more northern track toward the Texas Coastal Bend will be higher. If Alex begins moving more NW initially then I'd be more inclined to believe a Mexico landfall somewhere. Alex is about to feel the weakness to the north caused by the trof passing by and should begin accelerating over the next 12 to 24 hours. Alex has really hurt his chances for intensification tonight since he hasn't removed himself too far from land. Tomorrow night should be a totally different story.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
3548. xcool
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3546. xcool
new update
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Right now i think alex wil make landfall from northern mexico to corpus christi but this is subject to change and this slow motion is going to complicate things even more.
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Quoting alexhurricane1991:
I agree interesting times ahead


This is what has slowed the system and with that Northward movement the trough is winning this round it will be important to monitor the motion over the next 12 hours to see if this is a trend and to look at the model runs tomorow goodnight all
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Quoting btwntx08:

thats an ouch for me


True...but we will have to wait and see if the models will shift again....
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3520 sarahjola "I'm sure people are to busy to answer my silly questions :) "

And I'm sure that comments are coming in so fast&furious that a LOT of pages gets hidden from many individual viewers' eyes cuz they're skipped over by page renewals.
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Quoting louisianaboy444:


Slowing down....wobbles to the north...you know what that means..Something is tugging this thing North or trying to anyway i think we are witnessing the beginning of the fight between the ridge and the trough
I agree interesting times ahead
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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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