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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Station 42001 (LLNR 1400) - MID GULF 180 nm South of Southwest Pass, LA

5-day plot - Wind Direction Wind Direction (WDIR): SE ( 140 deg true )

5-day plot - Wind Speed Wind Speed (WSPD): 15.5 kts

5-day plot - Wind Gust Wind Gust (GST): 17.5 kts

5-day plot - Wave Height Wave Height (WVHT): 4.3 ft

5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 7 sec

5-day plot - Average Period Average Period (APD): 4.9 sec

5-day plot - Atmospheric Pressure
Atmospheric Pressure (PRES): 29.87 in

5-day plot - Pressure Tendency Pressure Tendency (PTDY): -0.01 in ( Falling )

5-day plot - Air Temperature Air Temperature (ATMP): 84.2 °F

5-day plot - Water Temperature Water Temperature (WTMP): 85.6 °F

5-day plot - Dew Point Dew Point (DEWP): 75.9 °F

5-day plot - Heat Index Heat Index (HEAT): 93.2 °F
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I'm still going with NOGAPS. I cant see this hitting the USA.
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Quoting MrstormX:


The official track? Whos track?


Everyone on this blog is posting new projected paths on alex, the models are catching on to this as well.
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Quoting errantlythought:


Once again, check the WVs. StormW will correct me if I'm totally off, but I think the CMC and GFS are seeing a much stronger trough than what was originally forecast, and I think I've been seeing it myself. Originally it was supposed to have been pinched at new mexico, but it seems to have broken through and is already shifting the high pressure that is over the north gulf.

I dunno yet...
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It does seem to be moving a hair west of the trop forecast points but that may change soon if it takes the northerly turn some are now forecasting. If that bad boy stays more northerly things could get bad in a hurry. This thing looks like it's just getting ready to explode when it hits the BOC/Gulf.
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Quoting Jeff9641:


don't even mention BP as I am irrate at them for not getting this fixed much sooner. Infact I don't think they really know how to get this oil from leaking. I needs to be replaced!
We will help the little people so I can get my life back.
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81. LBAR
Quoting extreme236:
NHC doesn't usually do this (from the TWD):

A NEW TROPICAL WAVE WILL BE EMERGING OFF THE WESTERN COAST OF
AFRICA INTO THE FAR EASTERN TROPICAL ATLANTIC OVER THE NEXT 24
TO 36 HOURS.



I posted the loop of this wave earlier in the thread. It's a big one and has a huge circulation already. *gulp*
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Yeah, it does look like alex is starting to move north-westwards, maybe he's going to surprise us and make landfall round about eastern texas or central louisiana =0.
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Very Impressive wave coming off Africa, going to be a long season
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Quoting stormwatcherCI:



Can anyone tell me if something is brewing in the southern Caribbean ?

I mentioned it on the previous blog looks like it may actually have a spin with it, i think it bears watching. Also the center of Alex is getting ready to emerge off mainland Mexico into the warm waters of Gulf.
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I'd say another model shift to the East in the next 12-24 hours... and you will see BP scrambling to demobilize from the oil containment efforts. It will be chaos as they were previously wanting minimum 3-days notice to evac, but they may get less than 48-hours.
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Quoting WinterAnalystwx13:


Its moving WNW/NW


Looking at NHC rainbow loop it looks like it's moving west or barely north of west. Maybe it's the rainbow loop that's deceiving me...
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TD Alex is down to 999 mb.. its also about to emerge off the coast (I think it already has)
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Quoting CosmicEvents:
Thanks for the update Dr. especially in the face of a tornado warning. All I can say is ugghh. This is bad news. Even if the storm moves in another direction, as storms tend to do, this means BP will be forced to disconnect soon. We can hope something unexpected happens when the cyclone hits the water that's colder then anything it's experienced before. Maybe we'll have some shrinkage factor.
it may, but it will grow again when it encounters some 'really hot' water.
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Thanks for the update Jeff,

But of near-term concern, safe wishes on those nasty tornadic cells around you!
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Thanks for the update Dr. especially in the face of a tornado warning. All I can say is ugghh. This is bad news. Even if the storm moves in another direction, as storms tend to do, this means BP will be forced to disconnect soon. We can hope something unexpected happens when the cyclone hits the water that's colder then anything it's experienced before. Maybe we'll have some shrinkage factor.
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Quoting Hurricanes101:
Thanks for the update Dr M

ok so anyone who thought people who said TX or LA were crazy or wishcasting, what do you say now?


Who am I to disagree with dr. M. It's just a difference of opinion. It still has a long way to go for that to happen. I'm still waiting for a good explanation as to why most of the models seem to have a bias both east and north of the actual path. In the meantime, it seems comfortable to continue it's mostly west path. If there is going to be a more northerly tug, it is not likely to occur until nighttime or early morning, as Storm indicated.
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Good afternoon everyone.

All of the focus as should be is on Alex, but I just signed on the blog. What is the latest on 94L? Looking at visible satellite, a low level swirl at the surface is moving W/NW a few hundred miles east of the Central Bahamas. I still think there is a potential for that to develop next week.
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Quoting stormwatcherCI:



Can anyone tell me if something is brewing in the southern Caribbean ?
I was wondering the same thing...
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AL 01 2010062718 BEST 0 189N 907W 30 999 TD



...INITIAL CONDITIONS...
LATCUR = 18.9N LONCUR = 90.7W DIRCUR = 300DEG SPDCUR = 9KT
LATM12 = 18.0N LONM12 = 89.0W DIRM12 = 300DEG SPDM12 = 11KT
LATM24 = 17.2N LONM24 = 87.3W
WNDCUR = 30KT RMAXWD = 75NM WNDM12 = 35KT
CENPRS = 999MB OUTPRS = 1007MB OUTRAD = 240NM SDEPTH = D
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
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NHC doesn't usually do this (from the TWD):

A NEW TROPICAL WAVE WILL BE EMERGING OFF THE WESTERN COAST OF
AFRICA INTO THE FAR EASTERN TROPICAL ATLANTIC OVER THE NEXT 24
TO 36 HOURS.

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Quoting Patrap:


Hurricane Preparation 2010









Meeeep :)
Member Since: September 22, 2005 Posts: 11 Comments: 2032
Quoting tropicfreak:
WOW the track changed a lot, now N Texas coast or Louisiana


The official track? Whos track?
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http://www.ssd.noaa.gov/goes/east/gmex/loop-vis.html
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WOW the track changed a lot, now N Texas coast or Louisiana?? How??
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Can anyone tell me if something is brewing in the southern Caribbean ?
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Quoting TexasHurricane:


That 3 is about right over me.....if that was to play out.


Sorry..lol.
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Quoting RitaEvac:
TX/LA hit is about 0% this thing isn't gonna go north all the way, gotta be realistic


Once again, check the WVs. StormW will correct me if I'm totally off, but I think the CMC and GFS are seeing a much stronger trough than what was originally forecast, and I think I've been seeing it myself. Originally it was supposed to have been pinched at new mexico, but it seems to have broken through and is already shifting the high pressure that is over the north gulf.
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Still looks to be moving almost due west or barely north of west.
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Floater - Rainbow Color Infrared Loop
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Quoting RitaEvac:
TX/LA hit is about 0% this thing isn't gonna go north all the way, gotta be realistic

I'm thinking along the lines of 10%
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45. VTG
The gfs outpeformed the official track last year? That's kind of surprising.
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Quoting muddertracker:
I'd bet the BP lawyers just pooped their shorts!


Yes, and we all know they are full of it!
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Stay safe Jeff.
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www.nola.com has been on ALEX for a week like a phat tick on a tired bloodhound.

BP best get the Plan activated.

ASAP.
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TX/LA hit is about 0% this thing isn't gonna go north all the way, gotta be realistic
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Quoting Hurricanes101:
Thanks for the update Dr M

ok so anyone who thought people who said TX or LA were crazy or wishcasting, what do you say now?


That they jumped the gun and were doing so with little information at the time?
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About

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