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 Acemmett90:
lol they didnt ban me


But your comment just got removed. :)
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Quoting CanesfanatUT:


who you work for? I'm wit' XOM - steam crackin' expert.
Ascend, formerly Solutia, formerly Monsanto.
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Quoting DestinJeff:
GFS 2.0 has the low sort of adrift in the BOC... only thru 48hrs

Link


Same exact position it had it at that time frame on the 6z run.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
the Admins are watiching i see
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Starting tomorrow the 18Z model cycle may be a little better, additional upper air obs.


000
NOUS74 KEHU 271900
ADASRH

ALERT ADMINISTRATIVE MESSAGE
NATIONAL WEATHER SERVICE SOUTHERN REGION HEADQUARTERS
200 PM CDT SUN JUN 27 2010

TO: ALL SOUTHERN REGION OFFICES

FROM: SOUTHERN REGION HEADQUARTERS REGIONAL OPERATIONS CENTER

SUBJECT: SPECIAL SIX HOURLY UPPER AIR OBSERVATIONS

THE NATIONAL HURRICANE CENTER HAS REQUESTED SPECIAL SIX-HOURLY UPPER
AIR OBSERVATIONS FROM THE FOLLOWING STATIONS BEGINNING AT 18Z MONDAY
IN SUPPORT OF TROPICAL DEPRESSION ALEX.

ABQ...EPZ...AMA...MAF...DRT...OUN...FWD...CRP...BRO...LZK...SHV...
JAN...LCH...SIL

SPECIAL SIX HOURLY UPPER AIR OBSERVATIONS SHOULD CONTINUE UNTIL
FURTHER NOTICE.
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I still don't see enough to convince me that GFS / CMC take on the trough is enough to bring Alex all the way to TX/AL border. It may get far enough north to miss Mexico altogether, but I wouldn't be surprised to see the Laguna Madre still be in the landfall zone.

Maybe something overnight will change to be more convincing to me....
Member Since: October 25, 2005 Posts: 19 Comments: 22087
Quoting Patrap:
GOES-East 1 km Center Relative Visible Floater


Is it just me or is that satellite positioned incorrectly?
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Quoting nola70119:
There is a pronounced smell of oil in the air in New Orleans. This is consistent with steady winds from the South....its going to move oil onto the coast this weekend.


Really Bad Uptown here today. Worst smell yet..and now a T Storm is a Booming thunder.

WUnderful..
Member Since: July 3, 2005 Posts: 424 Comments: 128269
Quoting DestinJeff:


"Work/rest cycles" are commonplace, at least in the AF during garrison ops.


Just to add to that Coast Guard is the incident commanding group for this and the flag standard is from what the Coast Guard put out and what OSHA strictly enforces. The temps here at that beach have been at 100+ with heat indexes reaching 120+ most days have had no wind. Today was the first day we have had a bit of wind.
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913.

Im amazed that you havent been banned.
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GOES-East 1 km Center Relative Visible Floater
Member Since: July 3, 2005 Posts: 424 Comments: 128269
Quoting AllBoardedUp:
I didn't mean to sound sarcastic. I don't know the logistics of off shore drilling or their clean up activities, but I know do know that on shore that shutting down a chemical plant or refinery can take a few days. The time span from shutting down and getting back up to full rates can sometimes be 2 weeks. At my plant alone, it is several millions of dollars a day. There are over 200 plus plants in the greater Houston area, this doesn't include the plants from Corpus Christi to New Orleans. They are trying to balance a decision between shutting down prematurely but still shutting down in time to do it safely and letting their personnel take care of their homes, etc. I do understand your concern though.


who you work for? I'm wit' XOM - steam crackin' expert.
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Alex really has good symmetry and looks very healthy for a storm that just spent a day over land. I think he is trouble once he gets away from land.
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Quoting Stormchaser2007:


I highly doubt that.
Don't be so doubtful. If Alex takes a more easterly track towards Louisiana there is a rather high chance that Alex will be stronger than a category 2 hurricane. Not saying it will, just giving my opinion.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting kmanislander:


Pressure makes the winds


Yes

But they base intensity off of winds not pressure. Though most of the time the winds will catch up to the pressure since the pressure drives winds.
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lol..nice
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Member Since: July 3, 2005 Posts: 424 Comments: 128269
There is a pronounced smell of oil in the air in New Orleans. This is consistent with steady winds from the South....its going to move oil onto the coast this weekend.
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Quoting Stormchaser2007:


Winds make a storm, not pressure.


Winds are a difference in pressure, that pressure stayed at 999mb, would not be shocked to see the winds go up and Alex become a TS again tonight
Member Since: March 10, 2010 Posts: 1 Comments: 7683
The 18z GFS stalls and bombs out Alex east of south/central TX.

(StormVista)
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I thank God that Alex isn't going near the oil!! Now I just hope that all of the storms this year will miss the oil....
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Quoting PanhandleChuck:


Didn't mean to strike a nerve, I just believe that we (everyone) are a long way off from figuring out the behavior of TC's. No hard feelings.


its all good, if this wasd a done deal we would all be doing something else with our sunday
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Quoting Stormchaser2007:


Winds make a storm, not pressure.


Pressure makes the winds
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Quoting Gumbogator:
Alex only 9 MBs from a hurricane. The models are split with a crawling large system. Get da dart board out(w/track). We're getting an enhanced seabreeze rain because of Alex/feeder bands!!
There is a very large discrepancy in pressure and wind speed. Even if there is a pressure of 910mb but there are winds of 50mph, it is a TS regardless.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
906. jpsb
Quoting charlottefl:
You have to kind of anticipate that, we are still possibly 5+ days out from a landfall. And while track errors have improved in the 5 day forecasts, they are still very large. Anything beyond 72 hours anyways is low confidence.

Agreed, I feel safer when 5 days out I am the target. A little worried when 3 days out I am the target and very worried at 24 hours, at 12 hours I panic (cat 4/5). lol.
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Quoting btwntx08:
personally think its a south tx event just like dolly in 08



yup me too but this time may be this a TAD more S
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Quoting Gumbogator:
Alex only 9 MBs from a hurricane. The models are split with a crawling large system. Get da dart board out(w/track). We're getting an enhanced seabreeze rain because of Alex/feeder bands!!


Winds make a storm, not pressure.
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Quoting WinterAnalystwx13:


I think its a central TX event just like Ike of 2008.


I highly doubt that.
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Alex only 9 MBs from a hurricane. The models are split with a crawling large system. Get da dart board out(w/track). We're getting an enhanced seabreeze rain because of Alex/feeder bands!!
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almost there another little bit
Member Since: July 15, 2006 Posts: 171 Comments: 53820
Looks like Brownsville.
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Quoting Levi32:
18z GFS a little farther west than the 12z in 66 hours.

It is also stronger than before.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
RECON en route
Member Since: July 3, 2005 Posts: 424 Comments: 128269
Trough is strong, but not that strong to pull Alex, or erode the ridge enough for a strong ELY heading at all. Don't see this getting any further E than a TX/LA landfall, and that may be pushing it.
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Quoting ATL:

Are they using respirators? 10 on, 50 off seems a bit extreme to me. Also, are you guys getting the crude odor like Patrap mentioned? I have some family down there and they say the tourist industry is shot.


this is hubby. right now pcola beach does not have the smell. Most of the oil is weathered but still toxic to ingest or touch. we have not been wearing respirators but we have been wearing tyvek. we have right now 3 shifts running 24 hours that is approx 2000 workers streching from destin to the state line. the numbers are increasing everyday. Just keep us in your prayers and tell others not to protest us. We are not BP!!! We the people from these communities, that found a way to serve our Gulf Coast try our best make a living for a while at this.
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Quoting Stormchaser2007:
Wow 997mb. GFS keeps making Alex stronger with each run.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
This WV image shows a SW to NE flow approching. You may have to reduce your screen size to 75%.
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Quoting Levi32:
The 18z GFS initialized perfectly, not too far north at all.


Yeah I agree, it was right on track.
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Quoting ATL:
So is recon flying tonight?


They are flying right now.

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Quoting txag91met:
Way north...not around the center.


Take a look at the vis shot. You can see that same band feeding in to the center from the N

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18z GFS a little farther west than the 12z in 66 hours.

Member Since: November 24, 2005 Posts: 635 Comments: 26647

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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.