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 WinterAnalystwx13:


No, its barely moving, in fact, its possible that Alex is stationary.
If it is stationary, that may slow down any intensification, being so close to land.
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Quoting MiamiHurricanes09:
It depends. What time is it?
Lol. Here they are Gro.

990-999mb steering. Continued WNW/NW motion is expected.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
2236. gator23
Quoting PanhandleChuck:
Where's O'Reilly when you need the "No Spin Zone"

looking for his audience BOOM
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Quoting IKE:


Southwest-caster! J/K



lol
Member Since: May 21, 2006 Posts: 5091 Comments: 115379
2232. IKE
Quoting Levi32:
Recon center fix reveals that Alex has made no progress since the last vortex message and may have even drifted southwest a hair.


Southwest-caster! J/K
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Alex is like a pitcher winding up for the pitch. He about to throw us a curve ball tot he outside of the plate.
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Quoting NCHurricane2009:
Yo, if you look at post 2177, that 991 mb pressure was measured at 1950 ft, right? The surface pressure would be higher than that if that is the case.
No its the extrapolated surface pressure.
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Quoting Stormchaser2007:
27/2345 UTC 18.9N 91.3W T1.5/1.5 ALEX




thats off
Member Since: May 21, 2006 Posts: 5091 Comments: 115379
I find it so amazing in almost a day the models and talk show Alex going bye bye and probably die over land... tonight it is complete opposite. Really crazy stuff!
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Quoting jlp09550:


Ahh, okay. Thanks for the info. :)


No problem at all :)
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i think Alex is from wave that what ues too be Karen
Member Since: May 21, 2006 Posts: 5091 Comments: 115379
Quoting Grothar:
Are there any recent steering current maps?
It depends. What time is it?
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Yo, if you look at post 2177, that 991 mb pressure was measured at 1950 ft, right? The surface pressure would be higher than that if that is the case.
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Quoting StormW:


Formed from the wave sitting in the Caribbean, in a monsoonal type environment. Instead of a "usual" east to west flow around the subtropical ridge, the ridge was oriented in such a fashion that we had more of a SE flow, which was weaker. This allowed for heat and moisture to build up in the Caribbean. The pattern is such, that we also had lowering pressures over the Caribbean, which took place over the course of about a week. Once 93L moved into the western Caribbean (favored by climatology), we finally got a surface circulation which became dominate, and basically sucked the energy from the mid level vorticies we saw, as well as all the built up heat and moisture. Remember, in meteorology, and I like to think especially in the tropics HEAT = ENERGY.
Thanks Storm new to the blog!!
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I think its slowing down for two reasons: tightening up of the center it seems, and a potential change in direction with a more northerly component coming.
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Believe it or not the 990.7 reading is to the southwest of the 991.0 reading. It is safe to say Alex is stationary.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
2219. eye
I thought we had a system a couple years ago that went from TD to Cat 5 in like 12 hrs or so?
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27/2345 UTC 18.9N 91.3W T1.5/1.5 ALEX
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Quoting ryanator:
After looking at the 18z gfs, it freaking looks like the models are honing in on a louisiana landfall. i hope they evacuate those oil rigs now if they haven't already. bc it is looking more and more likely that a major hurricane will be bearing down on them. Just mho.
What models are you looking at that show it honing in on Louisiana? I've been watching it..I live in sw La. Do you really think it might be coming here?
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Where's O'Reilly when you need the "No Spin Zone"
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Based on latest satellite images, alex appears to finally be winding now. Hopefully it drops down into the mexican mountains and dies like the diablo he is.
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Quoting Stormchaser2007:

They round up.

990.7 is 991
True.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
It's already gone down .3 mb from the time between their first and second passes through the center.. this thing is on the MOVE!
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2209. jpsb
Quoting VAbeachhurricanes:


just saying you can't throw it out. All the 0Z models have shifted even more north.
I agree, I'm still leaning towards tex/mex border but La is in play if the nnw comes.
Member Since: June 30, 2009 Posts: 0 Comments: 1197
I wish recon would continue to investigate the COC, I'm sure they are going to leave after the next vortex message is issued.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting HurricaneSwirl:


Thank you!

Nor is it the belly button on this fat boy.
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Quoting MiamiHurricanes09:
990mb now.

They round up.

990.7 is 991
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Quoting VAbeachhurricanes:


no that little hole is not his center, his center is north under the developing CDO


Ahh, okay. Thanks for the info. :)
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2203. Levi32
Recon center fix reveals that Alex has made no progress since the last vortex message and may have even drifted southwest a hair.
Member Since: November 24, 2005 Posts: 635 Comments: 26686
Quoting jlp09550:
Just curious.. but did Alex stumble south or something?



You are looking at a dry slot. The center is the blob to the N of that.
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Quoting jlp09550:
Just curious.. but did Alex stumble south or something?



I don't think you're looking at the right "center". I think you're looking at what APPEARS to be an eye, but it's not. I think the center is the red blob to the NE of that. Notice how many times I said think, im not 100% sure.
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2199. Patrap
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2198. xcool
TampaSpin good job .keep up
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting jlp09550:
Just curious.. but did Alex stumble south or something?



no that little hole is not his center, his center is north under the developing CDO
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2196. Hhunter
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OMG 10MB DROP TONIGHT
Member Since: May 21, 2006 Posts: 5091 Comments: 115379
Quoting HurricaneSwirl:


Ok, he strengthened while he was OVER land, what makes you think that being CLOSE to land will hold him back, haha.


According to NHC advisory-to-advisory updates, it actually weakened over land. Tropical cyclones can look organized over land, but they are actually weakening. If you ask me, Alex looked less impressive when it was over land because its powerful CDO dissipated after landfall, leaving only skeletal convective bands at the center.
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Quoting HaboobsRsweet:
991mb center...yikes.
990mb now.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting boiredfish:
Hey LPStormspotter....Shoreacres here. Please don't bring up I'ke's name.

Too early to tell, but I'm thinking Corpus to Victoria. Ridge of high pressure builds back in in time to make the westward turn, just later than currently forecast. We'd get some squally weather and much needed rain.


hey how are ya? well lets hope it goes south
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StormW or Weather456...What will happen if by tomorrow night it jump from tropical Storm to a Cat 2 hurricane? Will it go more north?... Just by looking at it... it is looking that maybe in forecast track for right know it is following the NHC but I think in strength it has the potential to blow up fast.

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Quoting Tazmanian:




990mbs??
Yup.
Member Since: September 2, 2009 Posts: 130 Comments: 21194

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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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