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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1688. Patrap
Quoting Tazmanian:



OMG is this thing froming a eye


Keep your eye on this one Taz.

Its going to take all of us to school the next 48.


Member Since: July 3, 2005 Posts: 428 Comments: 129904
1687. IKE
Quoting Tazmanian:



OMG is this thing froming a eye


Pinhole?
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Quoting Tazmanian:
is that a eye wall forming

Lol, no. It is just a feeder band.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1684. MZV
Alex's banding to the west and north keeps filling in... I'm wondering if this storm will have much of a diurnal minimum. Seems ripe to keep stengthening with such low pressure and emergence over water.
Member Since: July 3, 2008 Posts: 0 Comments: 227
http://www.ssd.noaa.gov/goes/flt/t1/vis-l.jpg

Alex is wrapping around himself, meaning it is strengthening.
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Quoting MiamiHurricanes09:
LOL! And every single time I was first and you were second.


:( *tear drop*
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1681. guygee
Looking at that center fix and eyeballing the NHC forecast points on the floater, Alex might be slightly right of track, but not by much.
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is that a eye wall forming

Member Since: May 21, 2006 Posts: 5091 Comments: 115456
1679. Levi32
Quoting stillwaiting:
looks like alexes LLC is slightly not aligned w/ the mlc,the sat and recon show this well...


Recon overlayed on visible satellite shows it perfectly lined up.

Member Since: November 24, 2005 Posts: 635 Comments: 26701
1678. Patrap
Floater - Rainbow Color Infrared Loop
Member Since: July 3, 2005 Posts: 428 Comments: 129904
The center (per hh data) seems to be a little north of the official track as of 4pm. Looked like a slight jog norht on last couple frames. Ramping up too.
Member Since: August 26, 2006 Posts: 0 Comments: 1548
Quoting MrstormX:


The official track? Whos track?


My track hasent changed much from yesterday..I should of
Quoting Weather456:


cat 2


Depends on how far north it makes landfall...
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Quoting Patrap:



OMG is this thing froming a eye
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
1673. angiest
Quoting MZV:


I kind of disagree with that rule. Dean and Felix made beelines to the west. Ike curved a little but that was a fairly western-headed storm too.

The conditions drive things, but I do think exceptionally large storms are harder to forecast. We see fewer of them and they have less background data for modeling.


Thanks for reminding people. :) I havent been on here since just after Ike, but I definitely remember all the people who kept saying Ike would never come here because he was too strong and too far north. Can't believe people are still saying that. Statistically it might be the case that strong storms move north, but it i s not something on which to make plans. My rough guess at the moment is anyone west of Mobile should keep a close eye on things, but any storm in the Gulf should be watched by anyone along the Gulf coast.
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Quoting pipelines:
does anyone have a loop of Ike coming into the gulf from Cuba? I would like to compare the structure/intensification of Ike to Alex at these similar times as I think it will tell us a lot about what Alex may be undergoing. Ike also dropped in pressure after entering the gulf at a fairly fast rate but due to Ike's large size and other unknown variables, it mostly increased the size of the wind field instead of wind speed.
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Quoting Clearwater1:
Am I to understand that the MX Government will not allow our hh to fly over land for some reason. Yet they rely on our weather service for hurricane recon. Or am I overreacting?
AFAIK, recon doesn't fly over land anywhere....
Member Since: October 25, 2005 Posts: 19 Comments: 22736
looks like alexes LLC is slightly not aligned w/ the mlc,the sat and recon show this well...
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1668. Levi32
Quoting victoriahurricane:
I really think NHC made a mistake in downgrading the system to a tropical depression, probably thinking it's over land, it has to weaken, but it actually strengthened. This never looked at any point in time with his trek over the yucatan any less then a tropical storm and I doubt it fell below that status.


Was not a mistake....winds always fall way behind the pressures in a storm that travels over land due to friction. You can see 960mb hurricanes get downgraded to Cat 1 after landfall with the same pressure.
Member Since: November 24, 2005 Posts: 635 Comments: 26701
1666. Patrap
Member Since: July 3, 2005 Posts: 428 Comments: 129904
Quoting F4PHANTOM:
If that is center cord. ,then he went WSW from previous coordinates.19.2N to 90.9N and 90.9W to 91.5W.


dont read too much into that, Alex is still moving WNW to NW
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First of all, I am seeing Alex moving into N Mexico and if the US is affected it would be S Texas.

I do not see this storm moving into LA or N Texas because:

1) The Beta effect will be strong

2)anticyclonic steering the storm NE

3) the trough lifts out in 3-4 days and its most southern proximity is 32N

4) the strong ridge over the CONUS.

5) GFS and CMC ridiculous
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Quoting Baltimorebirds:
Alex may very well be a moderate tropical storm in my opinion.


It has the pressure and winds. The winds are lagging the pressure the HH has found but there is little doubt that Alex should be upgraded soon.
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Quoting F4PHANTOM:
If that is center cord. ,then he went WSW from previous coordinates.19.2N to 90.9N and 90.9W to 91.5W.
It could be that the NHC just had the wrong COC location.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
I wonder when this blog is gonna start going nutz?? LOL!
Member Since: June 16, 2008 Posts: 0 Comments: 507
the pressure falls along the upper gulf coast today...that high has weeked...yesterday 30.03, today 29.80
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Quoting Weather456:


I expect rapid intensification (deepening), if any, to occur after 36 hrs where ocean heat content is highest. For now, a drastic increase in winds (rapid strengthening) would be the result of the positive feedback to the low pressure, nothing more, nothing less.


And if there is positive feedback from the low which would probably intensify the system, it could feel the ridge then and move more north, right?
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I don't know but I think the inner eye wall is forming this time before the outer eye wall.
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Alex is an omen of things to come, but not the main event, yet, at least not for the US part of the Gulf. Mexico could very well get a solid Cat 3, but I think the bigger story of Alex is that he's the first one out of the gate.

At first I was bearish on Alex but he did suddenly have a circulation that went from non-existent to simply enormous in a very short period of time. I would expect a Cat 5 to have that kind of breadth of circulation, not a piddly tropical storm. Darby looked puny comparatively, at least on satellite imagery.

Imagine there was not Cuba/Hispanolia and no Yucatan. Alex would have been as big as the Gulf by the time he entered it. DISCLAIMER: At least, that's how it looked to a non-met like me.
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Quoting MZV:


I kind of disagree with that rule. Dean and Felix made beelines to the west. Ike curved a little but that was a fairly western-headed storm too.

The conditions drive things, but I do think exceptionally large storms are harder to forecast. We see fewer of them and they have less background data for modeling.

Well thats just the typical saying. But every storm is different.
Member Since: August 2, 2006 Posts: 0 Comments: 1240
Quoting RecordSeason:
1569:

They are the same in principle once they get going, but the manner in which they form is not necessarily the same.

"Alex" formed from a massive tropical wave(93L,) which absorbed several other tropical waves back when it was in the eastern and central Caribbean.

I gotta tell you, I was watching the whole time, and there was some FREAKY oscillations of convection going on back then on the color enhanced infrared.
Thank you! I thought they were exactly the same thing only in different parts of the world. Much appreciated.
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does anyone have a loop of Ike coming into the gulf from Cuba? I would like to compare the structure/intensification of Ike to Alex at these similar times as I think it will tell us a lot about what Alex may be undergoing. Ike also dropped in pressure after entering the gulf at a fairly fast rate but due to Ike's large size and other unknown variables, it mostly increased the size of the wind field instead of wind speed.
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According to the location of the lowest pressure, Alex's COC is located at:

19.1˚N 91.0˚W
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1650. Patrap
Member Since: July 3, 2005 Posts: 428 Comments: 129904
1649. Levi32
Quoting GainesvilleGator:
Is it Weather456 predicting a N Mexico landfall and Alex will NOT hit Texas?

I think it is premature to be dropping landfall locations for Alex. 3-4 days out there is always a large forecast error spread. This could hit N Mexico but then again it is not wise to rule out other possibilies. Dr. Masters always thows out percentages such as: 70% change of hitting XXX and 30% change of hitting XXX ext.


I hate percentages.....I usually give a section of coastline where I think landfall is likely to occur if it is uncertain and several days out. Yesterday morning I came out and said I thought this would hit Mexico near 25N, and I'm sticking to that for now. Otherwise, people should keep in mine that there is still a lot of uncertainty and there are possibilities for Alex to hit a number of different places. One can never be absolutely certain about a landfall in a situation as fragile as this.
Member Since: November 24, 2005 Posts: 635 Comments: 26701
I really think NHC made a mistake in downgrading the system to a tropical depression, probably thinking it's over land, it has to weaken, but it actually strengthened. This never looked at any point in time with his trek over the yucatan any less then a tropical storm and I doubt it fell below that status.
Member Since: October 16, 2008 Posts: 0 Comments: 544
Quoting Baltimorebirds:
What's the strongest you think alex can get?.I'd say a minimal cat 3 storm is not out of the question.


Don't make me say that "K" word!
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Quoting Baltimorebirds:
What's the strongest you think alex can get?.I'd say a minimal cat 3 storm is not out of the question.


cat 2
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1644. MZV
Quoting alaina1085:

Exactly right. The stronger the storm the more north they go. Weaker the more west.


I kind of disagree with that rule. Dean and Felix made beelines to the west. Ike curved a little but that was a fairly western-headed storm too.

The conditions drive things, but I do think exceptionally large storms are harder to forecast. We see fewer of them and they have less background data for modeling.
Member Since: July 3, 2008 Posts: 0 Comments: 227
Quoting RitaEvac:
Until I see this kind of movement, I aint worrying



Intresting, bret skipped cat 3 status and it went straight from 2 to 4
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Quoting tropicfreak:


Lets not even think about that. its bad enough when its partially over land and other half over water, but in the open, I can't even imagine how powerful or monstrous it would be.


We will have to in a couple of hours.
Member Since: May 27, 2009 Posts: 0 Comments: 4438
A center fix using reccon data

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am looking for word too what this thing looks like in the AM
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
Quoting HurricaneSwirl:


Ok this is the second or third time today we have posted nearly the exact same thing at the exact same time. We've gotta stop that LOL
LOL! And every single time I was first and you were second.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Levi32:


Wouldn't describe it as pinhole....just a small eye, and yes it did develop one. It strengthened over land which was quite a site to see for those of us who were awake to witness.
Fay all over again man, lol.
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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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