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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0z GFS Now Receiving Data
Member Since: May 27, 2009 Posts: 0 Comments: 4438
On the infrared Alex looks like he wants to hop right back across the Yucatan, lol!

Is the infrared loop, when taken together with the recon fixes, evidence that the mid-level circulation is getting de-stacked from the LLC?
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Quoting Patrap:
ALEX NASA MSFC viewer

Wow Pat the Ridge must be really strong, cause it looks like to me Alex is moving south on those last few frames.
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I concur that perhaps the NHC/Weather Channel needs to be somewhat more concervative.What's nice about the Blog is that we can discuss and debate the science.
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2934. ATL
Quoting Gorty:
Wait... 991 MB at 45 MPH!!??!!

I know winds can take a little while to catch up to pressure falls, but, this is more like 55-60 mph.


Because Alex is huge. It needs a lower central pressure to draw in air/energy from such a large area. Ike in 2008 was the same way.
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Nola Lawyer here is the archive for Katrina. Anybody that didn't haul butt was crazy. The NHC was very slow shifting though.


They did a much better job with Gustav.

Link
href="http://www.nhc.noaa.gov/archive/2005/KATRINA_graphics.shtml" target="_blank" onclick="if(!checkUrl(this.href)) return false;" rel="nofollow" >Link
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2932. leo305
Quoting HurricaneKing:
Link

Has anyone noticed how stretched Alex is. His inner core is fine but his bands are stretched from southwest to northeast. I dont think it would look like that unless something ie the trough is beginning to affect him.


upper level low in the gulf states is pushing on him
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2931. Patrap


Member Since: July 3, 2005 Posts: 426 Comments: 128865
2930. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
I think the HH have pretty good confidence that alex will be moving NW because the last 3 passes have been to alexes NW and I bet their sampling the enviornment ahead of alexes future track...by tomorrow morning they'll have a much better idea on landfall area IMO
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2927. scott39
Can the trough hamper developement?
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I agree the NHC is going to be very careful about predicting something to effect the oil spill. they don't want to cause a panic
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2925. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 128865
Quoting Hurricanes101:


As I said, be in their position; you have millions of peoples' lives in your hands. If you predict a 155mph hurricane to hit the area 5 days out, what do you think the reaction is going to be?

NHC has to be VERY careful what information they give out to the public


Precisely my point. This is why I am here for information, not watching TWC. I am sure they have reasons for their approach to predictions, and they are very skilled mets. But there is more at play than simply making predictions.
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Quoting Bordonaro:

The NHC depends on an array of computer models in developing their forecast tracks.

Unfortunately, forecasting the movement of a Tropical Cyclone is MUCH more complicated that tracking the movement of fronts, troughs and extra-tropical weather systems.

And IF the rest of the federal government ran as well as NOAA/SPC & the NHC, we'd have 2% unemployment and a $150 billion dollar surplus! Their is NO politics in their forecasts, period!


NHC is a government entity. So, yes, politics are involved - always. Right now, the government does not want to press the panic button - or atleast delay pressing the panic button for another day or so...LOL!
Member Since: July 17, 2008 Posts: 0 Comments: 1242
2921. Gorty
Wait... 991 MB at 45 MPH!!??!!

I know winds can take a little while to catch up to pressure falls, but, this is more like 55-60 mph.
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Link

Has anyone noticed how stretched Alex is. His inner core is fine but his bands are stretched from southwest to northeast. I dont think it would look like that unless something ie the trough is beginning to affect him.
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i have a question guys.. hope anyone can answer.. the 00Z models should be up in about 40 minutes right? thanks in advance

Matt
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2918. KEEPEROFTHEGATE (Mod)
070

URNT12 KNHC 280308

VORTEX DATA MESSAGE AL012010

A. 28/02:54:30Z

B. 19 deg 14 min N

091 deg 13 min W

C. 925 mb 606 m

D. 34 kt

E. 306 deg 24 nm

F. 057 deg 34 kt

G. 305 deg 21 nm

H. EXTRAP 991 mb

I. 21 C / 763 m

J. 23 C / 764 m

K. 18 C / NA

L. NA

M. NA

N. 12345 / 9

O. 0.02 / 3 nm

P. AF304 0401A ALEX OB 12

MAX FL WIND 47 KT N QUAD 01:39:50Z

SLP EXTRAP FROM 925 MB

;
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2917. twooks
Quoting LongGlassTube:
I don't trust anyone including the NHC with my personal safety. The NHC is sometimes very slow shifting their guidance. Katrina was certainly a prime example of this.

A Baton Rouge met named Jay Grimes went on to say that the Baton Rouge area had nothing to worry about from Katrina because it would strike so far to the east. You don't do that with a large storm in the gulf.


And Grimes was right, as far as the Baton Rouge area was concerned. Not much happened to us during Katrina. In fact, Gustav was way worse for us in the BR area than Katrina.
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2916. Patrap
ALEX remains in Neutral..Building a warm stack..slowly.

That trek across and some 6 hours of Organizing has robbed the motion vector for now.

Something will establish and the Upper lean to the NE is interesting.

Morning will shed some light on it..but that G-4 NOAA Evening flight tomorrow will be Oh so important chica's..
Member Since: July 3, 2005 Posts: 426 Comments: 128865
1. you can bet the gulf spill folks have a direct line to the nhc.
2. the nhc will be as "real" with them as they have the ability to be
3. the amount of northward motion depends in large part on how strong alex gets - stronger hurricanes tend to be steered at different atmospheric levels
4. the nhc discussion pointed out that intensity forecasts are extremely poor at 2-3 days out.
4a. i think it's extremely reasonable for them to be cautious on this.
4a1. if they start scaring the public and then turn out to be wrong, all reason falls by the wasteside and you get the boy who cried wolf thing going on.
5. they have indicated multiple times that this is a low confidence forecast

just try to imagine, for just one second, the pressure on these mets at nhc. every word is beign parsed, every recommendation they do or dont make could cost billions of dollars and many lives. they're not going to be alarmist until there is a higher level confidence that would justify doing so.
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2914. leo305
Quoting hydrus:
Might be feeling the trough.


upper level low in gulf states, may be pushing Alex and holding it from moving North, system is stacked up into the 200mb, so it can feel upper level systems, but the low is already moving away so it's influence should be short lived..
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I just want it to stay away from the oil
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Quoting Baltimorebirds:
That some people don't care when It's not affecting them.
Could mean that a lot of pple who had to work yesterday didn't have to today.
Member Since: October 25, 2005 Posts: 19 Comments: 22357
Quoting GlobalWarming:


yes, im aware of that, however, i do not think that it'll end up actually affecting it that greatly, :).


that is much more reasonable :)
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2910. emguy
I'm agreeing with the "LongGlassTube". Good comment.
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Quoting ATL:


Which "party lines" do you think the NHC follows?

The NHC depends on an array of computer models in developing their forecast tracks.

Unfortunately, forecasting the movement of a Tropical Cyclone is MUCH more complicated that tracking the movement of fronts, troughs and extra-tropical weather systems.

And IF the rest of the federal government ran as well as NOAA/SPC & the NHC, we'd have 2% unemployment and a $150 billion dollar surplus! Their is NO politics in their forecasts, period!
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Quoting NOLALawyer:
By "party line," I mean a more conservative approach.


As I said, be in their position; you have millions of peoples' lives in your hands. If you predict a 155mph hurricane to hit an area 5 days out, what do you think the reaction is going to be?

NHC has to be VERY careful what information they give out to the public
Member Since: March 10, 2010 Posts: 1 Comments: 7829
anyone got a link to a map with isobars on it? I wanna see where the COC actually is. From watching the last few floater frames it looks as if the actual center of Alex has removed itself about a dozen miles or so off the Yucatan and over water - which would account for the sudden increase in clouds over the center of the storm and the general strengthening over the last few hours or so. Anyway, if we had a map with some accurate and detailed isobars on it, then it would be minutes to figure out just what we're dealing with. Is this thing over water or no? If it's over water then any jog to the SW would take it out into the Bay of Campeche and cause more strengthening while if this thing is STILLL over land, any move to the SW would cause the storm to quickly degenerate - but that simply ISN'T happening right now so I'm betting that it IS over water and any move to the SW will be short lived as we went through that trough that's causing everyone all those headaches here in Colorado yesterday and let me tell you, it's PLENTY strong, hail, lightning, tornadoes, the whole shebang. So IF this storm organizes itself over the next 24 hours, its large enough to get influenced by that trough and pulled north - that trough wasn't anything to sneeze at, it WAS the real deal.

Also, IF Alex is looking to go vacationing in Texas, he's going to be going over the remnants of LAST year's loop current eddy - which is hanging out SE of the Texas coast. I believe Dr. Masters had a graphic detailing it when he talked - about a month ago now - of how the Gulf Stream had broken off into an eddy which is what was keeping the oil from going into the Gulf Stream proper. Anyway, that's a LOT of deep, hot water underneath a GOM that's already a giant bathtub, NO shear, big 'ole anticyclone on top of it, and a cyclone that's ALREADY the size of Texas (from one feeder band to the other.
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Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 28th day of the month at 03:08Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 304)
Storm Number & Year: 01L in 2010
Storm Name: Alex (in the North Atlantic basin)
Mission Number: 4
Observation Number: 12
A. Time of Center Fix: 28th day of the month at 2:54:30Z
B. Center Fix Coordinates: 19°14'N 91°13'W (19.2333N 91.2167W)
B. Center Fix Location: 62 miles (100 km) to the SW (227°) from Campeche, Campeche, México.
C. Minimum Height at Standard Level: 606m (1,988ft) at 925mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 34kts (~ 39.1mph)
E. Location of the Estimated Maximum Surface Wind: 24 nautical miles (28 statute miles) to the NW (306°) of center fix
F. Maximum Flight Level Wind Inbound: From 57° at 34kts (From the ENE at ~ 39.1mph)
G. Location of Maximum Flight Level Wind Inbound: 21 nautical miles (24 statute miles) to the NW (305°) of center fix
H. Minimum Sea Level Pressure: 991mb (29.26 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 21°C (70°F) at a pressure alt. of 763m (2,503ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 23°C (73°F) at a pressure alt. of 764m (2,507ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 18°C (64°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 925mb (If this vortex is from mid 1990's or earlier 925mb might be incorrect. See note.)
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 3 nautical miles
Remarks Section:
Maximum Flight Level Wind: 47kts (~ 54.1mph) in the north quadrant at 1:39:50Z
Sea Level Pressure Extrapolation From: 925mb
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2892.) Error was corrected
Member Since: May 27, 2009 Posts: 0 Comments: 4438
Quoting LongGlassTube:
I don't trust anyone including the NHC with my personal safety. The NHC is sometimes very slow shifting their guidance. Katrina was certainly a prime example of this.

A Baton Rouge met named Jay Grimes went on to say that the Baton Rouge area had nothing to worry about from Katrina because it would strike so far to the east. You don't do that with a large storm in the gulf.
The NHC believes "We can't handle the truth!"
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Quoting fsumet:


What they meant was they are throwing out the old GFS for the parallel GFS run which is further south and more in line with the GFDL and HWRF.


Check out the ensemble. It is totally scary.
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2901. 1965
Quoting GTcooliebai:
Lets see how good you pros are: anyone remembers this storm?



Allen?
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2900. Ossqss
I don't think most of you realize the impact of a Cane in the oil. It will not be pretty no matter.... Hope and pray for the best ......

Red Rain, will not be good!
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I agree with you.
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I don't trust anyone including the NHC with my personal safety. The NHC is sometimes very slow shifting their guidance. Katrina was certainly a prime example of this.

A Baton Rouge met named Jay Grimes went on to say that the Baton Rouge area had nothing to worry about from Katrina because it would strike so far to the east. You don't do that with a large storm in the gulf.
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Quoting Levi32:


Allen.


I remember Allen well, but for some reason I thought it was 1979.
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By "party line," I mean a more conservative approach.
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The "don't rock the boat until absolutely necessary" party line.
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Quoting MrstormX:


Hope people understand its an error, and aren't heading for the hills.
What's the error you guys are talking about?
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2891. hydrus
Quoting TropicalNonsense:


it will only be a MEXICAN Storm if they tamper with it.
look at how strong the trough is myfriend.

i just dont see it. possibly south texas but not Mexico.
There is always the chance it could meander out there for quite a while too.
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When will Alex break free of Champoton 19%uFFFD20'N 90%uFFFD50'W? It seems like it has been stuck near there for the past 10-12 hours, only moving .7N and .7W since 11 am EST or about 60 miles or about 5 miles per hour. How large is the COC for Alex? It still appears to be touching or close to touching the coast near Champoton as of the 11 pm EST advisory. The center is still within 35 miles of the coast if it is 19.4 N and 90.8W. Doesn't Alex need to be further away to really intensify and if it is already now, what then?
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Just watched local mets and they talked about trough breaking down the ridge allowing for a more northward tug. Also talked about a ULL over southern states keeping rain in the area and to expect feeder bands from Alex on Tues/Wed. But, no direct threat. I am in Alabama.
Member Since: July 17, 2008 Posts: 0 Comments: 1242

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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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