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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but where is the center of this thing, I would have thought with those coordinates they have passed they would have hit it by now
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Quoting nrtiwlnvragn:


Overreacting. They avoid flying over land in a storm at 2000 feet, possibility of turbulence.
Oh, that make sense. Thanks for clearing that up for me.
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991.6mb and they are still not at the center fix. Alex will likely have sub-990.0mb pressure when they reach the circulation.
Member Since: September 2, 2009 Posts: 130 Comments: 21109
1535. amd
this is very similar to Hurricane Opal which had winds of 40-45 mph when it emerged from the Yucatan as a Tropical Storm, but had a pressure in the 980s.

Looks like winds with Alex are about 35-40 mph, but pressure is in the low 990s. Frankly, I'm surprised at the low pressure, and not in a good way.

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Quoting MiamiHurricanes09:
No contamination there buddy.


In that case wow, obviously winds haven't caught up though.
Member Since: May 27, 2009 Posts: 0 Comments: 4438
I stepped away for a minute, came back and checked recon data before I checked the blog.. imagined in my head for a bit what the blog would look like, came to the blog, and the two images were exactly the same XD
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting Levi32:
This, to me, indicates that Alex was easily a Cat 1 hurricane before landfall in the Yucatan. Or....he was a strong TS at landfall and strengthened into a hurricane over the eastern Yucatan....he formed an eye northwest of Belize while inland....an incredible feat. He appears to have strengthened over land last night like TS Fay did over Florida.


I was expecting Alex to maintain strength and even weaken a little, never would I have thought that it would strengthen over land, let alone strengthen to a hurricane.
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Quoting Levi32:
This, to me, indicates that Alex was easily a Cat 1 hurricane before landfall in the Yucatan. Or....he was a strong TS at landfall and strengthened into a hurricane over the eastern Yucatan....he formed an eye northwest of Belize while inland....an incredible feat. He appears to have strengthened over land last night like TS Fay did over Florida.


Read my thoughts, that is exactly what must have happened. Alex is already adapting quickly to the Gulf of Mexico per satellite images.
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Quoting muddertracker:
We can fly over Cuba..we have an agreement or something..can't fathom why we wouldn't be able to fly over Mexico!



A few post made mention "that since they can't fly over land so they will not be able to fly into the coc" got me to wonder why? I know about Cuba, but MX?
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1526. Levi32
Very close to the center where that 991mb reading was found.

Member Since: November 24, 2005 Posts: 635 Comments: 26594
Quoting alaina1085:

I dont know about you, and I know alot of people say since this is more the typhoon type storm rapid intensification is rare...but I think Alex is out to prove something!
Indeed. Once the winds catch up with pressure Alex could be a strong tropical storm.
Member Since: September 2, 2009 Posts: 130 Comments: 21109
1524. ATL
I gotta question that reading...but seeing as there are others that are nearly as low I'll sit back and watch the excitement.
be like Ike, has a low pressure but winds no where close in speed for a pressure like that, so big can't create the wind speed for the pressure
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1522. Makoto1
And with that the blog explodes. This is definitely stronger than the NHC thought.
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Quoting tropicfreak:


About time you came back, i do believe the senior met StormW could use a little help from another great expert.


I've been here since about Saturday morning...
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Quoting MiamiHurricanes09:
Alex is definitely impressing me right now. WOW.

I dont know about you, and I know alot of people say since this is more the typhoon type storm rapid intensification is rare...but I think Alex is out to prove something!
Member Since: August 2, 2006 Posts: 0 Comments: 1240
Quoting MrstormX:


Just saw that, Holy crap Miami... contamination?
No contamination there buddy.
Member Since: September 2, 2009 Posts: 130 Comments: 21109
1518. Levi32
Quoting CybrTeddy:
991 mb..

No way this things a Tropical Depression.


I'd say it's a TS but its winds are nowhere close to the 60-65 knots that you usually see with a 991mb system. That is because it just passed over land....but a 991mb center means the winds will quickly reach 60 knots within the next 24 hours if Alex successfully reorganizes and tightens up a new core.
Member Since: November 24, 2005 Posts: 635 Comments: 26594
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?


Overreacting. They avoid flying over land in a storm at 2000 feet, possibility of turbulence.
Member Since: September 23, 2005 Posts: 14 Comments: 11053
1515. angiest
Quoting alaina1085:

Although the winds dont prove that pressure now, we all know what happens after a pressure drop... the winds will catch up. I think Alex has a few suprises up his sleeve.

Ike's winds didn't catch up with his pressure, but the storm still did damage closer to the what the pressure indicated than the winds.
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Quoting Weather456:
Peak surface winds by reccon thus far is 35 mph
The winds will soon catch up with the pressure, not a good sign considering the 991mb reading.
Member Since: September 2, 2009 Posts: 130 Comments: 21109
When the winds catch up to the pressure readings they're getting, this thing will be a minimal hurricane at least.
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Hi again all..I have a question..any opinions appreciated...Our local met was saying something about a front approaching that will steer Alex AWAY from SW LA....Can't this front pick it up and make it head more north?? or no?? Any thoughts? Thanks in Advance..:)
Member Since: June 16, 2008 Posts: 0 Comments: 507
Quoting Weather456:
Very robust and large circulation entering the GOM

If you notice that Alex jogged NNW on the last few frames. This occurs because of convection that built over the GOM in the NW quadrant, which storms tend to follow (right leading edge of convection)



About time you came back, i do believe the senior met StormW could use a little help from another great expert.
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Quoting MiamiHurricanes09:
Alex is definitely impressing me right now. WOW.


Just saw that, Holy crap Miami... contamination?
Member Since: May 27, 2009 Posts: 0 Comments: 4438
1509. KEEPEROFTHEGATE (Mod)
01L/TS/A/
MARK
19.5N/91.8W
Member Since: July 15, 2006 Posts: 170 Comments: 53518
1507. Levi32
This, to me, indicates that Alex was easily a Cat 1 hurricane before landfall in the Yucatan. Or....he was a strong TS at landfall and strengthened into a hurricane over the eastern Yucatan....he formed an eye northwest of Belize while inland....an incredible feat. He appears to have strengthened over land last night like TS Fay did over Florida.
Member Since: November 24, 2005 Posts: 635 Comments: 26594
OMG OMG OMG 991MB
Member Since: May 21, 2006 Posts: 5091 Comments: 114919
Quoting alaina1085:

Although the winds dont prove that pressure now, we all know what happens after a pressure drop... the winds will catch up. I think Alex has a few suprises up his sleeve.
I agree...
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Quoting Levi32:
Holy crap...991.6mb and no center yet!

000
URNT15 KNHC 272343
AF304 0401A ALEX HDOB 19 20100627
233400 1947N 09110W 9242 00664 9974 +206 +134 073028 029 027 000 00
233430 1945N 09110W 9247 00657 9974 +199 +136 069029 030 030 002 00
233500 1944N 09110W 9254 00650 9971 +209 +136 074029 029 028 000 00
233530 1942N 09110W 9250 00653 9970 +205 +136 076029 029 027 000 00
233600 1940N 09110W 9248 00654 9969 +205 +138 076031 032 028 000 00
233630 1939N 09110W 9249 00651 9967 +205 +139 080032 032 028 002 00
233700 1937N 09111W 9250 00649 9965 +206 +141 083032 032 029 001 00
233730 1935N 09111W 9249 00647 9963 +209 +142 082034 034 029 000 00
233800 1934N 09111W 9249 00646 9961 +207 +144 080033 034 030 000 00
233830 1932N 09111W 9245 00646 9959 +205 +145 078034 035 031 001 03
233900 1931N 09111W 9247 00644 9956 +205 +146 074035 036 031 000 00
233930 1929N 09111W 9248 00639 9954 +202 +147 074037 038 032 000 00
234000 1927N 09111W 9249 00636 9951 +201 +147 073038 039 035 001 00
234030 1926N 09110W 9243 00633 9944 +190 +144 071040 041 035 004 00
234100 1924N 09110W 9253 00620 9940 +190 +141 071040 042 036 006 00
234130 1922N 09110W 9254 00617 9935 +199 +138 080033 036 036 004 00
234200 1921N 09110W 9248 00618 9929 +208 +136 075028 029 035 003 00
234230 1919N 09110W 9253 00610 9925 +210 +135 070024 025 033 006 03
234300 1917N 09110W 9250 00608 9921 +210 +136 061022 023 030 008 00
234330 1916N 09109W 9244 00612 9916 +216 +137 050020 022 029 006 03
$$
Alex is definitely impressing me right now. WOW.
Member Since: September 2, 2009 Posts: 130 Comments: 21109
991 mb..

No way this things a Tropical Depression.
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991.6 guys... Impressive.
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1499. jpsb
Quoting spathy:


Yes!
Its sucking in so much energy that it cant fit it all into a coherent package flow!
I could not believe that he sucked in that huge blob in EPAC! Alex is the real deal. NW puts Alex at TEX/MEX having a hard time seeing him get much north of Corpus, but still waiting to see what the west trof does.
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mbs are now lower then 1st land fall
Member Since: May 21, 2006 Posts: 5091 Comments: 114919
1497. Makoto1
Quoting Levi32:


They may have found TS-force winds because the quality control flag was not on for the 40-kt SFMR reading, meaning that they consider it to be accurate despite the light rain that was falling.


Thanks. Also 991.6... That's a shock.
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Peak surface winds by reccon thus far is 35 mph
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991? Wow
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991.6mb reading!
Member Since: September 2, 2009 Posts: 130 Comments: 21109
Quoting Weather456:
Very robust and large circulation entering the GOM

If you notice that Alex jogged NNW on the last few frames. This occurs because of convection that built over the GOM in the NW quadrant, which storms tend to follow (right leading edge of convection)



Hey 456, looks like Alex may cover the entire GOM at this rate.
Member Since: May 27, 2009 Posts: 0 Comments: 4438
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?
We can fly over Cuba..we have an agreement or something..can't fathom why we wouldn't be able to fly over Mexico!
Member Since: Posts: Comments:
1491. Levi32
Holy crap...991.6mb and not reached center yet!

000
URNT15 KNHC 272343
AF304 0401A ALEX HDOB 19 20100627
233400 1947N 09110W 9242 00664 9974 206 134 073028 029 027 000 00
233430 1945N 09110W 9247 00657 9974 199 136 069029 030 030 002 00
233500 1944N 09110W 9254 00650 9971 209 136 074029 029 028 000 00
233530 1942N 09110W 9250 00653 9970 205 136 076029 029 027 000 00
233600 1940N 09110W 9248 00654 9969 205 138 076031 032 028 000 00
233630 1939N 09110W 9249 00651 9967 205 139 080032 032 028 002 00
233700 1937N 09111W 9250 00649 9965 206 141 083032 032 029 001 00
233730 1935N 09111W 9249 00647 9963 209 142 082034 034 029 000 00
233800 1934N 09111W 9249 00646 9961 207 144 080033 034 030 000 00
233830 1932N 09111W 9245 00646 9959 205 145 078034 035 031 001 03
233900 1931N 09111W 9247 00644 9956 205 146 074035 036 031 000 00
233930 1929N 09111W 9248 00639 9954 202 147 074037 038 032 000 00
234000 1927N 09111W 9249 00636 9951 201 147 073038 039 035 001 00
234030 1926N 09110W 9243 00633 9944 190 144 071040 041 035 004 00
234100 1924N 09110W 9253 00620 9940 190 141 071040 042 036 006 00
234130 1922N 09110W 9254 00617 9935 199 138 080033 036 036 004 00
234200 1921N 09110W 9248 00618 9929 208 136 075028 029 035 003 00
234230 1919N 09110W 9253 00610 9925 210 135 070024 025 033 006 03
234300 1917N 09110W 9250 00608 9921 210 136 061022 023 030 008 00
234330 1916N 09109W 9244 00612 9916 216 137 050020 022 029 006 03
$$
Member Since: November 24, 2005 Posts: 635 Comments: 26594
This is insane.

Time: 23:33:30Z
Coordinates: 19.8167N 91.15W
Acft. Static Air Press: 926.2 mb (~ 27.35 inHg)
Acft. Geopotential Hgt: 646 meters (~ 2,119 feet)
Extrap. Sfc. Press: 997.6 mb (~ 29.46 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 77° at 28 knots (From the ENE at ~ 32.2 mph)
Air Temp: 20.8°C (~ 69.4°F)
Dew Pt: 13.3°C (~ 55.9°F)
Peak (10s) Flt. Lvl. Wind: 30 knots (~ 34.5 mph)
SFMR Peak (10s) Sfc. Wind: 24 knots (~ 27.6 mph)
SFMR Rain Rate: 2 mm/hr (~ 0.08 in/hr)
Member Since: Posts: Comments:
Quoting Weather456:
Very robust and large circulation entering the GOM

If you notice that Alex jogged NNW on the last few frames. This occurs because of convection that built over the GOM in the NW quadrant, which storms tend to follow (right leading edge of convection)



So glad to see you back blogging 456. Hope your 100% better!!

Quoting MiamiHurricanes09:
Exactly. IMO, Alex will likely regain it's tropical storm status at 11PM. But first Recon has to find the winds that suggest that.

Agreed!
Member Since: August 2, 2006 Posts: 0 Comments: 1240

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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.