Large and intensifying Hurricane Alex bears down on northeastern Mexico, South Texas

By: Dr. Jeff Masters , 2:23 PM GMT on June 30, 2010

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Hurricane Alex continues to intensify as it slowly bears down on the coast of northeastern Mexico. Brownsville long-range radar shows the spiral bands of Alex, which has dumped heavy rains of up to four inches in northeastern Mexico and near Brownsville, according to satellite estimates of rainfall. The Brownsville airport received 0.78" of rain in the hour ending at 8am CDT, and 0.61" in the hour ending at 9am CDT. Floods from Alex have already killed ten people--six in Nicaragua, and two each in El Salvador and Guatemala.


Figure 1. Snapshot of the Brownsville long-range radar showing Hurricane Alex approaching the coast.

The 7:12am CDT eye penetration of the Hurricane Hunters found a central pressure of 959 mb, a modest 2 mb drop from the reading four hours previous to that. They noted a very tiny eye, ten miles in diameter, with a gap in the northwest side. Tiny eyes like this tend to be unstable, and in the 9:05am CDT eye penetration, the Hurricane Hunters found that the inner eyewall had collapsed, and the pressure had risen 2 mb, to 961 mb. A new, much larger eye will form today as the day progresses. During these "eyewall replacement cycles", a hurricane will typically weaken a few millibars , and the strongest winds will spread out over a larger area as the hurricane conserves angular momentum. Thus, the hurricane still has about the same amount of destructive power, it is just spread out over a larger area. This tends to increase the hurricane's storm surge, but lessens the wind damage, since the extreme winds of the inner eyewall are no longer present. Satellite loops show a large, well-organized storm with increasing amounts of low-level spiral bands forming, and improving upper-level outflow. Data from last night's flight of the NOAA jet showed an unusually moist atmosphere surrounds Alex, so dry air is no longer a problem for it. It's a good thing Alex has less than a day before making landfall, or else is would be a large and very powerful major hurricane.


Figure 2. Visible light image of Tropical Storm Alex taken at 19:35 UTC (2:35 pm CDT) on June 29, 2010, by NASA's Aqua satellite. At the time, Alex was a tropical storm with 70 mph winds. Image credit: NASA.

Storm Surge
Traditionally, a storm's ranking on the Saffir-Simpson Scale--the familiar Category 1, 2, 3, 4, 5 rankings we always talk about--have also been used to quantify storm surge threat. However, large, weaker storms that cover a huge area of the Gulf of Mexico, like Alex, can generate a larger storm surge than a smaller but more intense hurricane with a higher Saffir-Simpson rating. Thus, the National Hurricane Center has formally discontinued use of the Saffir-Simpson scale to characterize storm surge, and is studying the possibility of issuing separate Storm Surge Warnings a few years from now. These would be in addition to their traditional Hurricane Warnings. To give us a better idea of a storm's surge potential, Dr. Mark Powell of NOAA's Hurricane Research Division has developed the Integrated Kinetic Energy scale to rank storms. The scale ranges from 0 to 6, and a parallel wind damage scale that runs from 0 to 6 is also generated. Alex had an Integrated Kinetic Energy of 2.6 on the 0 to 6 scale at 1:30pm CDT yesterday, and its destructive potential rating for winds was just 1.2. Thus, Alex's surge ranked alomst one-and-a-half categories higher in destructive potential than its wind. These numbers have probably increased by a full category since yesterday afternoon. NHC is giving a 40% - 60% chance of a storm surge of at least 3 feet affecting the Brownsville area, and 10% - 30% chance the surge will exceed 5 feet. In theory, a Category 2 hurricane moving WNW at 5 mph can bring a storm surge of up to 8 - 9 feet to the South Texas and northern Mexican coast.

Other Impacts
Alex is bringing bands of heavy rain to the coasts of Texas and Mexico, as seen on the Brownsville, Texas radar. Hurricane local statements with projections for how Alex will affect the coast are now being issued by the National Weather Service in Brownsville and Corpus Christi. Flooding damage from the expected 6 - 12 inches of rain from Alex will be the main concern. Wind damage is a lesser concern, since the core of Alex is making landfall in a swampy, sparsely populated region of Mexico. The combined wind, surge, and flooding damage from Alex may be similar to 2008's Hurricane Dolly, which hit near Brownsville. Dolly was a Category 2 hurricane offshore that weakened to a Category 1 hurricane with 85 mph winds when it made landfall, and did about $1 billion in damage. Dolly also generated two weak EF-0 tornadoes, and Alex is capable of generating a few tornadoes as well, according to the latest discussion from NOAA's Storm Prediction Center. The atmosphere is moderately unstable, there is plenty of moisture, and wind shear at low levels has been increasing this morning. The greatest threat for tornadoes will occur late this afternoon, on the right side of where the storm makes landfall.

Alex in historical context
Alex is the first June hurricane since Hurricane Allison of 1995. Allison briefly became a minimal 75 mph hurricane before weakening and hitting the Florida Panhandle as a tropical storm. Alex is the strongest June hurricane since Hurricane Bonnie of 1986, which had 85 mph winds. Bonnie was the first hurricane I flew into as a member of the Hurricane Hunters. Bonnie made landfall along the upper Texas coast, and caused less than $20 million in damage. If Alex strengthens to 90 mph winds, it will be the strongest June hurricane since Hurricane Alma of 1966, which had 125 mph winds as it skirted the Florida Keys. There have been only ten hurricanes in May or June since 1945; only four of these were major Category 3 or higher storms.

Track forecast for Alex
All of the models take Alex to the west or west-northwest into northern Mexico by early Thursday morning. However, the steering currents are fairly weak, and Alex could stall and move erratically at times today. I don't anticipate that this weakness in the steering currents will allow Alex to move northward and make landfall in Texas. After landfall, the ridge of high pressure forcing Alex westward should remain in place and strengthen, keeping Alex's remnants over northern Mexico for several days.

Intensity forecast for Alex
Alex is over a region of ocean with moderately high total ocean heat content . Wind shear has fallen to a low 5 knots, and is projected by the SHIPS model to remain in the low range, below 10 knots, through landfall. The combination of low wind shear, moderately high ocean heat content, and plenty of moisture should allow Alex to continue to intensify today. Alex's pressure is already characteristic of a Category 3 hurricane, but the storm is so large that it is taking time for the winds to catch up to the pressure falls. It is unlikely that Alex's winds will be at Category 3 strength at landfall, since the storm is undergoing an eyewall replacement cycle, and does not have time to build a tight inner eyewall with strong winds before landfall. A Category 2 storm at landfall looks more likely.

Elsewhere in the tropics
The latest run of the NOGAPS model predicts the formation of a tropical disturbance in the Western Caribbean on Monday. None of the other models is showing anything brewing over the coming seven days.

Wind and ocean current forecast for the BP oil disaster
Alex is generating very rough conditions over the Deepwater Horizon blowout location, with 6 - 8 foot waves and 3 - 4 foot swells. Strong southeast to south winds of 15 - 25 knots will blow over the oil slick region today through Thursday, according to the latest marine forecast from NOAA. The resulting currents will push oil to many protected bays and estuaries that haven't seen oil yet. In addition, the 1 - 2 foot storm surge Alex is generating along the Louisiana coast will act to push oil deep into some low-lying marshlands. While this oil will be diluted some by the wave action, the impact of the oil and accompanying toxic dispersants on the marshlands is of concern. The latest trajectory forecasts from NOAA and the State of Louisiana show oil will also move westward along the central Louisiana coast towards the Texas border. Winds will decrease to 10 - 15 knots Friday through Monday but remain out of the southeast, keeping the pressure on the regions of coast in Louisiana, Alabama, and Mississippi that are seeing oil hit their shores this week.

Resources for the BP oil disaster
Map of oil spill location from the NOAA Satellite Services Division
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

Next post
Either Rob Carver or myself will do an update late this afternoon or this evening.

Jeff Masters

Hurricane Alex (LRandyB)
Weather inbound to Hurricane Alex.
Hurricane Alex
Hurricane Alex (LRandyB)
Weather inbound to Hurricane Alex.
Hurricane Alex
Hurricane Alex (LRandyB)
Flight deck view from a WC-130J Hurricane Hunter aircraft
Hurricane Alex

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Quoting kmanislander:


Looks NNW to me now.


Yep.
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Quoting IMA:

You're much nicer than I :) Good a.m., Aqua!


I see sarcasm isn't being caught very well this morning
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Quoting Thundercloud01221991:
if this thing goes North expect major problems as South Padre Island is now shut down... no one can get out anymore the bridge is closed


Just reading that is a bit unsettling. Didn't realize they already closed that road out.
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Quoting 7544:
maybe alex sees what hitting mex can do to him and he said nope i think ill go the other way nne lol getting very interesting this am



I concur
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Official from S. Padre. Yes, the bridge is closed.
http://www.southpadretexas.gov./
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93. jpsb
Quoting hurrkat05:
kman i agree totally once that deepening trough in the sw starts to move alex n and then ne 2 states are going to scrambling..the bad part about this is they are not going to have much time alex will accelerate once the trough picks him up..a bad situation developing..
Just about everyone is saying a ridge north of alex is building, abet slowly but still building. Why do you think Alex will be able to move north or even north east?
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Member Since: July 3, 2005 Posts: 424 Comments: 128259
One thing the T-numbers and recon show us is that T-numbers aren't always the most reliable source for intensity estimates.
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F5 Time
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Quoting HurricaneSwirl:


That's the stuff that has to do with how if the mass is closer to the point of revolution it spins faster right? I had no idea what you were talking about at first lol, I was like what does an ice skater have to do with - OH
Lol. Pretty much, yeah.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting AllStar17:


I'll be honest, it looks like it is moving north according to that loop.


Looks NNW to me now.
Member Since: August 19, 2006 Posts: 0 Comments: 15816
Quoting MiamiHurricanes09:
Winds will likely not catch up because of the immense size of Alex. I would bring up the ice skater effect, but I'm sure you already know of it, lol.


That's the stuff that has to do with how if the mass is closer to the point of revolution it spins faster right? I had no idea what you were talking about at first lol, I was like what does an ice skater have to do with - OH
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Quoting StormW:


???
I'm just going with what Dr. Masters said in the blog above.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting Daveg:
Hello all.

Am I losing it, or does the center appear to be going more NW on the Brownsville radar than WNW?

Link


Ok, lets not proclaim a "Charley" is happening, wait and see if it continues. People in Brownsville should have prepared anyways.
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Thanks DRM. I almost started saying someone told me Rita was going through EWRC when she made landfall. Then I thought UGH! Not another old hurricane story! But then again the only thing that would be worse than an old hurricane story is a NEW hurricane story. Sigh. Go into Mexico and fall apart Alex.
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Quoting Daveg:
Hello all.

Am I losing it, or does the center appear to be going more NW on the Brownsville radar than WNW?

Link



Member Since: January 30, 2010 Posts: 0 Comments: 3259
80. IMA
South Padre Island Beach Cam
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Quoting kmanislander:


Yep, and can be seen here well North and East of the next forecat point.The NHC will need to do some scrambling with this as the current track forecast is busted.


Kman always like to read your thoughts, direct and to the point without the "fluff"
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Keep in mind these are flight level winds and are not at the surface. 92 knots translates to about 106mph.

000
URNT15 KNHC 301435
AF306 1101A ALEX HDOB 51 20100630
142530 2418N 09457W 8428 01380 9866 +195 +167 139068 068 057 005 00
142600 2419N 09456W 8429 01382 9870 +190 +170 139067 068 056 005 03
142630 2420N 09454W 8430 01384 9878 +183 +174 136068 070 058 010 00
142700 2421N 09453W 8426 01391 9892 +163 +163 137066 067 060 011 03
142730 2422N 09452W 8426 01393 9896 +161 +161 139077 083 060 011 00
142800 2423N 09451W 8438 01384 9905 +157 +157 135085 086 060 012 00
142830 2424N 09450W 8434 01394 9910 +157 +157 135086 087 061 009 00
142900 2425N 09448W 8429 01404 9918 +151 +151 136087 088 058 010 00
142930 2426N 09447W 8422 01416 9914 +162 +162 137087 089 057 009 00
143000 2427N 09446W 8446 01395 9916 +169 +160 140083 086 050 012 00
143030 2429N 09445W 8423 01418 9915 +171 +159 141088 090 051 006 00
143100 2430N 09444W 8422 01422 9918 +171 +159 139087 091 051 006 00
143130 2431N 09442W 8435 01410 9919 +175 +158 142088 089 052 004 00
143200 2432N 09441W 8429 01421 9922 +176 +159 142086 087 053 006 00
143230 2433N 09440W 8429 01423 9925 +175 +161 141084 085 054 006 00
143300 2434N 09439W 8428 01427 9930 +171 +164 140087 088 053 006 00
143330 2435N 09437W 8429 01429 9935 +170 +165 138090 092 052 006 00
143400 2436N 09436W 8425 01435 9937 +171 +165 137089 090 053 006 00
143430 2437N 09435W 8425 01440 9942 +170 +164 138090 091 052 007 00
143500 2438N 09434W 8432 01433 9943 +170 +164 138088 089 052 009 00
$$
;
Member Since: September 2, 2009 Posts: 130 Comments: 21193
77. 7544
maybe alex sees what hitting mex can do to him and he said nope i think ill go the other way nne lol getting very interesting this am
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Quoting txalwaysprepared:


I believe S. Padre closes the bridge at 35 mph winds.


I thought it was 45 knots (50 mph). With that rain band, I am sure there are 50 mph gusts, and the bridge is closed now.
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Hello all.

Am I losing it, or does the center appear to be going more NW on the Brownsville radar than WNW?

Link
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000
URNT15 KNHC 301435
AF306 1101A ALEX HDOB 51 20100630
142530 2418N 09457W 8428 01380 9866 +195 +167 139068 068 057 005 00
142600 2419N 09456W 8429 01382 9870 +190 +170 139067 068 056 005 03
142630 2420N 09454W 8430 01384 9878 +183 +174 136068 070 058 010 00
142700 2421N 09453W 8426 01391 9892 +163 +163 137066 067 060 011 03
142730 2422N 09452W 8426 01393 9896 +161 +161 139077 083 060 011 00
142800 2423N 09451W 8438 01384 9905 +157 +157 135085 086 060 012 00
142830 2424N 09450W 8434 01394 9910 +157 +157 135086 087 061 009 00
142900 2425N 09448W 8429 01404 9918 +151 +151 136087 088 058 010 00
142930 2426N 09447W 8422 01416 9914 +162 +162 137087 089 057 009 00
143000 2427N 09446W 8446 01395 9916 +169 +160 140083 086 050 012 00
143030 2429N 09445W 8423 01418 9915 +171 +159 141088 090 051 006 00
143100 2430N 09444W 8422 01422 9918 +171 +159 139087 091 051 006 00
143130 2431N 09442W 8435 01410 9919 +175 +158 142088 089 052 004 00
143200 2432N 09441W 8429 01421 9922 +176 +159 142086 087 053 006 00
143230 2433N 09440W 8429 01423 9925 +175 +161 141084 085 054 006 00
143300 2434N 09439W 8428 01427 9930 +171 +164 140087 088 053 006 00
143330 2435N 09437W 8429 01429 9935 +170 +165 138090 092 052 006 00
143400 2436N 09436W 8425 01435 9937 +171 +165 137089 090 053 006 00
143430 2437N 09435W 8425 01440 9942 +170 +164 138090 091 052 007 00
143500 2438N 09434W 8432 01433 9943 +170 +164 138088 089 052 009 00
$$
;
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Quoting angiest:


I think bridges to barrier islands, as well as ferry's, shut down around the time of tropical storm force winds.


I believe S. Padre closes the bridge at 35 mph winds.
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Quoting HurricaneSwirl:


Maybe winds are finally starting to catch up? And at a fairly rapid rate too. Before I left for the dentist all they could find were 60-70 mmph winds on the surface.
Winds will likely not catch up because of the immense size of Alex. I would bring up the ice skater effect, but I'm sure you already know of it, lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting MiamiHurricanes09:
Strongest flight level winds reported by recon were 89 knots, which is about 102mph. Pretty impressive if ya ask me.


That's a cat. 2! NHC was predicting a possible 25+ kt strengthening in 24 hours before landfall from the 4am advisory. So far it looks like it has strengthened perhaps 8-10 kt in 6 hours.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
The bridge ramps are getting close to going underwater, probably why they have closed it. Water has been coming up fairly quickly this morning.

Bridge Cam
Edit:
Closure not verified by me, just commenting
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Quoting kmanislander:


Yep, and can be seen here well North and East of the next forecat point.The NHC will need to do some scrambling with this as the current track forecast is busted.


I'll be honest, it looks like it is moving north according to that loop.
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NW for sure Folks

Member Since: January 30, 2010 Posts: 0 Comments: 3259
Quoting angiest:


I think bridges to barrier islands, as well as ferry's, shut down around the time of tropical storm force winds.


Be careful with disseminating info like this that has not been confimed or actually declared by local emergency management authorties in the official warned areas. Lots of folks, at these critical times, look on the Blog for general information but you don't want to be assuming facts when folks are making potential life/death decisions........They need to contact their local emergency management folks/local media outlets on this kind of critical information.
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WOW!! Has anybody seen this yet??

30/1145 UTC 23.6N 95.3W T5.5/5.5 ALEX -- Atlantic

That T number is the line for major hurricane status. (although it is just Dvorak, but it still impresses me)
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92 knt flight level winds!!!
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latest vortex message suggests a minimum central pressure of 961mb. Looks like Alex is going through an eyewall replacement cycle. Also a 102mph flight level wind was reported, quite impressive.

000
URNT12 KNHC 301432
VORTEX DATA MESSAGE AL012010
A. 30/14:05:40Z
B. 23 deg 49 min N
095 deg 26 min W
C. 850 mb 1063 m
D. 54 kt
E. 300 deg 10 nm
F. 052 deg 62 kt
G. 304 deg 15 nm
H. 961 mb
I. 20 C / 1522 m
J. 24 C / 1523 m
K. 20 C / NA
L. NA
M. NA
N. 12345 / 8
O. 0.02 / 1 nm
P. AF306 1101A ALEX OB 20
MAX FL WIND 89 KT NE QUAD 14:19:10Z
MAX OUTBOUND FL WIND 89 KT NE QUAD 14:19:10Z
MAX OUTBOUND AND FL WIND 89 KT NE QUAD 14:19:10Z
;

Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting Skyepony:

B. Center Fix Location: 195 miles (313 km) to the SE (139°) from Brownsville, TX, USA.


Wow that's close to my hand fix on the radar. I am at about 165nm at 137 degrees.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting AllStar17:




Yep, and can be seen here well North and East of the next forecat point.The NHC will need to do some scrambling with this as the current track forecast is busted.
Member Since: August 19, 2006 Posts: 0 Comments: 15816
Quoting MiamiHurricanes09:
Strongest flight level winds reported by recon were 89 knots, which is about 102mph. Pretty impressive if ya ask me.


Maybe winds are finally starting to catch up? And at a fairly rapid rate too. Before I left for the dentist all they could find were 60-70 mmph winds on the surface.
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55. 7544
Quoting FLdewey:


LMAO... YES!!! For the win!!!

Tampa should start putting up the shutters. ;)


oooooo h are they going to reverse to cone lol
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Quoting MiamiHurricanes09:
Strongest flight level winds reported by recon were 89 knots, which is about 102mph. Pretty impressive if ya ask me.


I wonder how long it will be till we transfer that to the surface???
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By the way, Thanks for the update Dr. Masters!
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Quoting AllStar17:
Nearly 100 mph flight level winds reported by recon now. I'd think it will be 90 mph at 11 am.


Strongest flight level winds reported by recon were 89 knots, which is about 102mph. Pretty impressive if ya ask me.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting doabarrelroll:


I have a NOOB question. if there is no thunderstorm activity outside of the eyewall does that mean there is no wind there? Or is it just showing a lack of rain


I believe what you are seeing is the radar being unable to penetrate the heavier rain in some of the bands. Plus, a lot of what you are seeing is still way out and you are looking higher into the circulation the further out you get.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting Orcasystems:


120 miles... 5 hours...


Wow, that's actually 24 mph.

Anyway, I wasn't disagreeing, just saying that it really doesn't look like it on satellite. The actual data is always better though.
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How fitting that the abbreviation for the storm surge rankings would be IKE ;)
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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.