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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1048. Patrap
Wait for.it, Ez,

..wait for it..

LOL
Member Since: July 3, 2005 Posts: 423 Comments: 127847
Quoting MiamiHurricanes09:
NOGAPS shows the same thing but takes it to Florida.



NOGAPS = dreamcaster
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we here in SELA are gettn some heavy rain. winds have picked up too. we are under a flood watch till thur due to tropical moisture from Alex and a trough over us. Good luck to those in the storms path!
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1045. IKE
Quoting CybrTeddy:
ECMWF develops a low in the SW Caribbean too. ECMWF was the model that caught Alex's development well in advance.



NOGAPS also was with the ECMWF in Alex's formation.

Looks like the disturbance takes a similar track to Alex too.


That's yesterdays 12Z ECMWF...today's at 240 hours would be July 10th, 2010.
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Quoting 1900hurricane:

This is the third day in a row it has done so.


Identical as a matter of fact to the consistency it showed for Alex. ECMWF caught Alex well in advance.
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Quoting ShenValleyFlyFish:


He should be. I'll do the paperwork.

Other thing he tried and succeeded at was hijacking this blog to promote his foolishness.


I woudl have to assume that he was permanently banned for just that reason, at least in large part
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Quoting IKE:
1:00 PM CDT Wed Jun 30
Location: 24.4N 96.2W
Max sustained: 85 mph
Moving: NW at 12 mph
Min pressure: 962 mb


Is Alex's central pressure rising?

Quoting muddertracker:
Good afternoon everyone. Did I wake up in August?


I was talking earlier about how the SST patterns looked more like August or September than June or July.

Quoting extreme236:
The NOGAPS has been rather persistent on forming this SW Caribbean system.


It usually does that all season long.
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get on land Alex, keep going!

Oz's live feed is jacked up keeps breaking up every 2 seconds, getting ready to just shut it down
Member Since: July 14, 2008 Posts: 1 Comments: 9628
1039. Patrap
Alex has closed of the Eyewall again as it runs wnw at round 295 to 300 true
Member Since: July 3, 2005 Posts: 423 Comments: 127847
Quoting Asta:
971- yep spawning tornados...
Hunker-down Texas and hold on!!


i agree, i don't see alex going to mexico.

he is still going north!
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Quoting angiest:


I live on the west side of Houston, so we did get that message. :) For Rita in the inland hurricane wind warnings went several counties back from the coast. Can't remember how far for Ike but Dallas was in a TS wind watch, which is amazing at ~300 miles from the coast!


Yeah I know that Tx was warned. But even in Orange County we used to not get the same warnings as coastal counties. Rita killed people in Angelina County well over 100 miles inland. It was awful.Caused a surge on Lake Livingston and destroyed over 2 miles of the dam. Although she never was close to there. And that was her "good" side. I figured we were in trouble when they started evacuating the county we used to evacuate to.
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What in the world???....1pm advisory.

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1034. JRRP
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alex is still going north
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1032. Asta
971- yep spawning tornados...
Hunker-down Texas and hold on!!
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Tropical storm force winds on South Padre Island now. 12:55 PM CDT winds north at 41, gusting to 54 mph.
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Looks to me like Alex is going to make landfall about 7pm CDT tonight about 50 miles south of Brownsville.
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1029. JamesSA
Quoting guygee:
Little doubt that the Mexican government much more efficient at warning the populace than in earlier times, but then again it is difficult to reach so many people. The population of Monterrey in 1950 was around 300,000, and in 1909 it must of been much smaller.
Although the center of the city is basically a flash-flood zone, there is plenty of high ground nearby according to the topo maps, so it is just a matter of getting the word spread in time, without causing needless panic. That is always a high-wire balancing act that even the NHC must walk.
I was there over 20 years ago and there were many poor people living in makeshift shacks in the bottom of that dry arroyo for miles driving out of the city. When Gilbert came in and spent itself in that area of the Sierra Madres there were many deaths among those living in the dry wash. Most had been unaware anything was even coming.
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Quoting CybrTeddy:
ECMWF develops a low in the SW Caribbean too. ECMWF was the model that caught Alex's development well in advance.



NOGAPS also was with the ECMWF in Alex's formation.

This is the third day in a row it has done so.
Member Since: August 2, 2006 Posts: 46 Comments: 11666
Quoting Patrap:
But Hey,

..how bout dat radar Huh?





The eye on radar has closed.
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1026. Patrap
Member Since: July 3, 2005 Posts: 423 Comments: 127847
Quoting cctxshirl:
So, is Alex really moving a little northerly? Right now, when you look at the satellite, it looks like Alex will visit Brownsville or am I being deceived?


The last 4 HH center fixes show NW direction, but ERC may be having an effect on course at this time. NW puts it ashore just south the Rio Grand. But we all know how storms like to meander a bit as they approach land. The next center fix is going to give some important clues.
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ECMWF develops a low in the SW Caribbean too. ECMWF was the model that caught Alex's development well in advance.



NOGAPS also was with the ECMWF in Alex's formation.

Looks like the disturbance takes a similar track to Alex too.
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Member Since: June 9, 2007 Posts: 4 Comments: 15881
Member Since: August 2, 2006 Posts: 46 Comments: 11666
1020. Levi32
Blog updated.

Tropical Tidbit for Wednesday, June 30th, with Video
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I cant believe that ppl are actually trying to get a date on here....... Email ur interest in dating..... This is a weather related site not E-Harmony........



Well I got to go..... Either way, Brownsville is in for some nasty weather tonight, maybe more than they expect, lets hope not. Im still thinking close to cat 3 at landfall even with this influction of dry air at the moment. Good luck to everyone there.........
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Quoting miamiamiga:


It is items like this that would be really helpful to those of us who have space issues and can't store jugs of water for 6 months...is there anyway WU or someone who maintains a blog could put together useful information like this with links to retailers that carry them for people?


Yo got mail.
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1017. Asta
Quoting connie1976:
...Patrap, that video was unbelievable!!! when they say evacuate....they should require everyone to watch this video!!

Yep- but some people will still stay.

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1014. JRRP
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Quoting CaneWarning:


He's showing that hurricanes can be a ton of fun, isn't he?


They can be...and the sarcasm flag is off, by the way...

My problem with OZ is his intention to be there at landfall for a CAT5 if he can...
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Alex does seem to be moving more westerly from what I can tell.
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Night all,,, catch ya's soon.
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texas be prepared, alex might play a trick
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1007. Patrap
But Hey,

..how bout dat radar Huh?



Member Since: July 3, 2005 Posts: 423 Comments: 127847
Quoting reedzone:
Take a look at the NHC track, do to the northern position of Alex, kinda funny looking.


As far as 12 hour forecasts go, I think this one is pretty busted. Completely wrong on initial motion.
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Quoting extreme236:
The NOGAPS has been rather persistent on forming this SW Caribbean system.


hello, bonnie
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999: And so did you. Don't you guys have a quote filter?
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Moving more west...12Z ECMWF takes it due west from here. I expect a surge of 5-7 feet into S. Padre...we will see.
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alex is nor going to hit mexico
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1001. amd
Quoting Drakoen:


Was thinking the same thing. The vortex message showed SFMR wind around 73 knots though


yeah, I saw that. What is considered more "accurate" for surface winds, SFMR, or dropsonde measurements?
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The NOGAPS has been rather persistent on forming this SW Caribbean system.
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Quoting DrakoenG:

:)

Well by any chance, do you consider dating, at least cybredating, a possbily younger (i dont know how old you are) Mexican guy from South florida?


Not to be rude, but we have a life threatening situation going on.. Could you please move this convo to a PM? Peoples lives are at stake, especially with the change in direction of Hurricane Alex.
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Would you look at that, alex sure does have a long tail!

http://www.ssd.noaa.gov/goes/east/eaus/rb-l.jpg
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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.