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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He's beautiful.
Member Since: May 17, 2007 Posts: 0 Comments: 632
1947. JamesSA
Quoting SLU:


AMAZING! In all my years of weather watching i've never seen a June hurricane looking like this.
I've been to that spot on the barrier island where it is about to make landfall. There is nothing whatsoever there. Just beach with miles of swampy wetlands behind it. Great fishing!

The little town of San Fernando a little ways inland is very small, and I recall most of the buildings were made of concrete and/or concrete blocks. That is typical construction even for little houses in Mexico, they don't use much lumber. They should be OK, they are rugged people who have been through these before.
Member Since: August 17, 2009 Posts: 0 Comments: 579
Alex is a pretty little hurricane!
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Oz is about to be interviewed!
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Didnt take the season long to show its colours.
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Quoting Tazmanian:
isnt 100kt a cat 3


Yeah it's 115.07 mph
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Quoting Tazmanian:
isnt 100kt a cat 3

Correct.
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Alex approaching the coast with available Doppler radar is a sombering sight that will probably be repeated a few times in the Caribbean this year without the benefit of Doppler images....I don't want to imagine having to repeat watching this type of Doppler approach on a US coatline later this year; hard to beleive this "view" is occuring June but here we are.
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isnt 100kt a cat 3
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1939. Makoto1
I'm not great with hurricanes like a lot here but I'm here lurking and staring at it in awe. Good luck to all of you in Mexico in Texas in this storm, and looking forward to track all this year.

I'll still mostly lurk because I don't typically have much to share, just figured I'd wish people the best.
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oz www.7674u.com
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1937. NRAamy
Quoting russm1:
Poor OZ, dude lose some weight and trash the cigs you're puffing like an 80 year old man..lol



aw, man, that's not nice!

;)
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Quoting TexasGulf:


Despite Alex being a borderline Cat 1/2 hurricane... even being in the eyewall wouldn't be all that impressive. The winds speed and turbulence are good, but not heart-attack good.

I would think that if you ever wanted to swim in your pool or hot-tub during a hurricane eyewall... Alex would be tame enough to try it. It would be an experience if you don't mind your beer mixed with tropical rain.


I actually lived through Hurricane David that hit Savannah in 1979...was at the airport in Savannah when the eye came through, and when it was over us, I was able to go outside and walk our dog. It was pretty peaceful, hardly any wind and the sun actually shined...didn't last very long and when the eye passed the winds came from the opposite direction...all the trees that had been bent one way for so long, snapped when the wind direction changed.
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NHC will likely make Alex a Category 2 by 8 pm, right before landfall.
Member Since: July 8, 2005 Posts: 259 Comments: 24580
Just hit 360 mark.
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i no am being a Doomcaster but any way in heck this storm will stall out a little or slow down so we can brak some good records?
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Quoting leo305:
I said it was developing a very small pin hole like eye, and someone attacked me for it.. Now I demand an apology!

lol jk

Interesting developments right now.. it's almost completely clear on visible, and pressure continues to drop quickly
I did yesterday, and NO I will not apologize because at that time it was JUST an EYE.
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Quoting HurricaneSwirl:
I think 2010's got 2005 beat for June.. doubt it will remain that way for July.


For earliest hurricane of the two.
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1929. GBguy88
Quoting Patrap:


What a Premiere for 2010, eh?





It's certainly a damn good looking eye and eyewall for being a 'Cat 1'.
Member Since: August 22, 2008 Posts: 0 Comments: 488
Quoting FLdewey:


LMAO... 334 whole people?

To be honest never. I have never broadcast myself on the web, and I'm okay with that. I was a volunteer firefighter for a number of years, so maybe that satisfied my need for attention. ;)



I assume they are all whole, but what do I know?

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I think 2010's got 2005 beat for June.. doubt it will remain that way for July.
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Quoting Bordonaro:

It is beautiful, amazing and thankfully moving into a sparsely populated area in Mexico


Well it's not Houston metro, but San Fernando "metro" in Mexico has over 200,000 people. 35 miles inland from anticipated landfall. I don't consider that sparsely populated.
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Quoting GBguy88:


But he's out there with the spirit of a child ;)
anyone have the link to Oz's Site?
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Quoting doabarrelroll:

its weakass over hyped storms like this that make people believe hurricanes are no big deal


Wow really?

weak storm? hardly
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1921. leo305
Quoting TankHead93:
Shame! if only it had more time over the gulf... we could have broken a record.


it still can.. it has 2-3 hours left
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1920. Patrap
Quoting 1900hurricane:

Moat's filling up. Alex sure is pulling out all the stops now! He's just running out of time though.


What a Premiere for 2010, eh?



Member Since: July 3, 2005 Posts: 428 Comments: 129904
1919. JamesSA
Quoting GBguy88:


But he's out there with the spirit of a child ;)
A child of what age is the question. ;-)
Member Since: August 17, 2009 Posts: 0 Comments: 579
Shame! if only it had more time over the gulf... we could have broken a record.
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From GOES-15:

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1915. leo305
I said it was developing a very small pin hole like eye, and someone attacked me for it.. Now I demand an apology!

lol jk

Interesting developments right now.. it's almost completely clear on visible, and pressure continues to drop quickly
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1913. GBguy88
Quoting russm1:
Poor OZ, dude lose some weight and trash the cigs you're puffing like an 80 year old man..lol


But he's out there with the spirit of a child ;)
Member Since: August 22, 2008 Posts: 0 Comments: 488
Quoting Stormchaser2007:
First pinhole eye Ive seen in a while.




and dran too bad this thing dont have more time or we would have had a strong cat 4 or 5 land fall and yes am sorry for being a wishcaster but its ture
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FLdewey oh my god that made me laugh out loud!
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Quoting Thundercloud01221991:
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 30 JUN 2010 Time : 204500 UTC
Lat : 24:26:39 N Lon : 96:55:13 W


CI# /Pressure/ Vmax
4.8 / 973.5mb/ 84.8kt


Final T# Adj T# Raw T#
4.8 6.0 6.0


Latitude bias adjustment to MSLP : -0.1mb

Estimated radius of max. wind based on IR :N/A km

Center Temp : -42.1C Cloud Region Temp : -71.1C

Scene Type : EYE

Positioning Method : SPIRAL ANALYSIS

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF



Incredibly impressive satellite presentation in the last 2-3 hours. No question we'll have a Category 2 storm by the intermediate advisory.
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Quoting Patrap:

Moat's filling up. Alex sure is pulling out all the stops now! He's just running out of time though.
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1906. SLU


AMAZING! In all my years of weather watching i've never seen a June hurricane looking like this.
Member Since: Posts: Comments:
Quoting Thundercloud01221991:
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 30 JUN 2010 Time : 204500 UTC
Lat : 24:26:39 N Lon : 96:55:13 W


CI# /Pressure/ Vmax
4.8 / 973.5mb/ 84.8kt


Final T# Adj T# Raw T#
4.8 6.0 6.0


Latitude bias adjustment to MSLP : -0.1mb

Estimated radius of max. wind based on IR :N/A km

Center Temp : -42.1C Cloud Region Temp : -71.1C

Scene Type : EYE

Positioning Method : SPIRAL ANALYSIS

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF


I wonder if NHC will upgrade it to a Cat 2.
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Quoting IKE:
I'd hate to be in that eye. I'd probably die of a heart attack. A June beast.


Despite Alex being a borderline Cat 1/2 hurricane... even being in the eyewall wouldn't be all that impressive. The winds speed and turbulence are good, but not heart-attack good.

I would think that if you ever wanted to swim in your pool or hot-tub during a hurricane eyewall... Alex would be tame enough to try it. It would be an experience if you don't mind your beer mixed with tropical rain.
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No offense to all or any of you, but I deal in ebay sometimes...This approaching storm reminds me of the last few minutes of an online EBAY auction when everyone is trying to get in the last bid, "Or the last word" before it is over.Just a thought.
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1901. russm1
Poor OZ, dude lose some weight and trash the cigs you're puffing like an 80 year old man..lol
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1898. leo305
NHC-

"Will be a CAT 2, may approach CAT 3 intensity, but thankfully its going to make landfall in 3 hours"
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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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