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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Member Since: June 9, 2007 Posts: 4 Comments: 15921
2147. Levi32
Look at the outflow....you almost can't get more perfect than that....the streamlines going perpendicular OUT from the eye in every direction. Center of ZERO shear is over the eye. That is as symmetrical of an upper high as you could want.

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Looks like the band with those TS Force winds have slipped South of Brownsville as Alex decided to make alittle dip South.
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Quoting Stormchaser2007:


Honestly, I have seen some Cat 4 storms not as impressive as Alex.

This is not a Cat 1.




Impressive imagery and destructive force are two different measures, technically. The Saffir-Simpson scale measures the latter.
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Quoting sarahjola:
don't all storms slow down when they approach land?:)


Alex is a large storm, so the moutains of Mexico are probably causing the storm to squeeze and slow down.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
2142. Patrap
Quoting c150flyer:
I'm not a station, just a guy with an anemometer looking like an idiot on the side of the freeway, but i can confirm what you just said... nowhere near TS strength sustained here............yet?? =)

BTW - Thanks patrap for the quick info. I'm getting some good sustained winds in the neighborhood of 25mph, the gusts are just being kind of puny.

Good for Brownsville. Bad for my adrenaline lol.


I know da feeling, Be safe.

Seems the Storm may be slowing some nearing landfall in forward motion.
Member Since: July 3, 2005 Posts: 426 Comments: 128866
Quoting weatherguy03:
Turn the camera!..LMAO


Bob, so good to see you here again!!!!
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2140. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 128866
Hurricane Dolly was only a Cat 1 at landfall.

Member Since: June 9, 2007 Posts: 4 Comments: 15921
I'm not a station, just a guy with an anemometer looking like an idiot on the side of the freeway, but i can confirm what you just said... nowhere near TS strength sustained here............yet?? =)

BTW - Thanks patrap for the quick info. I'm getting some good sustained winds in the neighborhood of 25mph, the gusts are just being kind of puny.

Good for Brownsville. Bad for my adrenaline lol.
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Quoting 1900hurricane:

Don't worry, I posted an image on his blog so he won't completely miss out. :)


That was a nice thing to so, thank you!
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2136. Levi32
You don't get Cat 1 hurricanes with 955mb pressure....it simply does not happen. I can accept this being a solid Category 2, but it has the pressure and appearance of a major hurricane.
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i see a upgrande comeing at post season
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Quoting Patrap:


Seems to some for sure.

And another Sw dip.

"When u dip,I dip,we dip"


Just don't you dare put your hand on my hip Mr.!
Member Since: September 6, 2009 Posts: 2 Comments: 3767
This puts it into perspective...

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Quoting Tazmanian:



07 what do you think


it looks like this storm is makeing land fall at the same spot has this storm did



Yes, but compare the radars:



At the time, Emily was a 125 mph cat. 3. And yes, that IS the entire hurricane.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Quoting houstongator:
While we are having fun with OZ today - I'll bet sometime this season he gets some really good video and has a ton of viewers, I just hope he survives it.


Honestly, he needs to get in shape before he tackles a real Cane. And learn how to use the camera properly. But maybe this is just the practice run.
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Quoting Levi32:


That's not a June storm.
Quoting Stormchaser2007:


Honestly, I have seen some Cat 4 storms not as impressive as Alex.

This is not a Cat 1.

This is just unreal, but there it is, real as can be!
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Quoting Patrap:


Sure you should..a Inbound feeder shows some 50Plus Gust with some sustained @ 25 a coming round.

NEXRAD Radar
Brownsville, Storm Relative Mean Radial Velocity 1.45 Degree Elevation Range 124 NMI



Hi to everyone! How can one determine where can possibly a tornado occur or a mesocyclone based on Storm Relative Mean Radial Velocity ?
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Quoting FLdewey:
No someone needs to take his copy of Twister away. I bet he dropped some grass to the ground this morning, looked to the sky and said "going green"

I hope he's not trying to pass himself of as a storm chaser to the media.


ur rude.
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Looks like last eye punch by the hurricane hunters on Alex?
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2126. barbamz
Quoting Grothar:


I know. Hard to believe it is still June and tomorrow being my birthday. July 1, MY BIRTHDAY. Don't see those Hurricane that strong this early too often.

In Germany it's already tomorrow. Happy birthday, Grothar!
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2125. Patrap

727
WGUS54 KBRO 302230
FFWBRO
TXC061-215-010030-
/O.NEW.KBRO.FF.W.0021.100630T2230Z-100701T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BROWNSVILLE TX
530 PM CDT WED JUN 30 2010

THE NATIONAL WEATHER SERVICE IN BROWNSVILLE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
HIDALGO COUNTY IN DEEP SOUTH TEXAS.
SOUTHWESTERN CAMERON COUNTY IN DEEP SOUTH TEXAS.

LOCATIONS AFFECTED INCLUDE...
LA FERIA.
LOS EBANOS.
LINN.
HIDALGO.
SAN MANUEL.
MCCOOK.
WESLACO.
SAN JUAN.
PHARR.
MISSION.
MERCEDES.
MCALLEN.
EDINBURG.
EDCOUCH.
DONNA.
ALAMO.

* UNTIL 730 PM CDT

* AT 522 PM CDT...SCATTERED AREAS OF FLOODING HAVE BEEN REPORTED
WITH RAINFALL AMOUNTS OF 3 TO 6 INCHES HAVING OCCURRED ACROSS THE
WARNED AREA TODAY. ADDITIONAL RAINFALL IS EXPECTED THIS EVENING WITH
AN ADDITIONAL 1 TO 3 INCHES OF RAIN POSSIBLE AS RAIN BANDS
ASSOCIATED WITH HURRICANE ALEX CONTINUE TO AFFECT THE AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE ROAD.
THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS SAFELY.
MOVE TO HIGHER GROUND.

DON'T BECOME A STATISTIC. TURN AROUND...DON'T DROWN!
Member Since: July 3, 2005 Posts: 426 Comments: 128866
Quoting Tazmanian:
i want my cat 5
Rancho la piedra, La pesca, Alex'x target towns, wouldn't like those words I'm sure.
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2123. Levi32
Brownsville and most of south Texas is getting spared the worst of the storm. Most stations aren't even getting tropical storm force winds right now.
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Quoting Tazmanian:



07 what do you think


it looks like this storm is makeing land fall at the same spot has this storm did


Well, I'm not 07, but I looks like a similar spot to me.
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Quoting Levi32:


That's not a June storm.


Honestly, I have seen some Cat 4 storms not as impressive as Alex.

This is not a Cat 1.


Member Since: June 9, 2007 Posts: 4 Comments: 15921
2119. Patrap
Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 30th day of the month at 22:28Z
Date: June 30, 2010
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 304)
Storm Number: 01
Storm Name: Alex (flight in the North Atlantic basin)
Mission Number: 12
Observation Number: 48



22:28:00Z 24.183N 96.900W 843.5 mb

(~ 24.91 inHg) 1,273 meters

(~ 4,177 feet) 974.5 mb

(~ 28.78 inHg) - From 218° at 62 knots

(From the SW at ~ 71.3 mph)
Member Since: July 3, 2005 Posts: 426 Comments: 128866
Quoting Patrap:


By that radar, it looks like wobbling Alex might not make landfall until about midnight. (By "landfall", I mean on the inner coast, not on a barrier island.)
Member Since: August 30, 2008 Posts: 8 Comments: 2835
2117. leo305
Quoting sarahjola:
don't all storms slow down when they approach land?:)


nope
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2116. Grothar
Quoting hydrus:
I am doing good Grothar. It looks like August in the Gulf of Mexico for some reason....


I know. Hard to believe it is still June and tomorrow being my birthday. July 1, MY BIRTHDAY. Don't see those Hurricane that strong this early too often.
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While we are having fun with OZ today - I'll bet sometime this season he gets some really good video and has a ton of viewers, I just hope he survives it.
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Quoting Stormchaser2007:
Extremely impressive




07 what do you think


it looks like this storm is makeing land fall at the same spot has this storm did

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2113. Levi32
Quoting Stormchaser2007:
Extremely impressive



That's not a June storm.
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2112. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 128866
Good job Pat you completed your dot to dot windmill! Now see if you can do the cow or barn.
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don't all storms slow down when they approach land?:)
Member Since: September 10, 2008 Posts: 0 Comments: 1294
Extremely impressive

Member Since: June 9, 2007 Posts: 4 Comments: 15921
2108. leo305
alex likes to play around..

first it was stationary over the southern gulf, then it decided to speed up towards land, and now it decides to slow down before landfall..
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2107. Patrap
Quoting c150flyer:
While not as exciting as Oz under a powerline in MX, here two miles north of downtown Brownsville, we just had our first TS strength GUST... a whopping 39.4mph.

Any of the experts on here willing to chime in as to whether I can expect stronger winds this far "inland"?


Sure you should..a Inbound feeder shows some 50Plus Gust with some sustained @ 25 a coming round.

NEXRAD Radar
Brownsville, Storm Relative Mean Radial Velocity 1.45 Degree Elevation Range 124 NMI

Member Since: July 3, 2005 Posts: 426 Comments: 128866
2105. scott39
Quoting Patrap:


Seems to some for sure.

And another Sw dip.

"When u dip,I dip,we dip"
You go old school! LOL
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Wow Alex slowed a bunch.
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it looks like Alex is makeing land fall at the same spot where this storm did

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2102. Levi32
Good afternoon/evening, checking in for lunch break. Alex appears to have continued strengthening. This is a very very solid Category 2, not a Cat 1. Track also appears to have resumed west movement and now WSW back towards the original forecasted landfall points well south of the border. I've about had it with him toying with us regarding the steering currents lol.
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2101. Patrap
Quoting leo305:
slowed down a bit on radar


Seems to some for sure.

And another Sw dip.

"When u dip,I dip,we dip"
Member Since: July 3, 2005 Posts: 426 Comments: 128866
While not as exciting as Oz under a powerline in MX, here two miles north of downtown Brownsville, we just had our first TS strength GUST... a whopping 39.4mph.

Any of the experts on here willing to chime in as to whether I can expect stronger winds this far "inland"?
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Turn the camera!..LMAO
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2098. hydrus
Quoting FLdewey:


That's what the baseball cleats are for... insulation. ;)
And a little traction for those wicked gusts.:)
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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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