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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Ive been gone for a while so I dont know
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1697. Dakster
Floodman is going to be busy soon in brownsville, Tx (Unfortunately)

Welop, chalk one up for the forecaster at NHC, they have been calling this for days and there forecast, IMHO, was good. (As were others on this blog)
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Quoting StSimonsIslandGAGuy:
I'm not so sure about that. However, I can't imagine that congress would allow people to fall through the crack---I'm sure they will put in a provision for retroactive renewals.


Lowly car salesman here. I know for a fact that we cannot write new insurance for vehicles if there is any storm in the gulf. Just 2 cents worth of input
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Quoting PensacolaDoug:
Oz is back up!


Did he close the car door?
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and pressure down to 959 mlbs
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Quoting Baltimorebirds:
A closed eye means a more intense system.


oh dear. on the radar it looks like it is getting really slammed with rain there at the border? anyway. man I bet it is making that whiney noise by now.
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1692. IKE
Quoting asgolfr999:


How about one...two max


It could be near/at the coast with the eye in 2...unless it changes course.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Oz is back up!
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Quoting Prolefeed:
i prefer my b.s. to be adulterated, myself


Now THAT's funny! Off topic, but funny. A+
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alex is officially due west at 13mph
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you'd think a lawyer wouldn't say something so definitive with no facts to back it up.

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Quoting IKE:


Unless it turns WSW. Looks like it may be moving due west OR just slightly south of west.

I agree with you...no way it's over water 6 more hours.


How about one...two max
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1684. SamTeam
Quoting NOLALawyer:


This is complete, unadulterated BS. The program is 100% in existence.


Not so my friend, nothing new & no renewals. It's holding up real estate closings all over the country, not to mention people in flood zones during 'Cane season
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you sure about that NOLA? might want to check your facts on that.

http://www.insurancejournal.com/news/national/2010/06/30/111206.htm
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Quoting StormSurgeon:


weee oooo weeee ooooo, run Flood, the blog police are coming for you.....LOL.....and me too for this wortless post....


I got your back if you have mine
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Looking at current motion direction and speed Alex will likely be making landfall tonight, around 9 PM EDT. At the moment I think that Alex will become a category 2 hurricane just prior to landfall at 8 PM EDT. I'll be back in a bit.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
1680. Titoxd
Quoting doabarrelroll:


the waters off the coast of Florida are way warmer and it was august. IMO


Per the disco:

SATELLITE IMAGES AND DATA FROM THE HURRICANE HUNTER AIRCRAFT
INDICATE THAT ALEX IS BETTER ORGANIZED...AND THAT THE
WINDS HAVE INCREASED. THE MAXIMUM FLIGHT LEVEL WINDS REPORTED SO FAR
ARE 96 KNOTS AND SFMR REPORTED 81 KNOTS TO THE NORTHWEST OF THE
CENTER. IN ADDITION...THE EYE HAS BECOME DISTINCT ON VISIBLE IMAGES
AND IS SURROUNDED BY A CIRCULAR AREA OF DEEP CONVECTION. BASED ON
THESE DATA...THE INITIAL INTENSITY HAS BEEN INCREASED TO 80 KNOTS.
ENVIRONMENTAL CONDITIONS COULD ALLOW ALEX TO BECOME A CATEGORY TWO
HURRICANE BEFORE LANDFALL.
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measuring due west, Alex is 53 miles from the coastline, so at 13mph he would make landfall in 4 hours
Member Since: March 10, 2010 Posts: 1 Comments: 7677
1678. IKE
Quoting seflagamma:


Ike, that is crazy, it will be on land by 10pm CDT won't it?

wish they would give more frequent updates this close to landfall.

Hi everyone...lurking but not posting much..



They're updating every 2 hours now. I think landfall will happen in 2-4 hours.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Remember, the strongest winds are in the eye wall in the front right quadrant (northwest in this case). Once out of the eye wall, wind speeds will drop sharply with distance. Brownsville will have to deal with flooding problems but winds will be a minimal factor.
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Quoting BobinTampa:
Hope nobody in Texas has a flood insurance policy that came up for renewal this month. Congress still hasn't re-authorized the program.

Those whose policies expired in June are now in limbo.



This is complete, unadulterated BS. The program is 100% in existence.
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Forecast Inundation Surge a little higher








Link
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1673. IKE
Quoting RavensFan:
no way alex has another 6 hours over water


Unless it turns WSW. Looks like it may be moving due west OR just slightly south of west.

I agree with you...no way it's over water 6 more hours.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Now looking like 5 hours to landfall based on distance, speed and heading from last 2 HH center fixes. 1:15Z July 1st ... 9:15 Eastern tonight. That's the XTRP :-)
Member Since: July 15, 2005 Posts: 3 Comments: 1266
Floodman, you behaving this afternoon?
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Quoting IKE:
NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORIES...600 PM CDT AND 800 PM CDT.
NEXT COMPLETE ADVISORY...1000 PM CDT.


6 p.m.? Oh wait.. they do this with landfalling storms, nevermind :P
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Quoting WaterWitch11:
The boy's name Alexander. It is of Greek origin, and its meaning is "man's defender, warrior". From the Latin form of the Greek name Alexandros. The name was probably coined originally as a title of the goddess Hera, consort of Zeus

afternoon flood!


Good afternnon, my well-educated friend! You're rather impressive, you know that?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting IKE:
NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORIES...600 PM CDT AND 800 PM CDT.
NEXT COMPLETE ADVISORY...1000 PM CDT.


Ike, that is crazy, it will be on land by 10pm CDT won't it?

wish they would give more frequent updates this close to landfall.

Hi everyone...lurking but not posting much..
until now! LOL

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no way alex has another 6 hours over water
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Quoting Floodman:


OMG...stop it, you're killing me!

THE MIC
4pm with windfield

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Quoting KORBIN:
Since we know what's going on with Alex,

What is our 4th of July going to look like for the rest of the Gulf Coast?

Any Spurious Lows? Blobs? Invests? Aoi?


[Nogaps] shows what appear to be waves of tropical systems moving towards U.S.

I'm not sure it's going to be a good year, except here.
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Looks like Brownsville as I thought earlier, will be spared of Hurricane Force winds, though any shift of the track can change the whole forecast.
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Quoting twhcracker:


i am surprised he isnt using a mullet as a cigarette holder while doing the backstroke in the storm surge


OMG...stop it, you're killing me!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
1658. Patrap
NEXRAD Radar
Brownsville, Storm Total Surface Rainfall Accumulation Range 124 NMI


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what does it mean, a closed eye. what is the implication of a closed eye versus an open one?
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Quoting Tazmanian:



broingcaster
LMAO!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
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90mph winds at the 5pm advisory according to Mike on the weather channel
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1652. IKE
NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORIES...600 PM CDT AND 800 PM CDT.
NEXT COMPLETE ADVISORY...1000 PM CDT.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Hope nobody in Texas has a flood insurance policy that came up for renewal this month. Congress still hasn't re-authorized the program.

Those whose policies expired in June are now in limbo.

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Update for Brownsville - at 3:05 CDT I measured sustained winds at 27mph with a gust to 36mph. Still not even TS strength - but a notable increase from 2pm. At the moment it's a little calmer...
Member Since: September 12, 2008 Posts: 0 Comments: 74
4:00 PM CDT Wed Jun 30
Location: 24.5°N 96.8°W
Max sustained: 90 mph
Moving: W at 13 mph
Min pressure: 959 mb
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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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