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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Alex seems to have slowed down just a bit over the last hour...about 12mph down from 15.
Member Since: Posts: Comments:
Quoting Floodman:


Hey, brother! How's things?


Ju8st poked my head in for a minute to catch up from this morning. Why is the NHC track showing a SW movement before the WNW move to landfall? From what I've read in the last two pages of the blog, it appears that either that SW movement is already past or that the NHC was mistaken (which would alter the expected point of landfall). Fill me in, brudda.
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1096. MahFL
What is Oz's website ?
Member Since: Posts: Comments:
Quoting bingcrosby:
What in the world???....1pm advisory.



Looks like Alex will end up just slightly north of the edge of the cone of uncertainty.

Quoting JamesSA:
That's called sticking to your forecast, right or wrong! What are they thinking, and why are they bent in causing deaths in Brownsville?


They need to do a direct NW adjustment in their forecast, and pay less attention to the models and more on the rate of strengthening based on satellite imagery and radar! Anyone want to email the NHC?
Member Since: Posts: Comments:
1094. Patrap
Quoting hamla:


paltrap
after going thru so many storms since 1962 in la. i have only 1 thought for all those who think that theirr personal possions are more important than their lives is when the man sayss geet the hell out of dodge leave.i have seen it all in my 71 years and you might loosse personal things you cant loose your life.
thess storms weathe tropical/hurricanes are not something to take for granite.i have been thru btsy,cammile,ivan,andrew,katrina rita,gustav and so many otherss but imm still here and if i would have stayed i might not be posting this today.use common sense and leave all can be replaced except your life

PLEAse pay attention and do what tthe athurotties say to do at least you can come back
good luck to all
hamla
n11rg
rick
bay st louis ms


Fine stuff there from a Good source.

Memory..

Thanks for that.

We have a Home off of 90 right at Louise's Gift Shop near Blossman Gas.

So I can relate..

Betsy was my first eyewall dance,but I was a mere 5.5 then.
Member Since: July 3, 2005 Posts: 426 Comments: 128749
1093. fire635
Quoting WaterWitch11:
bill read from nhc says landfall at midnight


I think that will be just about right
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I like the new one better.
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Quoting weatherboyfsu:
It appears now that ALEX has made its move more to the west with an eye looking back at us. If this continues, it will lessen the threat for Brownsville and deepen the threat for NE Mexico. Lots of flooding and surge damage for Mexico unfortunately......


I don't think the coast is particularly populated along there. As for flooding, both sides of the Rio Grande Valley could take it pretty hard.
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going exactly where Emily went in 05
Member Since: July 14, 2008 Posts: 1 Comments: 9630
Quoting Patrap:
A good amount of dryer air is in the South Side of the Circ just Outside the Eyewall..

Thats gonna have a role to Play this afternoon.



just because convection lacks there, doesn't mean its from dry air, the hurricane just isn't producing any lift or convergence there.

Somehow I doubt a PW reading between 2.5 and 3.00 inches throughout the storm has anything to do with dry air... Thats about as much moisture the air can possibly hold...
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1087. IKE
Bill Reed....NHC director on TWC...."could get to at least category 2 before landfall".
Member Since: June 9, 2005 Posts: 23 Comments: 37858
bill read from nhc says landfall at midnight
Member Since: August 11, 2008 Posts: 3 Comments: 1638
1085. angiest
I'm seeing a rather pronounced westward wobble on the radar now.
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1084. fire635
Quoting primadonnagirl:
alex is still going north


I dont know what youre looking at but "Going north" would not be the direction I would call it.... at best its going WNW right now.
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1081. IKE
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1080. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 128749
dont need long range radar anymore, he's closing in

Member Since: July 14, 2008 Posts: 1 Comments: 9630
1078. Asta
LINK
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It appears now that ALEX has made its move more to the west with an eye looking back at us. If this continues, it will lessen the threat for Brownsville and deepen the threat for NE Mexico. Lots of flooding and surge damage for Mexico unfortunately......
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1075. angiest
558 - I caught a TVS for what I think is that tornado on the radar a little bit ago. It was rather prominent in the SRV.
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1074. hamla
Quoting Patrap:
A good amount of dryer air is in the South Side of the Circ just Outside the Eyewall..

Thats gonna have a role to Play this afternoon.


paltrap
after going thru so many storms since 1962 in la. i have only 1 thought for all those who think that theirr personal possions are more important than their lives is when the man sayss geet the hell out of dodge leave.i have seen it all in my 71+years and you might loosse personal things you cant loose your life.
thess storms weathe tropical/hurricanes are not something to take for granite.i have been thru btsy,cammile,ivan,andrew,katrina rita,gustav and so many otherss but imm still here and if i would have stayed i might not be posting this today.use common sense and leave all can be replaced except your life

PLEAse pay attention and do what tthe athurotties say to do at least you can come back
good luck to all
hamla
n11rg
rick
bay st louis ms
Member Since: Posts: Comments:
1072. Levi32
Quoting DrakoenG:
good job, levi. :)


Thanks.
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Quoting katadman:


If he's not, he should be.


Hey, brother! How's things?
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just to see if i can post this radar. its awsome. patrap you are right, how bout that radar
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1068. GBguy88
Quoting IKE:
Should be making landfall by sunset.


And good thing, too. That eyewall is really sealing things up. Another day over water and this could be much nastier than it is (I know...duh, right?).
Member Since: August 22, 2008 Posts: 0 Comments: 483
Quoting Patrap:
But Hey,

..how bout dat radar Huh?





Wow, rapid strengthening just in the past 90 minutes.

I expect a cat. 2 by 5 pm EDT.
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Quoting CybrTeddy:


NOGAPS caught Alex when the ECMWF did. So we'll see.


good point
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1065. will45
Quoting atmoaggie:
990: And you quoted it for all to see. Lovely.


yea some will never understand
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1064. Patrap

558
WFUS54 KBRO 301802
TORBRO
TXC061-301845-
/O.NEW.KBRO.TO.W.0011.100630T1802Z-100630T1845Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE BROWNSVILLE TX
102 PM CDT WED JUN 30 2010

THE NATIONAL WEATHER SERVICE IN BROWNSVILLE HAS ISSUED A

* TORNADO WARNING FOR...
CENTRAL CAMERON COUNTY IN DEEP SOUTH TEXAS.

* UNTIL 145 PM CDT

* AT 102 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
TORNADO 18 MILES EAST OF PORT ISABEL...MOVING WEST AT 55 MPH.

* THE TORNADO WILL BE NEAR...
SOUTH PADRE ISLAND BY 115 PM CDT.
LAGUNA HEIGHTS BY 120 PM CDT.
HOLLY BEACH BY 125 PM CDT.
LA LEONA BY 135 PM CDT.
LOZANO BY 140 PM CDT.
SAN BENITO BY 145 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM! MOVE INTO THE INTERIOR ROOM ON THE LOWEST
FLOOR OF A STURDY BUILDING...AWAY FROM WINDOWS. COVER YOUR HEAD AND
BODY WITH PILLOWS OR BLANKETS.

PLEASE REPORT TORNADOES OR FUNNEL CLOUDS...WINDS OF 58 MPH OR
HIGHER...AND ANY WIND DAMAGE TO YOUR NATIONAL WEATHER SERVICE IN
BROWNSVILLE BY CALLING 956-504-1432.
Member Since: July 3, 2005 Posts: 426 Comments: 128749
1063. JRRP

i´m out
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Could see this system pop up on July 8th if the ECMWF verifies.
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Quoting 1900hurricane:

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


Other models ore forecasting a small cluster of thunderstorms that could potentially become an area of low pressure near the panhandle of Florida.

http://2.bp.blogspot.com/_ScGjBIDpW5c/TCncaUTdpAI/AAAAAAAABRs/6ODsm3fnAZo/s1600/gfs_ten_072l.gif


http://2.bp.blogspot.com/_ScGjBIDpW5c/TCncdFOGFVI/AAAAAAAABR0/OGceocFFtW8/s1600/gfs_85v_066l.gif
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1060. IKE
Should be making landfall by sunset.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting angiest:


Ahh, I see. It is an *inland* warning, not the same as the coastal warning. I'd be willing to bet the inland warnings are issued by your local weather forecast office and not the NHC.


Yep.
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1057. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 128749
1056. fire635
Quoting F4PHANTOM:
Don't know if it's been discussed, but ECMWF went to Mexico over a week ago and while other models were jumping around all over the place it stayed with it's general track. Good job ECMWF.


It seems as though that's the common denomenator with the ECMWF. As odd as it is when the first runs come out... a week later it ends up doing what the ECMWF says it would do
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Quoting DrakoenG:
do any of the models show a florida hit?


no, just mexico

maybe, we should throw the models out.
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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.

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


The NOGAPS develops this system in around 96-120 hours, but the ECMWF shows it around 216-240hr...so I'm not thinking they are showing the same system.
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1053. angiest
Quoting homelesswanderer:


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.


Ahh, I see. It is an *inland* warning, not the same as the coastal warning. I'd be willing to bet the inland warnings are issued by your local weather forecast office and not the NHC.
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Quoting Floodman:


"Committed" is the word you're looking for


If he's not, he should be.
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Quoting SeniorPoppy:



NOGAPS = dreamcaster


NOGAPS caught Alex when the ECMWF did. So we'll see.
Member Since: Posts: Comments:
1050. JamesSA
Quoting bingcrosby:
What in the world???....1pm advisory.

That's called sticking to your forecast, right or wrong! What are they thinking, and why are they bent in causing deaths in Brownsville?
Member Since: August 17, 2009 Posts: 0 Comments: 579
1048. Patrap
Wait for.it, Ez,

..wait for it..

LOL
Member Since: July 3, 2005 Posts: 426 Comments: 128749

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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.