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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Quoting beell:


It a bufkit sounding.
2.315"

Cool, thanks!

Quoting homelesswanderer:
Ike looked kinda weird here. Never seen another like that. But I havent seen many anyway. Sorry blurry.



Check out the archives on this page, you'll find all sorts of cool imagery here, like this:

Member Since: Posts: Comments:
Quoting angiest:
Are we seeing core collapse? The radar presentation just got a lot worse.

no its a EWRC
1344. Patrap

616
WFUS54 KCRP 301919
TORCRP
TXC355-409-302000-
/O.NEW.KCRP.TO.W.0016.100630T1919Z-100630T2000Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
219 PM CDT WED JUN 30 2010

THE NATIONAL WEATHER SERVICE IN CORPUS CHRISTI HAS ISSUED A

* TORNADO WARNING FOR...
NORTH CENTRAL NUECES COUNTY IN SOUTH TEXAS...
SAN PATRICIO COUNTY IN SOUTH TEXAS...

* UNTIL 300 PM CDT

* AT 216 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 10 MILES
NORTHEAST OF TAFT...OR 9 MILES SOUTH OF WOODSBORO...MOVING
SOUTHWEST AT 40 MPH.

* LOCATIONS IMPACTED INCLUDE...
TAFT...
SINTON...
ODEM...
EDROY...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM CDT WEDNESDAY EVENING
FOR CENTRAL TEXAS.
Member Since: July 3, 2005 Posts: 419 Comments: 127381
1343. Astinus
Quoting gnshpdude:
Ok, Explain to me why the NHC has not shifted the track north considering Alex is further north then projected at landfall now!!


The NHC only updates the forecast track every six hours during its complete advisories. The next one is at 5pm EDT.
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1342. ginajo
- Thanks Patrap, I am in the Matagorda County area, family in Sweeny, Van Vleck.
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Quoting AstroHurricane001:


What's PW?


Percipitable water
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1339. angiest
Are we seeing core collapse? The radar presentation just got a lot worse.
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Quoting TexasHurricane:


Hi Homeless... getting any rain? Not much here. I was expecting a decent amount but it has been very light. Unless it will get stronger later...not sure.


Just a slow steady light rain. Almost putting me to sleep. :)
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1337. Asta
DVORAK- sure is takin' his time to go inland...
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1336. ncstorm
Quoting Floodman:


There's nothing that says you can't link to a banned member's content; loosen up a little!

Now, as for Skepticall2 calling people haters because they have something diparaging to say about OZ, that's a little over the top as well...


didnt tampaspin get banned for linking his website on the blog?
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1334. Patrap
Member Since: July 3, 2005 Posts: 419 Comments: 127381
Quoting Floodman:
Geez, guys...here it is:

Nut job in the rain


It's off air for me..
Member Since: July 7, 2008 Posts: 2 Comments: 3237
http://www.ustream.tv/channel/live-severe-weather-webcam
Member Since: July 14, 2008 Posts: 1 Comments: 9628
RI at landfall? (again)
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Quoting homelesswanderer:
Ike looked kinda weird here. Never seen another like that. But I havent seen many anyway. Sorry blurry.




Hi Homeless... getting any rain? Not much here. I was expecting a decent amount but it has been very light. Unless it will get stronger later...not sure.
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1329. Drakoen
Alex pressure decreases 2mb
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1328. Asta
GOES WATER VAPOR G.O.M.-LINK

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Link

Here ya go teddy
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting beell:


It a bufkit sounding.
2.315"


What's PW?
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Geez, guys...here it is:

Nut job in the rain
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting HurricaneNewbie:
Just an observation from a layman. Alex has made landfall already. That little area called the eye is not the worst part of the storm. The area just outside the eye is the real trouble spot. Looking at the radar some areas have already taken a pounding from the rain and will continue to do so.Those in the areas that are getting pounded the time to evacuate was yesterday. If you are reading this blog and are in the storm path shut your computer down and evacuate please. I do not want to see your corpse on the local news floating in the flood waters.

Thanks


You're right that the eyewall is the worst part, but you're wrong in that the eyewall hasn't touched land yet, and that the definition of landfall is when the COC hits land. They are definitely feeling the effects of the storm though! Conditions continue to deteriorate, so I understand what you're saying!
Member Since: July 7, 2008 Posts: 2 Comments: 3237
1323. NRAamy
1307. FLdewey 12:15 PM PDT on June 30, 2010
I'm sorry he needs a new rainsuit... he looks like a baked potato.



hahahahahahahaha!

:)
Member Since: January 24, 2007 Posts: 317 Comments: 31946
Ike looked kinda weird here. Never seen another like that. But I havent seen many anyway. Sorry blurry.


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1321. beell
Quoting 1900hurricane:

Woah, how high is the PW in that sounding???


It a bufkit sounding.
2.315"
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El Te.... not the place to be, on a barrier island..



AOI
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Hi all! I've been lurking here for a couple days and haven't really posted since 2007. Got a great tip: if you have an iphone, get the app called "5-0 Radio" (it's free) and listen to Cameron County Public Safety. That's where Brownsville is located.

You can hear firefighters and police officers chatting away. I've heard several reports of impassible roads, buildings that may collapse, and transformer explosions.

It gives you a really cool, real-time feel of what it's like on the ground.
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Quoting putintang3:
. TexasHurricane 7:13 PM GMT on June 30, 2010
Are there any models showing any other storms brewing soon? If so, where?


Lets do one at a time please


just curious, that is all....
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1317. Asta
LINK
Member Since: Posts: Comments:
Just an observation from a layman. Alex has made landfall already. That little area called the eye is not the worst part of the storm. The area just outside the eye is the real trouble spot. Looking at the radar some areas have already taken a pounding from the rain and will continue to do so.Those in the areas that are getting pounded the time to evacuate was yesterday. If you are reading this blog and are in the storm path shut your computer down and evacuate please. I do not want to see your corpse on the local news floating in the flood waters.

Thanks
Member Since: Posts: Comments:
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 30th day of the month at 19:09Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 304)
Storm Number & Year: 01L in 2010
Storm Name: Alex (flight in the North Atlantic basin)
Mission Number: 12
Observation Number: 09
A. Time of Center Fix: 30th day of the month at 18:50:20Z
B. Center Fix Coordinates: 24°23'N 96°27'W (24.3833N 96.45W)
B. Center Fix Location: 125 miles (201 km) to the SSE (149°) from Brownsville, TX, USA.
C. Minimum Height at Standard Level: 1,103m (3,619ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 65kts (~ 74.8mph)
E. Location of the Estimated Maximum Surface Wind: 14 nautical miles (16 statute miles) to the E (97°) of center fix
F. Maximum Flight Level Wind Inbound: From 178° at 74kts (From the S at ~ 85.2mph)
G. Location of Maximum Flight Level Wind Inbound: 13 nautical miles (15 statute miles) to the E (95°) of center fix
H. Minimum Sea Level Pressure: 960mb (28.35 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,521m (4,990ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,523m (4,997ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 20°C (68°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open in the southeast
M. Eye Shape & Diameter: Circular with a diameter of 9 nautical miles
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Flight Level Wind: 96kts (~ 110.5mph) in the northeast quadrant at 16:51:20Z
Maximum Flight Level Wind Outbound: 87kts (~ 100.1mph) in the northwest quadrant at 18:55:20Z

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1314. Drakoen
Alex has made a noticeable turn towards the WNW on radar and visible imagery
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Can anyone provide the ATCF link that shows when storms are renumbered, ect.
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Quoting Floodman:


OH NO...that was simply wrong, Amy!


Are we talking about Alex's dry EWRC?
Member Since: August 30, 2008 Posts: 8 Comments: 2835
1311. NRAamy
I love JF.....he knows it....

:)

Member Since: January 24, 2007 Posts: 317 Comments: 31946
Quoting beell:
17Z RUC Modeled Sounding
Valid 1PM CDT
Ciudad Victoria
(Approx 90 miles inland, west of La Pesca, MX

Photobucket

Woah, how high is the PW in that sounding???
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. TexasHurricane 7:13 PM GMT on June 30, 2010
Are there any models showing any other storms brewing soon? If so, where?


Lets do one at a time please
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I wonder what is that spin just east of South Florida??,I believe it could be a upper level low?,is trying to get more clouds into the rotation,may be this is the small feature that some of the models predicted few days ago out of the East coast of Florida,any comments on this??,just to change the subject from dangerous!! Hurricane Alex,thanks!
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Quoting NRAamy:
Thats just how I am, un loose I guess.

Metamucil might help....

:)


OH NO...that was simply wrong, Amy!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting RitaEvac:
need Oz's link please

Yeah everyone's talking about it and no one bothered to link it... whatever "it" is.
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ok 1900hurricane the top one is Ike of 08 and the bottom it Alex you know its more fun if you take off the stamp dates and the country/boarder lines
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Quoting Gorty:
If the NOGAPS is correct with the Carribean system, do you think it could come up here where I am Southern New England?

I know we are just waiting on a hurricane to come any season.


If New England gets one it is going to be this to be this year. But Hurricane Bill just missed last year. Maybe that was the one! Who knows tho. It's been so long.
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1302. Drakoen
Alex is taking in some continental dry air which is evident on both visible and radar images.

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1301. NRAamy
Thats just how I am, un loose I guess.

Metamucil might help....

:)
Member Since: January 24, 2007 Posts: 317 Comments: 31946
Quoting Asta:
LINK


Is this a rain band that could be coming to SE TX soon?
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1299. snotly
Quoting gnshpdude:
Ok, Explain to me why the NHC has not shifted the track north considering Alex is further north then projected at landfall now!!


From the NHC....

THE CURRENT WEAKNESS IN
THE SUBTROPICAL RIDGE TO THE NORTH OF THE CYCLONE SHOULD BE
REPLACED BY A RIDGE SOON. THIS FLOW PATTERN SHOULD FORCE ALEX
ON A MORE WESTWARD TRACK LATER TODAY AS INDICATED IN THE OFFICIAL
FORECAST. IN FACT...MOST OF THE DYNAMICAL GUIDANCE FORECAST A SHARP
TURN TO THE WEST OR EVEN SOUTH OF DUE WEST DEPENDING UPON THE
FORECAST STRENGTH OF THE RIDGE IN EACH MODEL. THIS TRACK SHOULD
BRING THE CORE OF THE HURRICANE TO THE COAST WITHIN THE WARNING
AREA LATE TONIGHT OR EARLY THURSDAY.
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Quoting snotly:
Any chance Alex is forming two eye walls? Looks like inner convection ring might choke itself off soon.


If that is a concentric eyewall, and it takes over, that would make the hurricane winds much larger in diameter.
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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.