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 Hurricanes101:


People don't seem to learn

It is sad to have to waste time reading posts about serving crow and who was right and wrong at this time when this storm is about to make landfall

These people show very little class, even if it is just them joking around

I hope everyone in Northern Mexico and South Texas are truly ready for this, Alex should be making landfall within the next 3-6 hours now
Hopefully we don't suffer any casualties, so let's hope for the best.

Looks like Alex isn't done strengthening, imo. He might make it to CAT 2 status before landfall in a couple of hours.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1446. SamTeam
Quoting MILLERTIME1:
I wonder how big of a town San Fernando is? Looks like it is going to take a pretty good hit.


I have a frined who has a 'fishing house' down there; small fishing village type, 1 store, a flashing yellow light, gas station, boat storage & RV park & that is just about the extent of San Fernando!
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1445. SeALWx
Quoting 47n91w:


At 0.5 degrees elevation, base velocity is measuring at increasing heights away from the radar dome. I'm seeing the highest winds between 5000 and 7000 feet above ground level via radar. Surface winds are not sampled by even the lowest tilt of WSR-88D.

TDWR has a lower tilt, between 0.1 degrees and 0.3 degrees, but even that beam rises above ground level.


Exactly my point. The beam is traveling at an upward angle as the curvature of the earth falls away from the beam angle. It's just not possible to 'see' the near ground environment with radar.
Member Since: April 2, 2010 Posts: 0 Comments: 196
1444. angiest
Notice the eye is no longer black:

filling eye
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Looks like Alex is moving just north of West to me. The high has probably catches it and now steering it westward to just south of the borderline of Mexico and Texas.
Member Since: July 1, 2008 Posts: 13 Comments: 7432
Live webcam from Port Isabel. He's suiting up and getting ready to walk around with the webcam.

Looks like Alex will be on shore with in the next 6 hours. He sure picked up speed this morning/afternoon.
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1441. CCkid00
Quoting duajones78413:
I see bands from this storm as far as Dallas

we are getting heavy bands of rain with some good gusts of wind, as far as Baton Rouge, La.
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Quoting kabloie:
Recon headed NE for one last shot at Alex' core. ~15 minutes
They are going to try and make a total of 5 passes through the center. The weatherman with NBC 15 is on board and was filming live before flight and had reported that the crew wanted to get as much info as possible because they will not be going back in again after this flight.
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Quoting Tazmanian:
whats next too track when this is out of the way


91W.INVEST
Member Since: September 23, 2005 Posts: 14 Comments: 11305
1438. angiest
Quoting 47n91w:


At 0.5 degrees elevation, base velocity is measuring at increasing heights away from the radar dome. I'm seeing the highest winds between 5000 and 7000 feet above ground level via radar. Surface winds are not sampled by even the lowest tilt of WSR-88D.

TDWR has a lower tilt, between 0.1 degrees and 0.3 degrees, but even that beam rises above ground level.


And no TDWR in Brownsville. :S
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Quoting MiamiHurricanes09:
Probably one of the most intelligent posts of the day. Anyways, landfall in 4-6 hours seems likely if not earlier.


People don't seem to learn

It is sad to have to waste time reading posts about serving crow and who was right and wrong at this time when this storm is about to make landfall

These people show very little class, even if it is just them joking around

I hope everyone in Northern Mexico and South Texas are truly ready for this, Alex should be making landfall within the next 3-6 hours now
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Quoting Hardcoreweather2010:
3D radar shot of Alex

amazing! looks exactly like a hurricane symbol.
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1435. 47n91w
Quoting RecordSeason:
According to the Radar estimates, this storm is currently MUCH stronger than the offical NHC classification.

Max positive velocity is sustained at 100kts and max negative velocity is fluctuating between 100kts and 117kts on both base and mean velocity estimates.

Base velocity

Mean Velocity


At 0.5 degrees elevation, base velocity is measuring at increasing heights away from the radar dome. I'm seeing the highest winds between 5000 and 7000 feet above ground level via radar. Surface winds are not sampled by even the lowest tilt of WSR-88D.

TDWR has a lower tilt, between 0.1 degrees and 0.3 degrees, but even that beam rises above ground level.
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Check out NY on the Wunderground GFS run for July 8, 2010

I would have posted the image, but don't know how.
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Quoting duajones78413:
I see bands from this storm as far as Dallas


Yes, south of Interstate 20
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1432. angiest
The eye looks like it is filling in.
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The only reason OZ has his variety show is to allow those that continue to watch to be entertained. Nothing of value in watching waves crash. JMHO
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Hey Taz, which flavor of crow are you eating today, honey bbq or chipotle?
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...a closer look at Alex using UV filters !

Member Since: February 19, 2007 Posts: 0 Comments: 239
Hello,

Yes youre right land in 4-5 hours.

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1427. kabloie
Recon headed NE for one last shot at Alex' core. ~15 minutes
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Quoting rareaire:
Tampa Spin gets banned but Oz has his own variety show? Maybe some consistency would be nice.


Oz has been permabanned, where have you been?
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I see bands from this storm as far as Dallas
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1424. angiest
Quoting HurricaneNewbie:


Drinking in a hurricane would be more appropriate. Just use a straw to prevent waste.


Hurricanes are good drinks.
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1423. JamesSA
Quoting FLdewey:
Dreams of a Texas landfall go up in smoke :D

It is a Mexico, Texas, Louisiana, and Mississippi landfall all in one! Everyone is getting some of this one.
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Right now, my radar shows over the last 3 hours, what appears to be the center of the eye of Alex has moved from 24.38/-96.29 to 24.4/96.67. so .4W and .02N, so defintely nearly a due west movement. I'm gonna call for landfall in 5-6 hours around 24.65/97.7. This is my first ever prediction so take it easy on me. I'm going to hold off on intensity forecasts at the moment. Still learning as we go.
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whats next too track when this is out of the way
Member Since: May 21, 2006 Posts: 5091 Comments: 115437
1420. Patrap
Quoting TampaWeatherBuff:


But perverse fantasies of a Florida landfall NEVER die! ;)

OMG...

LOL
Member Since: July 3, 2005 Posts: 427 Comments: 129424
Quoting WatchingThisOne:


It's looking like 3 hours from now looking at WV sat of the eye, in the range of 6 to 7:30 Eastern time.

Ugh I got to go to work at 6, I'll miss it.
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1418. Patrap
NEXRAD Radar
Brownsville, Storm Total Surface Rainfall Accumulation Range 124 NMI

Member Since: July 3, 2005 Posts: 427 Comments: 129424
Quoting Hurricanes101:
At a time a storm is heading towards landfall, it is not the time to brag about who was wishing or wrong

Those types of posts are useless in this stage of the game


Anyway certainly does seem like Alex is moving westward now, landfall in about 6 hours I would say
Probably one of the most intelligent posts of the day. Anyways, landfall in 4-6 hours seems likely if not earlier.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting MiamiHurricanes09:
Landfall might come sooner than previously anticipated.


It's looking like 3 hours from now looking at WV sat of the eye, in the range of 6 to 7:30 Eastern time.
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Quoting FLdewey:
Dreams of a Texas landfall go up in smoke :D


But perverse fantasies of a Florida landfall NEVER die! ;)
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Latest reports from Cameron County (Brownsville) EOC:
- various intersections flooded in city of brownsville...police blocking traffic
- parking lots flooded
- power outages near eoc building
- various transformers on fire...power company responding
- sandbag distribution center closed due to rain/wind

The above was picked up from radio chatter between EOC and police officers.
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2 inches of rain in Corpus Christi so far. Winds out of the north with occasional gusts to around 30 mph.
I wonder how much rain we will get out of this system
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Tampa Spin gets banned but Oz has his own variety show? Maybe some consistency would be nice.
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Quoting NRAamy:
Quoting Floodman:
Geez, guys...here it is:

Nut job in the rain



hahahahahahahahahaha!

:)


LOL...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
1409. Patrap

630
WFUS54 KBRO 301942
TORBRO
TXC061-302015-
/O.NEW.KBRO.TO.W.0014.100630T1942Z-100630T2015Z/

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

THE NATIONAL WEATHER SERVICE IN BROWNSVILLE HAS ISSUED A

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

* UNTIL 315 PM CDT

* AT 241 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
A TORNADO MOVING ONSHORE ABOUT 20 MILES EAST OF SAN
BENITO...MOVING WEST AT 50 MPH.

* THE TORNADO WILL BE NEAR...
BUENA VISTA.
LANTANA.
HARLINGEN VALLEY AIRPORT.
HARLINGEN.
PALM VALLEY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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: 427 Comments: 129424
1408. SeALWx
Quoting RecordSeason:
According to the Radar estimates, this storm is currently MUCH stronger than the offical NHC classification.

Max positive velocity is sustained at 100kts and max negative velocity is fluctuating between 100kts and 117kts on both base and mean velocity estimates.

Base velocity

Mean Velocity



But at what height? Radar plane increases in altitude as distance from the radar site increases.
Member Since: April 2, 2010 Posts: 0 Comments: 196
At a time a storm is heading towards landfall, it is not the time to brag about who was wishing or wrong

Those types of posts are useless in this stage of the game


Anyway certainly does seem like Alex is moving westward now, landfall in about 6 hours I would say
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Direction calculated from last two vortex messages = 285 deg.
Member Since: September 23, 2005 Posts: 14 Comments: 11305
3D radar shot of Alex
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1404. Patrap
NEXRAD Radar
Brownsville, Storm Relative Mean Radial Velocity 1.45 Degree Elevation Range 124 NMI


Member Since: July 3, 2005 Posts: 427 Comments: 129424
I just watched the longest L. L. Bean commercial ever...oh, wait, that was just Sidel on the weather channel..shees..this channel is like hurricane for dummies.
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Quoting Hurricanes101:


I disagree, look at how the coastline is shaped in that area, I think a move further north would bring the center in sooner
Landfall was supposed to be at 1AM EDT, that's 9 hours from now. I doubt we'll see landfall 9 hours from now, maybe in 4-6 hours.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1400. SeALWx
(Moved to next page)
Member Since: April 2, 2010 Posts: 0 Comments: 196
Alex is moving west; perhaps slightly WSW.
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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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