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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1898. leo305
NHC-

"Will be a CAT 2, may approach CAT 3 intensity, but thankfully its going to make landfall in 3 hours"
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Live webcam walking around Port Isabel.

Carboneras, MX is going to get hit pretty hard from this.
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Very beautiful cane!! Looking a bit stretched out northeast to southwest at the moment. Is this due to the land interaction? I will have tracking withdrawal after this storm dissipates over land until the next storm begins.
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1894. Patrap
Member Since: July 3, 2005 Posts: 428 Comments: 129780
Alex taps the moisture of two oceans across an entire hemisphere.

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Quoting AstroHurricane001:


Rapid intensification, because it's approaching shallower warm water and the CORE is very tight and compact.

It's actually approaching slightly cooler SSTs.

Ehh, issue of scale.
It's actually been in slightly cooler SSTs for a while now.



If this is correct...
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First pinhole eye Ive seen in a while.

Member Since: June 9, 2007 Posts: 4 Comments: 15950
Quoting JamesSA:

Maybe they'll make him an honorary Cat 2.


Sure. like they should have made IKE an honorary cat 3.
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UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 30 JUN 2010 Time : 204500 UTC
Lat : 24:26:39 N Lon : 96:55:13 W


CI# /Pressure/ Vmax
4.8 / 973.5mb/ 84.8kt


Final T# Adj T# Raw T#
4.8 6.0 6.0


Latitude bias adjustment to MSLP : -0.1mb

Estimated radius of max. wind based on IR :N/A km

Center Temp : -42.1C Cloud Region Temp : -71.1C

Scene Type : EYE

Positioning Method : SPIRAL ANALYSIS

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF
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Quoting FLdewey:


LOL... no you see a guy in a silver suit wearing a full face helmet stumbling around. If you were watching a few mins ago you saw a guy in the background riding his bike in shorts wondering what the bomb squad is doing. Too funny.


Link? I always enjoy the CycloneOz antics...
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Quoting AstroHurricane001:


Flight-level?



sorry dont no how too read what the recone say better ask a pro for tht i this post what they find
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Quoting F4PHANTOM:
Wadsworth IS NOT in Harris County.


I am only the messenger. :-)

I have no idea where Wadsworth is, actually! :-)

It was from a local storm report from the local NWS. :-)
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1882. IKE
Stadium affect???
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1881. leo305
For comparison Katrina was 992MB with 80MPH winds in SFL

While Alex is 955MB with 90MPH winds
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Quoting IKE:


Talk about spinning up.


Rapid intensification, because it's approaching shallower warm water and the CORE is very tight and compact.
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Quoting atmoaggie:

Winds wildly variable, pressure still trending down, of course, at Port Isabel:


Water levels cannot have peaked yet...or maybe they have.




Okay, trying again, those pics are apparently very temporary.

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The Great Spot of Earth.
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Quoting Stormchaser2007:
955mb

9mb to tie

I think Recon may leave.



they will fly though the NE quadrant first
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Quoting Stormchaser2007:
June or September?


Beautiful satelite pic.
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Quoting MiamiHurricanes09:
Audrey had a minimum central pressure of 946mb at peak intensity.


Which is why I said second strongest lol. Anyway Audrey's minimum central pressure is widely disputed, some say it's 938 or 940, but yeah, 946 is the most widely agreed one.
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Quoting Stormchaser2007:
June or September?


Ike season.
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2 1/2 months till full throttle (dangerous Canes to come)
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Alex is looking much better the last few frames..About to add a pic to my name finally XD
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1869. KEEPEROFTHEGATE (Mod)
01L/H/A/C2
MARK(APPROACHING LANDFALL)
24.6N/97.1W
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1868. IKE
Quoting atmosweather:
000
URNT12 KNHC 302132
VORTEX DATA MESSAGE AL012010
A. 30/21:14:30Z
B. 24 deg 21 min N
096 deg 56 min W
C. 850 mb 1042 m
D. 80 kt
E. 350 deg 11 nm
F. 079 deg 94 kt
G. 351 deg 13 nm
H. 955 mb
I. 18 C / 1524 m
J. 22 C / 1522 m
K. 21 C / NA
L. CLOSED
M. C10
N. 12345 / 8
O. 0.02 / 1 nm
P. AF304 1201A ALEX OB 18
MAX FL WIND 96 KT NE QUAD 16:51:20Z


Talk about spinning up.
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955mb

9mb to tie

I think Recon may leave.
Member Since: June 9, 2007 Posts: 4 Comments: 15950
1866. leo305
it looks like a CAT 3, and the pressure is conducive of a CAT 3 hurricane.. but the pressures around it are relatively low, so it can only pick up winds up to CAT 2 intensity at the moment, but the pressure should drop pretty quickly from now till landfall as the eye is now closed, and continues to look better/tighten
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1865. JamesSA
Quoting CybrTeddy:
82 knots = 94.3 only less than 1 mph short of Category 2. IMO NHC will make Alex a Category 2 at 7 pm EDT.

Maybe they'll make him an honorary Cat 2.
Member Since: August 17, 2009 Posts: 0 Comments: 579
Quoting Stormchaser2007:
...pinhole



Poster Image.
Member Since: May 15, 2010 Posts: 0 Comments: 61
1863. IKE
Quoting AstroHurricane001:


Grr, this looks way stronger than cat. 1!


Got to be a cat 2....
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Quoting Tazmanian:
the HH this found winds at 92kt


Flight-level?
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Quoting Stormchaser2007:


Wow, it's in freefall mode.
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June or September?
Member Since: June 9, 2007 Posts: 4 Comments: 15950
Alex is now officially the strongest June hurricane since Alma in 1966.
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000
URNT12 KNHC 302132
VORTEX DATA MESSAGE AL012010
A. 30/21:14:30Z
B. 24 deg 21 min N
096 deg 56 min W
C. 850 mb 1042 m
D. 80 kt
E. 350 deg 11 nm
F. 079 deg 94 kt
G. 351 deg 13 nm
H. 955 mb
I. 18 C / 1524 m
J. 22 C / 1522 m
K. 21 C / NA
L. CLOSED
M. C10
N. 12345 / 8
O. 0.02 / 1 nm
P. AF304 1201A ALEX OB 18
MAX FL WIND 96 KT NE QUAD 16:51:20Z
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Quoting ChillinInTheKeys:
Oz is back out of the capsule. Sounds like he's dying.
link please.
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Quoting Hurricanes101:


you think he can make it?


Probably not.

It would be insane if he does.
Member Since: June 9, 2007 Posts: 4 Comments: 15950
Quoting Stormchaser2007:
...pinhole

That's beautiful.
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Quoting victoriahurricane:


That reading was suspect, the official highest found was 77 knots.


Grr, this looks way stronger than cat. 1!
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1852. IKE
Quoting Stormchaser2007:
...pinhole



Wow. I've got those chills back again....what a system!
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Quoting Hurricanes101:


you think he can make it?
If it had 12 more hours over water yes, but at this point, no.
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Storm totals

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
429 PM CDT WED JUN 30 2010

...UPDATED RAINFALL TOTALS AND WIND GUSTS...

THE FOLLOWING ARE THE MOST CURRENT STORM TOTALS AND WIND GUSTS
FROM A COMBINATION OF AUTOMATED OBSERVING SITES...MESO
NETWORKS...AND COOPERATIVE AND PUBLIC OBSERVERS. WE THANK ALL
THOSE PROVIDING RAPID UPDATES THROUGH THE STORM.

RAINFALL

LOCATION COUNTY RAINFALL (IN)
WESLACO EOC HIDALGO 7.00
BROWNSVILLE EOC CAMERON 6.00
BROWNSVILLE/AIRPORT CAMERON 5.20
HARLINGEN/VALLEY CAMERON 1.87
MCALLEN/MILLER HIDALGO 3.73
BAYVIEW/CAMERON CO CAMERON 3.61
SOUTH PADRE ISLAND CAMERON 4.17
WESLACO/MID VALLEY HIDALGO 4.86
EDINBURG HIDALGO 3.95
FALFURRIAS/BROOKS CO BROOKS 1.82
HEBBRONVILLE/JIM HOGG CO JIM HOGG 0.88
ZAPATA ZAPATA 0.39
SANTA ANA/LOWER RGV NWR HIDALGO 3.29
ATASCOSA/LOWER RGV NWR CAMERON 3.39
SAN MANUEL/LOWER RGV NWR HIDALGO 2.86
FALCON LAKE/UPPER RGV NWR ZAPATA 0.99
MATAMOROS TAMPAULIPAS, MX 9.00

PEAK WINDS

LOCATION
SOUTH PADRE ISLAND CAMERON 54 MPH AT 1255 PM
BAYVIEW/CAMERON COUNTY CAMERON 52 MPH AT 911 AM
BROWNSVILLE/AIRPORT CAMERON 48 MPH AT 352 PM
HARLINGEN/VALLEY CAMERON 47 MPH AT 414 PM
MCALLEN/MILLER HIDALGO 48 MPH AT 142 PM
WESLACO HIDALGO 41 MPH AT 345 PM
EDINBURG HIDALGO 41 MPH AT 345 PM
ZAPATA ZAPATA 32 MPH AT 345 PM
FALFURRIAS/BROOKS CO BROOKS 31 MPH AT 1146 AM
HEBBRONVILLE/JIM HOGG CO JIM HOGG 31 MPH AT 341 PM

NOTE: PEAK WINDS WERE LIKELY MUCH HIGHER IN EMBEDDED TORNADOES
REPORTED EARLIER TODAY IN PORT ISABEL...WEST OF BROWNSVILLE...AND
NORTH OF RAYMONDVILLE. AN UNOFFICIAL RAINFALL REPORT NEAR THE
BROWNSVILLE AIRPORT WAS MORE THAN 6 INCHES AS OF 130 PM. SOUTH
PADRE ISLAND RAINFALL INCLUDES ONLY TODAYS REPORTED AMOUNT.
MCALLEN/MILLER PEAK WIND REPORT OCCURRED ON THE 29TH.

ADDITIONAL PEAK WINDS AND RAINFALL REPORTS WILL BE AVAILABLE EVERY
COUPLE OF HOURS OR SO.
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Here in Brownsville, still have only recorded a gust of 36.0mph (4:05pm cdt)... part of me wishes I'd stayed on South Padre Island, but the logical part is glad I was cautious... as at the time I made the decision, Alex was still moving at a B-line toward the STX coast and there was already significant inland flooding of the streets there.
Member Since: September 12, 2008 Posts: 0 Comments: 75
As of 4PM(est), Storm Intensity Estimates:

SATCON (2mem): MSLP = 960 hPa MSW = 87 kt
ADT: 977 hPa 80 kt Scene: EYE
CIMSS AMSU: 955 hPa 94 kt Bias Corr: 0 (TPC)
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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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