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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2848. centex
Land disrupting center.
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Recon checking out the eye again, this will be the last time they check it out.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Answer: Cape Verde-type hurricanes typically develop from tropical waves which form in the African savanna during the wet season, then move into the African steppes. The disturbances move off the western coast of Africa and become tropical storms or tropical cyclones within 1,000 kilometres (620 mi) of the Cape Verde Islands, usually in August or September. However, Cape Verde hurricanes have formed as early as July or as late as October. An average of two form per hurricane season.[1]

I bet we get one as defined before August of this year!
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Dean and Felix both had an insane amount of lightning for Hurricanes.
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Quoting 69Viking:


I thought if the wave that they originated from came from Africa that made them a Cape Verde storm???
A Cape Verde storm has to develop into at least a tropical depression within 620 miles of the Cape Verde Islands to be classified as a Cape Verde storm.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
"Too much dry air..."

"Water can't support a major"

"too much shear"

and my own "It's going east"

Looks like EVERYONE eats crow tonight.
Member Since: June 13, 2010 Posts: 0 Comments: 2336
Quoting atmoaggie:

Since that, there have been publications linking lightning in eyewalls to intensification in the following 24(?) hours. There is a correlation to strengthening when lightning occurs in the eyewall.
I am a lightning photographer... I have noticed the absence of lightning in Hurricanes from my experience of living here in Central Florida for over 40 years. However, Tropical storms is a different matter all together. 2004 Tropical Storm Bonnie came very close to central florida and I noted an extraordinary amount of lightning in that storm.

Just my personal observations
Mark
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2841. Asta
Hope everyone in Alex's path stays safe.

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Quoting atmoaggie:
Felix was an absolute tiny beast...


Dean was a beast and a large one too.
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Felix was small, but 175 mph winds. Yikes!!
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2838. Patrap
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Quoting MiamiHurricanes09:
Post 2817.


I thought if the wave that they originated from came from Africa that made them a Cape Verde storm???
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Quoting Eagle101:
Someone was asking about lightning, or the lack of, in hurricanes. I found the following on NASA:

“Actually, says Blakeslee, the reason most hurricanes don't have lightning is understood. "They're missing a key ingredient: vertical winds."

Within thunderclouds, vertical winds cause ice crystals and water droplets (called "hydrometeors") to bump together. This "rubbing" causes the hydrometeors to become charged. Think of rubbing your socked feet across wool carpet--zap! It's the same principle. For reasons not fully understood, positive electric charge accumulates on smaller particles while negative charge clings to the larger ones. Winds and gravity separate the charged hydrometeors, producing an enormous electric field within the storm. This is the source of lightning.

A hurricane's winds are mostly horizontal, not vertical. So the vertical churning that leads to lightning doesn't normally happen.”

The same article also noted that the electric field above Emily, as recorded by instruments on NASA’s ER-2 (U-2), were about 8 kilovolts/meter. Quite a strong field, indeed. They noted this was, indeed, an anomaly.


Link

Very Respectfully,

Jon


Here is an article I read a while back using lightning as a predictor of an approaching hurricane's strengh.
Link
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Quoting hurricaster:
However, Felix was an absolute beast!
Felix was an absolute tiny beast...
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Quoting MiamiHurricanes09:
Recon in route to check it out right before landfall.

Wow, really? Man, if there are any records set, it might be for the number of passes from one mission!

Out of curiosity, does anyone know what the actual record for number of passes is?
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2832. Patrap
Quoting ShenValleyFlyFish:
Floods from Alex have already killed ten people--six in Nicaragua, and two each in El Salvador and Guatemala.
******

From the Dr's post above. I am constantly amazed at the number of folks who come on the blog and start posting away without reading the Dr's post or back reading a bit on the blog to get up to speed.



We dubbed dat,..

"No Look up-itis".
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Quoting Tazmanian:
OMG i see no one on the blog can take a joke lol


Its not remotely funny...
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2830. Drakoen
Quoting AstroHurricane001:


Alex has drifted SW. Which could mean that one of its layers moves over the mountains of Mexico, one shifts into the CONUS and one remains over the BOC, patiently waiting for a chance to pick up convection and reincarnate Alex over the NE Gulf (as some models show).



PINWHEEL EYE!!!!!



Ideally. Not sure if NHC follows that rule though.


The NHC does follow that rule.
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Oz's car just took a dump on him. Go figure. I just heard him light another cig. :)
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2828. Kibkaos
Hello everybody down here in Pearland TX watching Alex in south Texas. I noticed that a couple of models have a piece of energy in the gulf on Saturday. Does anyone have any more information on this?
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2827. centex
Stirring level graphics post would be appreciated.
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12 hours of Brownsville radar. 117 frames.
Not the for the feint of memory, CPU, or bandwidth.
Java loop.

http://rap.ucar.edu/weather/radar/displayRad.php?icao=KBRO&prod=bref1&bkgr=color&endDate=20100701&e ndTime=-1&duration=12
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Quoting StSimonsIslandGAGuy:
Storms first named in the NW Caribbean are not Cape Verde storms.

I don't know the official definition, but I would say at a minimum they have to be named east of 50 or 45 W.
Post 2817.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting JLPR2:
Something is wrong here:

XD


Alex has drifted SW. Which could mean that one of its layers moves over the mountains of Mexico, one shifts into the CONUS and one remains over the BOC, patiently waiting for a chance to pick up convection and reincarnate Alex over the NE Gulf (as some models show).

Quoting Asta:

Gotta laugh or it will make y'a crazy-
Maybe now when we board up our homes we should also wrap it with Saranwrap too! LoL!
unreal.
Alex's eye still peeking just outside the coastline..




PINWHEEL EYE!!!!!

Quoting Drakoen:
The system makes landfall when the absolute center of the system comes on shore.


Ideally. Not sure if NHC follows that rule though.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
2823. IKE
Not much to joke about with Alex.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
However, Felix was an absolute beast!
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OMG i see no one on the blog can take a joke lol
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Floods from Alex have already killed ten people--six in Nicaragua, and two each in El Salvador and Guatemala.
******

From the Dr's post above. I am constantly amazed at the number of folks who come on the blog and start posting away without reading the Dr's post or back reading a bit on the blog to get up to speed.
Member Since: Posts: Comments:
Quoting atmoaggie:

Since that, there have been publications linking lightning in eyewalls to intensification in the following 24(?) hours. There is a correlation to strengthening when lightning occurs in the eyewall.

Dr. Masters reported that there was abundant lightning lining the eye of Hurricane Felix when he was rapidly intensifying.

Link
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Quoting CapeObserver:


What classifies a Cape Verde storm?
Any tropical wave that becomes a tropical cyclone within 1,000 kilometres (620 mi) of the Cape Verde Islands is considered a Cape Verde storm.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
2816. HadesGodWyvern (Mod)
000
WTNT41 KNHC 302036 (that is the UTC timestamp) 30th day of month 20:36 PM UTC
TCDAT1
HURRICANE ALEX DISCUSSION NUMBER 21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012010
400 PM CDT WED JUN 30 2010

--
just pointing it out
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Quoting atmoaggie:

Since that, there have been publications linking lightning in eyewalls to intensification in the following 24(?) hours. There is a correlation to strengthening when lightning occurs in the eyewall.


Thanks...

v/r

Jon
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Quoting Tazmanian:
ALEX is RIP it got in torn up by too march shear MX is safe

P--f
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hey guys can you post me the link to the 18Z nogaps
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And now comes the rain and the rain and the rain....
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Quoting MiamiHurricanes09:
Nope, it isn't a Cape Verde storm.


What classifies a Cape Verde storm?
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Quoting Drakoen:
The eyewall is closing in on the coast
Recon in route to check it out right before landfall.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting AlexEmmett:

hahaha what the hell are u smoking taz




i this like mass with you all
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2807. Patrap
Half the storm is already on Land come the er,"landfall"

Pfftttt
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2806. HadesGodWyvern (Mod)
the public advisories would always use EDT, CDT, AST (depending on the where the cyclone center is located)
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2805. Drakoen
The eyewall is closing in on the coast
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2804. SykKid
LANDFALL JUST MOMMENTS AWAY!
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Quoting angiest:


Thanks.

No problem.
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Quoting Eagle101:
Someone was asking about lightning, or the lack of, in hurricanes. I found the following on NASA:

“Actually, says Blakeslee, the reason most hurricanes don't have lightning is understood. "They're missing a key ingredient: vertical winds."

Within thunderclouds, vertical winds cause ice crystals and water droplets (called "hydrometeors") to bump together. This "rubbing" causes the hydrometeors to become charged. Think of rubbing your socked feet across wool carpet--zap! It's the same principle. For reasons not fully understood, positive electric charge accumulates on smaller particles while negative charge clings to the larger ones. Winds and gravity separate the charged hydrometeors, producing an enormous electric field within the storm. This is the source of lightning.

A hurricane's winds are mostly horizontal, not vertical. So the vertical churning that leads to lightning doesn't normally happen.”

The same article also noted that the electric field above Emily, as recorded by instruments on NASA’s ER-2 (U-2), were about 8 kilovolts/meter. Quite a strong field, indeed. They noted this was, indeed, an anomaly.


Link

Very Respectfully,

Jon

Since that, there have been publications linking lightning in eyewalls to intensification in the following 24(?) hours. There is a correlation to strengthening when lightning occurs in the eyewall.
Member Since: Posts: Comments:
Quoting Tazmanian:
ALEX is RIP it got in torn up by too march shear MX is safe

hahaha what the hell are u smoking taz
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Quoting TankHead93:
The 18Z NOGAPS has it slightly further south, just north of Puerto Rico heading towards the Bahamas.
Yup I saw it.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
2690:

That radar loops looks suspiciously like a category 4 or 5 hurricane.
Member Since: June 13, 2010 Posts: 0 Comments: 2336

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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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