Alex building an eyewall, still not a hurricane

By: Dr. Jeff Masters , 7:34 PM GMT on June 29, 2010

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Tropical Storm Alex is slowly building an eyewall, which is now more than 50% complete, according to recent satellite imagery and microwave images (Figure 1.) Satellite loops show a slot of dry air is spiraling into the center of the storm, and until this dry slot gets closed off, Alex will not be able to intensify significantly. Alex's heavy thunderstorms and low level spiral bands continue to slowly increase, but upper-level outflow is mediocre to the north and east, and absent elsewhere. The Hurricane Hunters are in the storm and have not found any hurricane-force winds at the surface yet.


Figure 1. Microwave "radar in space" image taken at 10:11 am CDT Tuesday June 28, 2010, showing that Alex had built an eyewall a little more than 50% complete. Image credit: Navy Research Lab.

Impacts
Alex is already 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. Since Alex is a large storm, it will have a storm surge that will affect most of the South Texas coast. 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 coast (Figure 2.) However, Alex is now unlikely to get that strong, and the surge should be less. Flooding damage from the expected 6 - 12 inches of rain from Alex will also be a major concern, as will wind damage. The combined wind, surge, and flooding damage from 2008's Hurricane Dolly, which hit near Brownsville, were about $1.05 billion. Dolly was a Category 2 hurricane offshore that weakened to a Category 1 hurricane with 85 mph winds when it made landfall. I expect Alex will be similar in its impacts to Dolly, though Alex's storm surge damage is likely to be greater. If Alex hits more than 50 miles south of the Texas border, as currently appears likely, the damage will be far less, since this region of the coast is relatively sparsely populated.


Figure 2. Maximum Water Depth (storm tide minus the elevation of the land it is passing over) computed using the primary computer model used by the National Hurricane Center (NHC) to forecast storm surge--the Sea, Lake, and Overland Surge from Hurricanes (SLOSH) model. The accuracy of the SLOSH model is advertised as plus or minus 20%. The "Maximum Water Depth" image shows the water depth at each grid cell of the SLOSH domain. Thus, if you are inland at an elevation of five feet above mean sea level, and the combined storm surge and tide (the "storm tide") is ten feet at your location, the water depth image will show five feet of inundation. This Maximum of the "Maximum Envelope of Waters" (MOM) image was generated for high tide, and thus shows the worst-case inundation scenarios for a mid-strength Category 2 hurricane moving WNW at 5 mph. For more information on storm surge, consult our detailed storm surge pages.

Track forecast for Alex
The latest 12 UTC (7am CDT) runs of our most reliable computer models confirm the faster movement of Alex to the coast, and residents in the affected areas now have 12 hours less to prepare for Alex's arrival than it seemed with yesterday's forecasts. Conditions will begin to deteriorate along the coast late tonight, so today is the day to finish preparations if you live near the Texas/Mexico border! The ridge that is steering Alex to the northwest is expected to strengthen today and Wednesday, which should push Alex on a more west-northwest and then westerly track on Wednesday. A few models even have Alex moving west-southwest by the time it makes landfall. The most northerly landfall location, near Brownsville, is predicted by the HWRF model.

To get the probability of receiving tropical storm force winds or hurricane force winds for your location, I recommend the NHC wind probability forecasts. The 4am CDT (9 UTC) wind probability product predicted that Brownsville, Texas had the highest odds of getting a direct hit from Alex:

Brownsville, TX: 88% chance of tropical storm conditions (winds 39+ mph), 23% chance of hurricane force winds (74+ mph). This is the cumulative probability through Saturday morning. The wind probability forecasts also include separate probabilities for each 12-hour period between now and three days from now, and each 24 hours for the period 4 - 5 days from now.

Corpus Christi, TX: 42% tropical storm, 1% hurricane.

La Pesco, MX: 37% tropical storm, 3% hurricane.

Freeport, TX: 18% tropical storm, 0% hurricane.

Tampico, MX: 14% tropical storm, 0% hurricane.

Galveston, TX: 13% tropical storm, 0% hurricane.

Intensity forecast for Alex
Alex is over a region of ocean with a warm, clockwise rotating Loop Current eddy that broke off from the Loop Current in July 2009 and moved west-southwest over the past 11 months. This eddy has 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, this afternoon and Wednesday. The combination of low wind shear and moderately high ocean heat content should allow Alex to intensify into a Category 1 hurricane, but time is running out for it to be a Category 2 hurricane. NHC is giving Alex a 79% chance of being a hurricane on Wednesday morning, and a 4% chance it will be a major hurricane at that time. Water vapor satellite images show the amount of dry air over the western Gulf of Mexico has decreased over the past day, though as I noted above, the dry slot wrapping into Alex's core is currently keeping the storm from closing off an eyewall. Dry air may turn out to be an increasing detriment to Alex on Wednesday as the storm approaches land. Another factor limiting Alex's intensification may be that the atmosphere is more stable than usual right now--temperatures at 200 mb are a rather warm -50°C, and are expected to warm an additional 1 - 2 degrees by Wednesday. I don't expect Alex to stall out again, so slow motion leading to upwelling of cold water will probably not be a problem for Alex. The main issue limiting intensification will be the fact that Alex is so large, and it takes more time for a large storm to organize. Thus, I think Alex has only a 10% chance of intensifying into a major hurricane before landfall.

Elsewhere in the tropics
The last few runs of the NOGAPS model have been predicting the formation of a tropical disturbance off the coast of Nicaragua on Friday or Saturday that will move northwestward towards western Cuba. The GFS model, and the two models that use it for starting conditions, the GFDL and HWRF, are indicating the possibility that a weak extratropical storm may form along coastal Alabama this weekend. It is unlikely that such a storm would be over water long enough to transition to a tropical storm.

Wind and ocean current forecast for the BP oil disaster
It currently appears that Alex's winds will not directly affect the oil slick location. However, because Alex is such a deep low pressure region, strong southeast to south winds of 10 - 20 knots will blow over the oil slick region today through Thursday, according to the latest marine forecast from NOAA. The resulting currents should act to push oil to the west and northwest onto portions of the Louisiana, Mississippi, and Alabama coasts, according to the latest trajectory forecasts from NOAA and the State of Louisiana. Oil will also move westward along the central Louisiana coast towards the Texas border. Alex is currently bringing swells of 3 - 4 feet to the coastal regions impacted by the oil slick, and these swells will increase to 6 - 8 feet on Wednesday. Wave heights will increase to 5 - 7 feet on Wednesday. Alex is expected to bring a storm surge of 1 - 2 feet along the coast in the oil spill region. The swells and waves that will accompany these high water levels will act to push oil deep into the marshlands in some locations. The long range forecast for the oil slick region is uncertain, due to the possibility a weak area of low pressure might develop late this week along the remains of a cold front draped across the region.

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

"Hurricane Haven" airing again this afternoon
Tune into another airing of my live Internet radio show, "Hurricane Haven", at 4pm EDT today. Listeners will be able to call in and ask questions. The call in number is 415-983-2634, or you can post a question in the comments area on my blog during the show. You can also email the questions to me today before the show: jmasters@wunderground.com. Be sure to include "Hurricane Haven question" in the subject line. Some topics I'll cover today on the show:

1) Alex
2) A look ahead at what may happen the rest of hurricane season

Today's show will be about 45 minutes, and you can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml. The show will be recorded and stored as a podcast.

Next post
I'll have an update Wednesday morning by 9:30am CDT. Rob Carver is planning on doing a late-night update tonight.

Jeff Masters

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Cantore in SPI... oh great, what is he looking to do? Catch a wave? I saw him in Melbourne Beach, FL back in 1999, covering Hurricane Floyd (which never hit us), with surfboard between live shots.
Member Since: March 19, 2010 Posts: 0 Comments: 1147
Hello,

Hurricane Alez try to build an eye, and finally goes to municipio of San Fernando Tamaulipas.


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GFS hasn't been great with Alex, but this is what some of the others are talking about on the GFS model for Friday (850MB)

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Quoting Tazmanian:
not heading for Mexico its heading for S TX/MX


Taz. Let's look at the facts. Alex is moving due west, and is at 22N. You still think it's a Texas/Mexico borderline??
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Quoting Snowlover123:


Lol, yeah. Heading due west it seems...

Brownesville probably won't even get much
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re 775

"Even a blind hog finds an acorn now and again" said Grandpa. "I'll just keep it around till it's fat." Only pig I know of died of old age.
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not heading for Mexico its heading for S TX/MX
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
Quoting 757weather:
Alex looks to be destined for Mexico


Lol, yeah. Heading due west it seems...
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Quoting atmoaggie:
LMAO. Was resisting that, myself.

Hi Atmo. As a former English teacher, I use restraint an infinitestimal amount of the time.
Finally, one slips out.
Not a literacy blog, so live with it.
Blame it on the Hubble.
Hubble's 20th anniversary image shows a mountain of dust and gas rising in the Carina Nebula. The top of a three-light-year tall pillar of cool hydrogen is being worn away by the radiation of nearby stars, while stars within the pillar unleash jets of gas that stream from the peaks.

Let us be thankful for small favors.
Alex is not as yet a killer storm.
Member Since: July 11, 2006 Posts: 14 Comments: 11424
Alex looks to be destined for Mexico
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Good evening.

Jim Cantore now in South Padre Island.
Member Since: August 9, 2009 Posts: 10 Comments: 5085
Quoting nocaneindy:


Lumping the rest of us in with one idiot? Typical!


Im not getting sucked into this
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Quoting HurricaneKatrina:
Alex looks like a cinnamon role!


I know, I was getting hungry just looking at it.
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Quoting Chicklit:
role - the part an actor plays.
roll - may be eaten or you can fall down and do.
LMAO. Was resisting that, myself.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting mtyweatherfan90:
P.D. Does anyone knows how can I submit editted photos. Since I need to copy a url link to the image. Thanks in advance!
Not a police officer, but I think you need tinypic.com. Upload a pic, copy the url.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
role - the part an actor plays.
roll - may be eaten or you can fall down and do.
Member Since: July 11, 2006 Posts: 14 Comments: 11424
Quoting MiamiHurricanes09:
Be back in a bit...


oh please... why leave now? who needs food or sleep??
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Thunderstorms coming off africa


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Quoting CycloneUK:


So just because it doesn't hit the US your not bothered? Typical.


Lumping the rest of us in with one idiot? Typical!
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823. IKE
Quoting Snowlover123:


IKE, is this moving due west now?


Looks so to me.
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Quoting atmoaggie:
No one got 775?
I did
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Quoting stormy2008:
While the 'hype' sounds nice... chances are that Brownsville will be lucky to see a gust to 40 mph.

Let's check back after land-fall...


Brownsville and Port Isabel have both seen gusts just shy of tropical storm force already.
Member Since: August 22, 2008 Posts: 0 Comments: 488
I think Alex is starting to tight up and to fill in the cloud absent spaces. Might be at the brink of becoming a hurricane...

Link



P.D. Does anyone knows how can I submit editted photos. Since I need to copy a url link to the image. Thanks in advance!
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if this dos not be come a hurricane by time today is out am going too send crow too the nhc BBQ crow that is


all this is now the strongets TS evere with out being a hurricane
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
Quoting IKE:
Buoy 42055....at 22.1N and 94.2W....

Wind Direction (WDIR): W ( 260 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 25.3 kts
5-day plot - Wind Gust Wind Gust (GST): 31.1 kts
5-day plot - Wave Height Wave Height (WVHT): 8.2 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 6 sec
5-day plot - Average Period Average Period (APD): 5.7 sec
5-day plot - Mean Wave Direction Mean Wave Direction (MWD): NNW ( 330 deg true )
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.35 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): -0.03 in ( Falling )
5-day plot - Air Temperature Air Temperature (ATMP): 82.4 °F
5-day plot - Water Temperature Water Temperature (WTMP): 84.9 °F
5-day plot - Dew Point Dew Point (DEWP): 76.6 °F
5-day plot - Heat Index Heat Index (HEAT): 90.5 °F


IKE, is this moving due west now?
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817. IKE
Buoy 42055....at 22.1N and 94.2W....

Wind Direction (WDIR): W ( 260 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 25.3 kts
5-day plot - Wind Gust Wind Gust (GST): 31.1 kts
5-day plot - Wave Height Wave Height (WVHT): 8.2 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 6 sec
5-day plot - Average Period Average Period (APD): 5.7 sec
5-day plot - Mean Wave Direction Mean Wave Direction (MWD): NNW ( 330 deg true )
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.35 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): -0.03 in ( Falling )
5-day plot - Air Temperature Air Temperature (ATMP): 82.4 °F
5-day plot - Water Temperature Water Temperature (WTMP): 84.9 °F
5-day plot - Dew Point Dew Point (DEWP): 76.6 °F
5-day plot - Heat Index Heat Index (HEAT): 90.5 °F
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Quoting stormy2008:
This will be a non-event for the U.S... other than some squally weather.


So just because it doesn't hit the US your not bothered? Typical.
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Quoting gator23:
.


Good move deleting that LOL
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No one got 775?
Member Since: August 16, 2007 Posts: 6 Comments: 12463
While the 'hype' sounds nice... chances are that Brownsville will be lucky to see a gust to 40 mph.

Let's check back after land-fall...
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So, is Alex heading due west right now?
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Alex looks like a cinnamon role!
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Quoting stormy2008:
This will be a non-event for the U.S... other than some squally weather.
I hardly call TS force winds and possibly hurricane force winds in Brownsville, TX a non-event! And with a wobble here or there who knows?
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Quoting GTcooliebai:

Here's GFS on Fri. system looks to start off in the NE Gulf, something Levi was talking about earlier where he mentions the possibility of a trof split.

Link
GFS 18 Z run would be horrible for oil spill movements...onshore, somewhat strong winds for the entire NE gulf.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
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Quoting atmoaggie:

Okay, I was really in Nerdland.

They have a special place of their own? Probably a good place to shop for pencil protectors.
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What time is recon supposed to arrive in Alex?

I think we may have sub 980 pressures this time around.
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Quoting Tazmanian:
oh all you firefox fans firefox 4.0 beta 1 is out any one want a link


WU-mail me the link please Taz.
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Wow... Alex is really getting himself together this evening! Really has fought off most of that dry air near the CoC, and now has a solid CDO. I thought hurricane at 5pm and was wrong. But I do say hurricane at 8pm.
Member Since: March 19, 2010 Posts: 0 Comments: 1147
Quoting stormy2008:
This will be a non-event for the U.S... other than some squally weather.
It might bring some flooding rains to certain areas of the U.S. Hard to tell where the remnants of Alex end up though.
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Quoting Grothar:


Hope you meant Nederland. If not explains al lot!.LOL How are you atmo! Nailed this one, too.
Hehe. The locals really do call it Nerdland...I didn't got to high school there, or anything, but, yeah, relative to the surrounding area, was a bit nerd-ish. I suppose I can see why.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Be back in a bit...
Member Since: September 2, 2009 Posts: 130 Comments: 21194
..
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Quoting P451:


Is this what you want?




thanks
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
Quoting atmoaggie:
NAM initializes the first closed isobar off of Georgia and then south off of FL in the GS:


Here's GFS on Fri. system looks to start off in the NE Gulf, something Levi was talking about earlier where he mentions the possibility of a trof split.

Link
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Bog blow of convection in last frame (blue spot). And something tells me that area isn't done expanding.

Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting AstroHurricane001:


Things to beware this season:

Gulf Stream riders
Gulf of Mexico oilcanes
First storm of September
Any storm that kills the Bermuda high
Any storm that rounds the Bermuda high as a born-again Cape Verde storm

Also, three things I would not trust Bastardi with:

1. Life-or-death decisions
2. Exact landfall locations for tropical cyclones beyond 5 days
3. Any statements pertaining to GW

4. A Dentist
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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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