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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Quoting StormChaser81:


I just ignored him, its easier that way, dont have to even type.


Wait...you ignored Reed but you didn't Stormkat?
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Quoting Clearwater1:


???? this track has been up for the last two days. NHC


Do you even read the blog? Or just look to start things?


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.
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Hurricane Haven's on, open the stream and comment on here!
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Quoting CybrTeddy:
Alright, gotcha lol.
In fact, Alex has had much larger areas of much colder cloud tops since last night until about 2 hours ago. Lots of blues and white-beyond-blue in the color scheme in post 9. Just starting to show some blue again close to center.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
The Dr is in!! check out the podcast..

Link
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Live Galveston Wave Cam link

Link
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It would be interesting to see the hurricane kinetic energy plot for Alex seeing the size he is.

Anyone willing to indulge ;)?
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Well mtyweatherfan90 I think that that red area is what is known as the Hebert box
Link
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Quoting hurrkat05:
reedzone grow up man let it go you sound like a kid in a candy store...


I just ignored him, its easier that way, dont have to even type.
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Quoting reedzone:
WOW, the models may be spot on with the westward trend, looking at the visible loop, with the forecast points, clearly shows a strong wobble to the west. Probably a WNW motion, more then I thought. Just so you guys know, I never predicted Alex to go to LA, the most I had it going north was southern Texas, which was reasonable at the time. I never fought with anyone on here last night, in fact, I was barely blogging here. Last, I was not saying scottsvbs forecast was wrong, I just didn't like it when he said Alex WILL, instead of Alex might. There is no "will do" in a forecast because we can most likely be wrong. I wasn't bashing him on his forecast like he does with mine. I just wanted to clear that up with anybody who does not have me on ignore.

Seriously, let go of this!
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Quoting MrNatural:
What is going on with Alex?? The various water vapor loops I watch are showing that the SW redirection seems to be more than a little jog or wobble. Alex seems to be taking on a more SW component. I have also noticed that the north side of the storm is less concentric and flattening out a touch. Is anybody else seeing that?
Link


Look at that mimic, last frames. Alex half eyewall seems to be reformed a little to the southwest.
http://cimss.ssec.wisc.edu/tropic/real-time/marti/2010_01L/webManager/last24hrs.gif
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South Padre Cam Link...

Link
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Poor Alex doesn't get a break

Here is this amazing satellite presentation that he is displaying and still some are nitpicking about the smallest things wrong with him lol
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Quoting muddertracker:
Fantastic South Padre Island Web-Cam! Press play and watch the storm roll in. Neat live/satellite side by side screen.

Link


Do you have a different link? This one shows a storm from 2008.
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Quoting ssmate:
Dumb question alert: I know less about Texas than Goerge Costanza but I am wondering, does Brownsville have large expensive houses on/near the beach such as south FL or is it a more affordable place to live near the ocean. I wish no harm either way but am curious. Location wise it would appear a beautiful place to live, thus expensive.


Brownsville is a mix, like most seaside towns...
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Quoting mtyweatherfan90:
Orca, just curious. What does the warning red sign on your AOI maps implies? I know it represents danger but certainly like what type of conditions should I expect. You recently tagged me on your maps, thanks by the way! :)

That be your house :)
Member Since: October 1, 2007 Posts: 81 Comments: 26516
Quoting MrNatural:
What is going on with Alex?? The various water vapor loops I watch are showing that the SW redirection seems to be more than a little jog or wobble. Alex seems to be taking on a more SW component. I have also noticed that the north side of the storm is less concentric and flattening out a touch. Is anybody else seeing that?
Link


Your seeing shear at work and dry air ingestion.
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@55, funny!
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Quoting muddertracker:
Fantastic South Padre Island Web-Cam! Press play and watch the storm roll in. Neat live/satellite side by side screen.

Link


Umm, 2008 that was Dolly
Member Since: August 14, 2007 Posts: 0 Comments: 439
Brownsville is a bustling city of about 150,000 people. Nearby is resort area of South Padre Island. Not a huge population in S TX, but enough lives will be interrupted by this thing though.
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What is going on with Alex?? The various water vapor loops I watch are showing that the SW redirection seems to be more than a little jog or wobble. Alex seems to be taking on a more SW component. I have also noticed that the north side of the storm is less concentric and flattening out a touch. Is anybody else seeing that?
Link
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Alex sure is soaking us in Metairie right now. Local minor flooding.
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Quoting RCThunder:
Evacuation Cam showing cars getting out:
Link
That is the Port Aransas ferry line. Port A is across the bay from Corpus Christi, at least 150 miles North of the projected landfall. Just normal traffic.
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Quoting reedzone:
WOW, the models may be spot on with the westward trend, looking at the visible loop, with the forecast points, clearly shows a strong wobble to the west. Probably a WNW motion, more then I thought. Just so you guys know, I never predicted Alex to go to LA, the most I had it going north was southern Texas, which was reasonable at the time. I never fought with anyone on here last night, in fact, I was barely blogging here. Last, I was not saying scottsvbs forecast was wrong, I just didn't like it when he said Alex WILL, instead of Alex might. There is no "will do" in a forecast because we can most likely be wrong. I wasn't bashing him on his forecast like he does with mine. I just wanted to clear that up with anybody who does not have me on ignore.


I don't have anyone on ignore.....no harm done here.
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Hello St. Simons......


Alex is trucking now.... It may be ashore by this time tomorrow.... Hurricanes in the past have strengthen in 6 hours to major status. It can be done.
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Quoting Stormchaser2007:
Wow



Looks like a swiss cake roll... MMMMM
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Quoting GlobalWarming:


I concur.


Why?
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Quoting ssmate:
Dumb question alert: I know less about Texas than Goerge Costanza but I am wondering, does Brownsville have large expensive houses on/near the beach such as south FL or is it a more affordable place to live near the ocean. I wish no harm either way but am curious. Location wise it would appear a beautiful place to live, thus expensive.


Use google earth it will answer your question.
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WOW, the models may be spot on with the westward trend, looking at the visible loop, with the forecast points, clearly shows a strong wobble to the west. Probably a WNW motion, more then I thought. Just so you guys know, I never predicted Alex to go to LA, the most I had it going north was southern Texas, which was reasonable at the time. I never fought with anyone on here last night, in fact, I was barely blogging here. Last, I was not saying scottsvbs forecast was wrong, I just didn't like it when he said Alex WILL, instead of Alex might. There is no "will do" in a forecast because we can most likely be wrong. I wasn't bashing him on his forecast like he does with mine. I just wanted to clear that up with anybody who does not have me on ignore.
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Orca, just curious. What does the warning red sign on your AOI maps implies? I know it represents danger but certainly like what type of conditions should I expect. You recently tagged me on your maps, thanks by the way! :)
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Dumb question alert: I know less about Texas than Goerge Costanza but I am wondering, does Brownsville have large expensive houses on/near the beach such as south FL or is it a more affordable place to live near the ocean. I wish no harm either way but am curious. Location wise it would appear a beautiful place to live, thus expensive.
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You can still see shear working its magic, pushing the cloud tops to the southeast.
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AOI

AOI

AOI

Hurricane Hunter Data

TS BUSTED FORECAST ALIBI

More then a few people might want to start preparing their "TS BUSTED FORECAST ALIBI" :)
Member Since: October 1, 2007 Posts: 81 Comments: 26516
Quoting PcolaDan:


From experience I know it can be weird crossing into Mexico. Rules can change daily.


Now, imagine what the Mexican side guards will think in looking at what appears to be bomb squad protective gear...anyone know any good Mexican lawyers?
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Evacuation Cam showing cars getting out:
Link
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Quoting weatherboyfsu:
Im willing to bet that by tomorrow morning we will have a major hurricane on our hands. Mexico will have a major hurricane on their hands!!!!!!

Why not?

I must admit that when I saw the visible loop..... I got chills. Alex is should wink at us sometime tonight~


Really serious doubt it will become a major hurricane, you forget with bigger storms like Alex and Ike there a lot more storm to get going. The bigger you are the more it takes to get you going.
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Quoting Daveg:


Anyone got a good radar perspective from Brownsville?


Brownsville NEXRAD Loop
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I have a feeling we could see a burst of intensification tonight since Alex has dropped the dry air in the western quadrant.

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June 29, 2010............ A hurricane in the Gulf of Mexico.........

Sure making the prognosticators feel better......
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Quoting weatherboyfsu:
Im willing to bet that by tomorrow morning we will have a major hurricane on our hands.

Thats probably a litte soon. I would say tomorow night is the earliest we would see a major
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Alright, gotcha lol.
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Alex seems to be enjoying that warm water.
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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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