Alex, strongest June hurricane in 44 years, is now a tropical storm

By: Dr. Jeff Masters , 2:20 PM GMT on July 01, 2010

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Hurricane Alex, the strongest June hurricane in 44 years, is Tropical Storm Alex, thanks to passage over the rugged terrain of Mexico. Alex made landfall at 9pm CDT last night, 110 miles south of Brownsville, Texas, as a Category 2 hurricane with 105 mph winds. Alex was the strongest June hurricane since Hurricane Alma of 1966, which had 125 mph winds as it skirted the west coast of Florida. Brownsville long-range radar shows that Alex's heavy rains continue to pound the Texas/Mexico border region, and satellite estimates of rainfall (Figure 1) show that some of Alex's spiral bands dumped rains in excess of five inches today, in addition to the 5+ inches that fell yesterday. The Brownsville airport received 6.46" of rain as of 8am CDT today from Alex. Alex is being blamed for at least thirteen deaths in Central America and Mexico due to flooding, though none of these deaths occurred in the region where the storm made landfall. Alex spawned two tornadoes that hit South Texas, and there were at least four other reports of tornado funnel clouds that did not touch ground. Alex may continue to spawn isolated tornadoes today over South Texas and northern Mexico.


Figure 1. Radar-estimated rainfall so far today for Alex.


Figure 2. Snapshot of the Brownsville long-range radar showing Hurricane Alex at landfall at 8pm CDT Wednesday June 30, 2010.


Figure 3. Alex nearing landfall in northeastern Mexico at 12:10 CDT June 30, 2010, as seen by the MODIS instrument on NASA's Terra satellite. Image credit: NASA.

Storm Surge
Alex's maximum storm surge occurred along a 50-mile stretch of the Mexican coast centered about 75 miles south of Brownsville, Texas. The National Hurricane Center Sea, Lake, and Overland Surge from Hurricanes (SLOSH) model predicted that the maximum water depth at the coast reached about 5 - 6 feet above ground level (Figure 3.) A storm surge of 1 - 2 feet was predicted by SLOSH for the Brownsville, Texas region. A storm surge of about 2 feet was observed in South Texas at the South Padre Island Coast Guard Station and Port Isabel.


Figure 4. Hurricane Alex's 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 surge occurred to the right of where Alex's core made landfall, over a sparsely populated marshy area. This "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. For more information on storm surge, consult our detailed storm surge pages.

Alex in historical context
Alex is the first June hurricane since Hurricane Allison of 1995. There have been only eleven hurricanes in May or June since 1945; only four of these were major Category 3 or higher storms.

Alex's bizarre behavior
Alex had several rather remarkable features I've never seen in a hurricane. Firstly, it underwent an eyewall replacement cycle as a Category 1 hurricane with 80 mph winds. Usually, we don't see the inner eyewall collapse and an eyewall replacement cycle occur until a hurricane reaches Category 3 strength. I've seen it happen on occasion to a Category 2 storm, but never a Category 1. Secondly, after Alex's inner 9-mile diameter eyewall collapsed at 10am EDT yesterday morning, an outer spiral band began to become the new eyewall. Winds in this outer spiral band/new eywall increased as the day progressed, as typically happens in an eyewall replacement cycle. However, part way through that process, Alex suddenly reversed course, and was able to build a small inner eyewall with a 12-mile diameter that was completed by landfall. I've never seen a hurricane change its mind in the middle of an eyewall replacement cycle and build an inner eyewall so fast. Finally, Alex had an unusually weak winds, considering how low the pressure was. The pressure was more typical of a hurricane one Saffir-Simpson category stronger than what the surface winds suggested.

Elsewhere in the tropics
The latest run of the NOGAPS model predicts the formation of a tropical depression the Western Caribbean on Tuesday. None of the other models is showing tropical development worthy of concern over the coming seven days.

Wind and ocean current forecast for the BP oil disaster
Alex is continuing to generate very rough conditions over the Deepwater Horizon blowout location, with 5 - 9 foot waves and 3 - 4 foot swells. The wind and seas will gradually subside today, according to the latest marine forecast from NOAA. The resulting currents induced by Alex's strong winds will push oil to many protected bays and estuaries that haven't seen oil yet. 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 5 - 15 knots Friday through Tuesday but remain mostly 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
I'll have an update Friday morning. Dr. Rob Carver plans on summarizing Alex in his blog later today.

Jeff Masters

Hurricane Alex (LRandyB)
Weather inbound to Hurricane Alex.
Hurricane Alex

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Quoting atmoaggie:
??? GFS develops an extra-trop syste min GOMEX tomorrow. And keeps it around for 5 days+. *Could* transition to tropical after being over warm waters that long.

Just sayin'. Tomorrow.


You seeing something I'm missing? Normally your on the ah conservative side of development.
Member Since: September 23, 2005 Posts: 14 Comments: 11029
Quoting StormSurgeon:
There is really not much out there now except a couple of model lows in the N. Gulf. Don't see it happening, and most of you will agree.
Link... Hey S.S- If you have time check the GEM.
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991. xcool
wave watch time hell yeah.
Member Since: September 26, 2009 Posts: 2 Comments: 15648
990. IKE
18Z GFS @ 18 hours shows a vorticity over the panhandle of Florida...

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Baltimorebirds:
Is that jfv?


Ain't me and you know it.......LOL
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Quoting CybrTeddy:
So this is what we're looking at.

ECMWF develops two systems, one in the BOC and one in the Caribbean by 192 hours out. (next Friday)

NOGAPS begins to develop a system 144 hours out in the Caribbean.

NAM develops a system in the GOMEX

CMC develops a system by 72 hours out in the GOMEX, makes it a fairly potent system too.

GFS appears to want to develop some sort of system in the GOMEX 168 hours out.


Could see 2 systems.


??? GFS develops an extra-trop syste min GOMEX tomorrow. And keeps it around for 5 days+. *Could* transition to tropical after being over warm waters that long.

Just sayin'. Tomorrow.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
986. IKE
Quoting StormW:
From my forecast this morning regarding what the models are seeing:

Given the current forecast pattern, I can't rule out at this time, with 500 mb heights forecast to rise over North America (NE), pressure falls to the south could yield a situational development anywhere from just west of the FL. west coast, to the Bahamas within the next 4-5 days.


Pretty good forecast.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
3 features to watch:

1. Trough over the panhandle of Florida (short term)

2. Disturbance around the Lesser Antilles (medium term)

3. Wave near 40W out in the Tropical Alantic (Medium-long term)
Member Since: October 28, 2006 Posts: 57 Comments: 30089
Quoting Baltimorebirds:
How many weeks are in july?5 or 6.So if a storm forms every week that's already 6 storms in the month of july.
6 weeks? You do understand that 6 weeks are 42 days, right? July features about 4.5 weeks, not 6.
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There is really not much out there now except a couple of model lows in the N. Gulf. Don't see it happening, and most of you will agree.
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Quoting Drakoen:
ECMWF 12z featuring and disturbance in the BOC and a disturbance in the central Caribbean



Nice tropical wave in the central Atlantic too.
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We've been getting dumped on by this system for two days now. I said the other night it felt like that "calm before the storm" that you get up in the Midwest before a Tornado.
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Quoting Drakoen:
ECMWF 12z featuring and disturbance in the BOC and a disturbance in the central Caribbean

Nevermind, saw it at 168hr.
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ECMWF 12z featuring and disturbance in the BOC and a disturbance in the central Caribbean

Member Since: October 28, 2006 Posts: 57 Comments: 30089
Quoting TankHead93:
Does ECMWF develop anything like some of the other models are showing?
Not much in the short-term.

ECMWF images
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Oops...
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Quoting TampaSpin:
Buckle up boys and girls......JULY and the first of August Is gonna be a rough one! Here it comes......OH BOY!



um ok. I will take your word for it. I have no idea what this is showing...
Member Since: July 2, 2009 Posts: 0 Comments: 2811
So this is what we're looking at.

ECMWF develops two systems, one in the BOC and one in the Caribbean by 192 hours out. (next Friday)

NOGAPS begins to develop a system 144 hours out in the Caribbean.

NAM develops a system in the GOMEX

CMC develops a system by 72 hours out in the GOMEX, makes it a fairly potent system too.

GFS appears to want to develop some sort of system in the GOMEX 168 hours out.


Could see 2 systems.


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And the low pressure center the NAM develops in the Western Caribbean is the same disturbance the ECMWF shows potential for in the NW Caribbean and BOC
Member Since: October 28, 2006 Posts: 57 Comments: 30089
are those waves out there by port of Spain and st. Georges? also by Costa Rica and Cuba looks kind of interesting. can someone tell me whats going on in those areas? thanks in advance:)
Member Since: September 10, 2008 Posts: 0 Comments: 1293
Kinda fuzzy :)

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12Z ECMWF 48 hour Ensemble Mean... lower pressure in the NE GOM.






Link
Member Since: September 23, 2005 Posts: 14 Comments: 11029
Quoting atmoaggie:
If you put this in front of me and said draw in isobars based solely on wind direction and velocity using only the marine observations, I'd put a "L ?" south of Pensacola...
(a weak, questionable low, but a low, nonetheless)






Hmmm I find this interesting, and funny, because the NWS has continuously bashed the GFS solution for developing "spurious" low pressure in the northern gulf, leading to torrential rain across Florida. Its weird that they haven't even considered it a possibly. Because it is the wet season after all around here, and sudden surges of extra rain that aren't predicted always pop up this time of year.

Also, with such an extremely moist air mass, a trough in place, and deep bursts of convection over the gulf, you would think they would at least consider the GFS for showing low pressure develop. Interestingly enough, the very location you pointed out is where the GFS insists a low pressure wave will organize the next couple of days.
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Buckle up boys and girls......JULY and the first of August Is gonna be a rough one! Here it comes......OH BOY!

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Quoting MiamiHurricanes09:
It did nothing less then magnificent with Alex so I'm starting to agree with you.
Does ECMWF develop anything like some of the other models are showing?
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Quoting Drakoen:


Maybe, Looks like we could see some GOM trouble later this week and then the potential for another Caribbean storm next week.


Let's just hope everything holds off until after the 4th so everybody can relax. Happy 4th all!
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It is not looking good in Mexico.
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Quoting Hurricanes101:


and at what coordinate and city block could this cause a problem and at what time of teh day sir bud sir?

Do I need to man my shower curtain?



Yes?
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Quoting Drakoen:


Starting to think we should just forget the other models and just use the ECMWF
It did nothing less then magnificent with Alex so I'm starting to agree with you.
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Quoting Baltimorebirds:
Like 08?


Maybe, Looks like we could see some GOM trouble later this week and then the potential for another Caribbean storm next week.
Member Since: October 28, 2006 Posts: 57 Comments: 30089
Quoting 1900hurricane:

Try this. Go to the top left and press the "year" button. Select 2005. Then you can select any storm you want from 2005 and view its imagery.
Thanks!
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Very colorful..

Member Since: July 2, 2009 Posts: 0 Comments: 2811
Quoting ElConando:


But what type of active Mr. Drakoen sir bud sir? Lightly active, moderately active, very active? Super active? COLOSSALLY ACTIVE?!?!? SHOWER CURTAIN ACTIVE?!?!?!?!?!


and at what coordinate and city block could this cause a problem and at what time of teh day sir bud sir?

Do I need to man my shower curtain?

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Quoting hydrus:
It could be a strong system too. Really warm water for it to feed on.
And it's supposed to hang around long enough that my wife'll need to shave by the time it moves off.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
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Quoting atmoaggie:

Like was said, June 24.

But, dang, that was a pretty good forecast!


Starting to think we should just forget the other models and just use the ECMWF
Member Since: October 28, 2006 Posts: 57 Comments: 30089
Quoting TankHead93:
Is anyone here in possession of pictures of invests and disturbances that became tropical depressions or more from the 2005 Hurricane Season?

Try this. Go to the top left and press the "year" button. Select 2005. Then you can select any storm you want from 2005 and view its imagery.
Member Since: August 2, 2006 Posts: 46 Comments: 11666
Quoting Drakoen:
Looks like an active July is ahead


But what type of active Mr. Drakoen sir bud sir? Lightly active, moderately active, very active? Super active? COLOSSALLY ACTIVE?!?!? SHOWER CURTAIN ACTIVE?!?!?!?!?!
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Link..GEM model shows three lows... One small low N.E. Gulf... One large low moving into Nicaragua... One large low S.E. of Bermuda....There is a fourth low off the East coast of FL.
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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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