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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1043. EricSFL
10:08 PM GMT on July 01, 2010
Quoting Baltimorebirds:
I might just move down their when I get older.However the only thing holding me back is the hurricanes.


I actually enjoy the beautiful weather during winter here in S FL. But trust me, one is better off fighting the cold than fighting heat!
Member Since: May 26, 2010 Posts: 0 Comments: 803
1041. scott39
10:07 PM GMT on July 01, 2010
Rain makes corn and corn makes whiskey!
Member Since: June 13, 2009 Posts: 0 Comments: 6732
1040. TXnovice
10:07 PM GMT on July 01, 2010
Quoting txalwaysprepared:


Just about...
I'm in the pretty hot pink color. 5 inches of rain (from my gauge) in the last 24 hours and counting. It's still pouring outside.


Where are you? I'm in Pearland. I don't know how much it has rained, but it's been steady most of the afternoon.
Member Since: August 29, 2008 Posts: 0 Comments: 80
1039. Drakoen
10:06 PM GMT on July 01, 2010
Quoting ShenValleyFlyFish:


WTW is a shwoing? Some Yiddish word I missed picking up when I was in NYC?


WTW is bolg? Maybe of the same origin as shwoing?
Member Since: October 28, 2006 Posts: 57 Comments: 29888
1037. StormSurgeon
10:05 PM GMT on July 01, 2010
You know, the GFS and GFC are pulling a small low to the N. Gulf coast in 2 days. What do you think?
Member Since: September 1, 2007 Posts: 0 Comments: 1793
1034. Drakoen
10:02 PM GMT on July 01, 2010
All I see is a big baroclinic mess draped across the northern GOM.
Member Since: October 28, 2006 Posts: 57 Comments: 29888
1033. txalwaysprepared
10:01 PM GMT on July 01, 2010
Quoting homelesswanderer:


Hey Tex. You floated away yet? This is nuts.



Just about...
I'm in the pretty hot pink color. 5 inches of rain (from my gauge) in the last 24 hours and counting. It's still pouring outside.
Member Since: August 18, 2007 Posts: 0 Comments: 1642
1032. EricSFL
10:00 PM GMT on July 01, 2010
Quoting Baltimorebirds:
Well you know what I mean cold.


That's because you don't live in S Florida. The heat and humidity are oppressive.
Member Since: May 26, 2010 Posts: 0 Comments: 803
1031. xcool
10:00 PM GMT on July 01, 2010


cool
Member Since: September 26, 2009 Posts: 2 Comments: 15620
1029. Ossqss
10:00 PM GMT on July 01, 2010
A few of the discussions today on other sites put up chances for the BOC, NE GOM, and C Caribbean. Some as early as next Tuesday. I didn't writum, just readum :)
Member Since: June 12, 2005 Posts: 6 Comments: 8185
1028. Drakoen
9:59 PM GMT on July 01, 2010
Looks like an inverted trough out to 42 hours on the GFS para 18z
Member Since: October 28, 2006 Posts: 57 Comments: 29888
1026. ShenValleyFlyFish
9:59 PM GMT on July 01, 2010
Quoting Drakoen:
If and when the GFS parallel starts shwoing development in the GOM is when I wil take more interest. The parallel version did a better job forecasting Alex.


WTW is a shwoing? Some Yiddish word I missed picking up when I was in NYC?
Member Since: September 9, 2007 Posts: 36 Comments: 4687
1025. homelesswanderer
9:58 PM GMT on July 01, 2010
Quoting TexasHurricane:
Very colorful..



Hey Tex. You floated away yet? This is nuts.

Member Since: August 15, 2008 Posts: 10 Comments: 3665
1024. hydrus
9:57 PM GMT on July 01, 2010
Quoting StormSurgeon:
Hydrus, I think the models are a bunch of nonsense for the moment, don't you? Let's see what develops over the next week....agreed?
Absolutely.
Member Since: September 27, 2007 Posts: 1 Comments: 20507
1022. atmoaggie
9:57 PM GMT on July 01, 2010
Well out in open water, SE of Pensacola.

Where did W and SW winds come from?


10 knots of late, mostly, not calm/variable.

No deep convection and rainfall in the right direction to blame it on.


All of the tall cloud tops are actually to the east of the ob.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
1021. StormSurgeon
9:55 PM GMT on July 01, 2010
Hydrus, I think the models are a bunch of nonsense for the moment, don't you? Let's see what develops over the next week....agreed?
Member Since: September 1, 2007 Posts: 0 Comments: 1793
1019. nrtiwlnvragn
9:55 PM GMT on July 01, 2010
Quoting atmoaggie:

For tropical transition? No. Just that 5 days is a long time for a low to just hang around in warm waters..."I'll take shear for a $1000, Alex"

For a low right here? *points SE* Man, tough to say it has less than half a chance with GFS insisting on it for the last 3 days, NAM and CMC coming aboard the bandwagon. And your ECMWF ensemble mean SD lends a little weight, too.


Ok, also FIM and COAMPS show a little also.
Member Since: September 23, 2005 Posts: 14 Comments: 10876
1017. sailingallover
9:53 PM GMT on July 01, 2010
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.



Lots of falling stars.......for now anyway..
Member Since: September 1, 2009 Posts: 23 Comments: 1007
1015. atmoaggie
9:53 PM GMT on July 01, 2010
Quoting Drakoen:
If and when the GFS parallel starts shwoing development in the GOM is when I wil take more interest. The parallel version did a better job forecasting Alex.

Is showing it now. But drifting off the west faster than the operational version.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
1014. mobilebayal
9:53 PM GMT on July 01, 2010
GEM
Link
Member Since: August 17, 2007 Posts: 0 Comments: 1098
1013. Drakoen
9:52 PM GMT on July 01, 2010
GFS parallel 12z develops a BOC system like that ECMWF that moves into Mexico:

Member Since: October 28, 2006 Posts: 57 Comments: 29888
1012. atmoaggie
9:52 PM GMT on July 01, 2010
Quoting nrtiwlnvragn:


You seeing something I'm missing? Normally your on the ah conservative side of development.

For tropical transition? No. Just that 5 days is a long time for a low to just hang around in warm waters..."I'll take shear for a $1000, Alex"

For a low right here? *points SE* Man, tough to say it has less than half a chance with GFS insisting on it for the last 3 days, NAM and CMC coming aboard the bandwagon. And your ECMWF ensemble mean SD lends a little weight, too.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
1011. Grothar
9:52 PM GMT on July 01, 2010
Quoting MiamiHurricanes09:
6 weeks? You do understand that 6 weeks are 42 days, right? July features about 4.5 weeks, not 6.


What's the matter 09, never read "The Long, Hot Summer"??
Member Since: July 17, 2009 Posts: 69 Comments: 25369
1009. StormSurgeon
9:51 PM GMT on July 01, 2010
Where?
Member Since: September 1, 2007 Posts: 0 Comments: 1793
1008. hydrus
9:50 PM GMT on July 01, 2010
Quoting StormSurgeon:


Lots of Rossbys, what else do you see?
.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. Look closely at the for the low off the east coast of Fl.
Member Since: September 27, 2007 Posts: 1 Comments: 20507
1004. Grothar
9:48 PM GMT on July 01, 2010
Persistant thing, this Alex! Is this image old, or is that blob still going?

Member Since: July 17, 2009 Posts: 69 Comments: 25369
1001. Drakoen
9:46 PM GMT on July 01, 2010
If and when the GFS parallel starts shwoing development in the GOM is when I wil take more interest. The parallel version did a better job forecasting Alex.
Member Since: October 28, 2006 Posts: 57 Comments: 29888
1000. xcool
Baltimorebirds haha true.
Member Since: September 26, 2009 Posts: 2 Comments: 15620
Quoting hydrus:
Link... Hey S.S- If you have time check the GEM.


Lots of Rossbys, what else do you see?
Member Since: September 1, 2007 Posts: 0 Comments: 1793
Quoting Jedkins01:





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.

NWS SLidell (for NOLA/BR) says:

THE SURFACE BOUNDARY OVER THE REGION WILL BE THE FOCUS FOR
CONVECTION FOR THE NEXT 24 TO 36 HOURS. A GOOD DEAL OF UNCERTAINTY
IN THE FORECAST WITH A WIDE RANGE OF SOLUTIONS FOR THE
AFOREMENTIONED BOUNDARY...THE GFS BEING THE MOST AGRESSIVE. WILL
BASE FORECAST ON THE DEVELOPMENT OF A NON TROPICAL LOW ALONG THE
BOUNDARY WHICH RETROGRADES ACROSS THE GULF COAST REGION.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
996. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15620
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.
About your forecast, I was reading it a little earlier and I was wondering if you were still going to be blogging on this blog outside of operational hours?
Member Since: Posts: Comments:
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: 10876

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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.