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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1143. EricSFL
Quoting Kristina40:
The one coming off of Africa @ Eric.


I'll take it but make sure it's weak. lol
Member Since: May 26, 2010 Posts: 0 Comments: 803
Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

...HEAVY RAIN EVENT POSSIBLE THROUGH FRIDAY NIGHT...

.DISCUSSION...
A COMPLEX WEATHER PATTERN IS EVOLVING OVER SOUTHEAST TEXAS. DEEP
TROPICAL MOISTURE CONTINUES TO BE DRAWN INTO THE REGION. PARTS OF
THE REGION RECEIVED 6 TO 8 INCHES OF RAIN SO FAR TODAY. AT 19Z...A
WEAK SURFACE BOUNDARY WAS LOCATED ALONG A LCH TO BPT TO HOU TO
PSX LINE. THE BOUNDARY WILL GRADUALLY MOVE INLAND TONIGHT AND WILL
SERVE AS A FOCUS FOR ADDITIONAL SHOWERS AND THUNDERSTORMS. WITH PW
VALUES IN EXCESS OF 2.6 INCHES...MOISTURE AVAILABILITY IS NO
PROBLEM. DETERMINING WHERE MESO BOUNDARIES SET UP IS GOING TO BE
THE HEADACHE. GFS IS MORE AGGRESSIVE THAN THE NAM WITH MOISTURE
AND INSTABILITY. 4 KM WRF PROVIDES A BREAK IN THE PRECIP THIS
EVENING WITH ADDITIONAL HEAVY PRECIP ON FRIDAY. THE ECMWF HAS A
BROAD AREA OF RAIN BUT DOES NOT SHOW THE SURFACE BOUNDARY AS A
FOCUS. AN UPPER LEVEL RIDGE WHICH HELPED STEER ALEX INTO MEXICO
WILL SHIFT EAST OVERNIGHT AND ALLOW THE MOISTURE AXIS WHICH HAS
BEEN ORIENTED EAST-WEST TO PIVOT TO THE NORTH AND BECOME
ORIENTED NORTHWEST TO SOUTHEAST ALONG THE I-45/HWY 290 CORRIDOR.
FEEL BEST CHANCES FOR RAIN WILL OCCUR ALONG THIS AXIS LATE TONIGHT
INTO FRIDAY. AS FOR AMOUNTS...BEST GUESS IS AN ADDITIONAL 3 TO 5
INCHES OF RAIN WITH SOME ISOLATED 6 TO 8 INCH RAINFALL AMOUNTS.
AGREE WITH HPC`S QPFERD DISCUSSION. HAVE LEANED HEAVILY TOWARD THE
SREF MEAN MAX PRECIP FIELD FOR GUIDANCE ON THIS HEAVY RAIN EVENT.
THIS FLOOD WATCH MAY NEED TO BE EXPANDED INTO THE NORTHWEST ZONES
LATER THIS EVENING IF HEAVY RAIN BEGINS OVER THAT PART OF
SOUTHEAST TEXAS. THUS FAR...THE NW ZONES HAVE NOT RECEIVED MUCH IN
THE WAY OF HEAVY RAIN SO WILL HOLD THEM OUT OF THE WATCH FOR NOW.

DEEP MOISTURE WILL GRADUALLY LOWER OVER THE WEEKEND BUT WILL
REMAIN SUFFICIENT TO TRIGGER DIURNAL SHOWERS AND STORMS WITH
HEATING. DON`T THINK SAT-MON WILL BE A WASH-OUT BUT OUTDOOR
ACTIVITIES COULD BE INTERRUPTED BY A SHOWER. SLIGHTLY LOWER
HEIGHTS AND A CONTINUED TAP OF DEEP MOISTURE WILL KEEP RAIN
CHANCES IN THE FORECAST THROUGH MUCH OF NEXT WEEK. 43
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I am with you on that stormpetrol comment# 1122 and MiamiHurricanes09 comment# 1128.
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Quoting Baltimorebirds:
I'm bad with longitude and latitude which one is that.


Middle one.
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The one coming off of Africa @ Eric.
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01/1745 UTC 22.8N 101.1W OVERLAND ALEX -- East Pacific

Yay, we officially have nothing in the Atlantic. :)
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Quoting stayaway:
Someone just dumped the Gulf of Mexico on my house here in Houston


That can't be right because I thought the Gulf of Mexico was just dumped on MY house. :-)

Definitely a lot of water out there... not so much in northwest Harris County though. But down in southwest Houston it's a different story...
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1135. EricSFL
We need rain here in southeast FL. Humid and hot as heck, but no rain...
Member Since: May 26, 2010 Posts: 0 Comments: 803
Anyone wants some rain? I don't need it anymore!
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Quoting EricSFL:


Actually there is an intensity model called SHIPS. But I am not sure if the low pressure has to be designated an "invest" first for the model run to initialize.


Oh ok... i guess I'll have to wait
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hey all my fellow Caymanians looks like we are in for som rain that spin near us get you thinking but it seems to be an ULL making its way to the surface hmm well it will give us rain for the next few day
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Someone just dumped the Gulf of Mexico on my house here in Houston
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Quoting TexasHurricane:
Channel 12 - Beaumont,TX

A few feeder bands associated with Alex continue to affect Southeast Texas. New model data shows very heavy rainfall over Southeast Texas Friday. By the weekend, drier weather is expected with scattered showers and thunderstorms for Friday. Sunday looks mainly dry weather is expected with highs warming to near-ninety. Tuesday and Wednesday, a tropical wave will move into Southeast Texas which will enhance rainfall once again.

Long-range models show possible tropical development on the 9th in the Bay of Campeche with another storm moving into the Gulf of Mexico on the 11th.

I can't wait!
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The AOI's circled in red are the ones with the highest probability of development in the next coming days. With that being said, the area I'm mostly focused on is at approximately 10˚N 60˚W.

Member Since: September 2, 2009 Posts: 130 Comments: 21091
1127. EricSFL
Quoting kputerman26:

thank you. I thought that there was maybe another way or a model specifically for intensity


Actually there is an intensity model called SHIPS. But I am not sure if the low pressure has to be designated an "invest" first for the model run to initialize.
Member Since: May 26, 2010 Posts: 0 Comments: 803
Channel 12 - Beaumont,TX

A few feeder bands associated with Alex continue to affect Southeast Texas. New model data shows very heavy rainfall over Southeast Texas Friday. By the weekend, drier weather is expected with scattered showers and thunderstorms for Friday. Sunday looks mainly dry weather is expected with highs warming to near-ninety. Tuesday and Wednesday, a tropical wave will move into Southeast Texas which will enhance rainfall once again.

Long-range models show possible tropical development on the 9th in the Bay of Campeche with another storm moving into the Gulf of Mexico on the 11th.
Member Since: July 2, 2009 Posts: 0 Comments: 2811
We may not be out of it yet as there exists the possibility that Alex may "boomerang".

There exists a large area of low pressure which, as with Alex, earlier, has broken away from the equitorial belt and has gained strength as it heads for the narrows just to the south of the Yucatan Peninsula. Wave height and direction in the south eastern area of the Pacific are even now streaming south eastwardly and then north easterly as they approach the narrows. Alex, upon existing Mexico doesn't appear to have the strength left to resist this flow and may join the already established low headed for the narrows. Both are being influenced by a substantial area of high pressure located along the northern fifth of South America.

Currently, the Tropical Cyclone Heat Potential within the Gulf of Mexico, while not great, does exist. If it persists at its present strength, its influence could cause the linked lows to regenerate Alex to--perhaps--a Category 1 hurricane before it makes landfall near Corpus Christi within the next 3 to 5 days' time.

The forecasted wave height and direction conditions between Cuba and South America are likely to continue, as they have for the past 7 days, in an almost due west direction making the possibility of the re-formed hurricane moving east most unlikely.

Lastly, the north eastwardly wind shear will continue to strengthen as the TS southeast of Greenland continues to intensify. Its last known central pressure was 947 millibars as its southern edge passed over the mid and northern areas of the British Isles.
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Quoting EricSFL:


Look at the milibars in the models (measurement of atmospheric pressure) and then associate it with the corresponding winds.

thank you. I thought that there was maybe another way or a model specifically for intensity
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Quoting floridaT:
yes they should imo the new area of concern is just south of cuba lots a water vapor pouring in from the north

I see 3 AOI in my opinion , 1 , just south of Cuba, 2, just off the N coast of Panama, and 3 the area just south of the Windwards Islands. I think the area by the Windwards probably needs to watched, jmo.
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1121. EricSFL
Quoting kputerman26:


Are there any models or any way of telling the intensity of the low. If So I need to know for storms in the future.


Look at the milibars in the models (measurement of atmospheric pressure) and then associate it with the corresponding winds.
Member Since: May 26, 2010 Posts: 0 Comments: 803
Quoting Baltimorebirds:
Texas did need some rain though.
Yeah. After this though I think we're good. In this corner of the state anyway.
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Quoting StormW:


No...need a break during the day and off for the evening...I have 2 teen boys at home...on summer vacation, and a fiancee. Might modify things if we have a U.S. threat.
Oh ok. Hope everything goes well for you and yours.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting IKE:
I'm not saying the GFS is correct. New GFS did better with Alex, but the original GFS is consistent with a small low in the NE GOM. At 114 hours...



Are there any models or any way of telling the intensity of the low. If So I need to know for storms in the future.
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1117. EricSFL
Quoting Baltimorebirds:
Texas did need some rain though.


Northern Louisiana needs it the most.
Member Since: May 26, 2010 Posts: 0 Comments: 803
Quoting homelesswanderer:


Wow. Somebody opened Niagra Falls on my a..uh..It's raining really hard here. :) The gentle rains of yesterday are gone.


it rain kinda hard for a minute or two, now it is back to a light rain......
Member Since: July 2, 2009 Posts: 0 Comments: 2811
Wow, you sure can tell where those mountains are. Storms continue to fire right along their axis due to orographic forcing. Not looking good for them.....

Member Since: August 2, 2006 Posts: 46 Comments: 11665
1114. Ossqss
Quoting ShenValleyFlyFish:



Bolg: first appears in print June 11, 2010. Appears to to be a neologism deriving from the words Bog and Blog and referring to a site where posters cam become ensnared in meaningless posting.



I thought Bolg was in "Lord of the Rings" :)


Edit, Hummm, I seem to fit the definition quoted above with this post .......... L8R >>>
Member Since: June 12, 2005 Posts: 6 Comments: 8185
Quoting floridaT:
yes they should imo the new area of concern is just south of cuba lots a water vapor pouring in from the north

To be honest I only looked at the loop of Alex bit I'm gonna take a look now as I live in Grand Cayman in the Cayman Islands just south of that area.
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Quoting mtyweatherfan90:
Returning now that Internet works, pouring as hell for 36 hours straight. Parts of the city have received more than 60 cm of rain or more than 24 inches in 36 hrs.

Dang, that's almost 2 feet! Yeah, we're picking up your rain on the long-range Brownsville Radar. Hopefully, it should be almost done, but it's too far away from the radar to be sure.

Member Since: August 2, 2006 Posts: 46 Comments: 11665
Quoting TexasHurricane:


Hasn't seemed to rain much to me...maybe because it is in spurts...


Wow. Somebody opened Niagra Falls on my a..uh..It's raining really hard here. :) The gentle rains of yesterday are gone.
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1107. scott39
Quoting Dakster:
1 Storm down and how many to go???

1 Month down and 5 more to go.
An average of 4.5 a month for some forecasts!
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Quoting stormpetrol:

The NHC should be congratulated, they did an overall excellent job with Alex imo on everything, that's why they are the experts and we're just on the outside looking in, but its fun even as some one who just tracks storms and hurricane for enthusiasm to be totally wrong most of the time!
yes they should imo the new area of concern is just south of cuba lots a water vapor pouring in from the north
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Quoting stillwaiting:
surface obs now confirm a surface low pressure circulation near tallahasse,fl....


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Quoting EricSFL:


... and Texans, and Louisianians, and Mississippians too. LOL
Caymanians too. LOL Lots of different nationalities.
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Quoting floridaT:
good evening all has anyone looked at the weather at 21n 81w just south of cuba? looks like its trying to spin


Looks like it in this loop:

http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?joes_ir_central+12
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i see a little spin down by Costa Rica on visible. can anyone check it and tell me if I'm seeing it wrong? thanks in advance:)
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1099. Dakster
1 Storm down and how many to go???

1 Month down and 5 more to go.
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1097. EricSFL
Quoting Baltimorebirds:
So many people from the south.


'Cause we get hit by tropical cyclones the most.
Member Since: May 26, 2010 Posts: 0 Comments: 803
Quoting floridaT:
well i gotta admit as much as i doubted it the NHC was dead on balls acurrate with the Alex forecast. when it started to park in the boc i was sure it was going to go more north

The NHC should be congratulated, they did an overall excellent job with Alex imo on everything, that's why they are the experts and we're just on the outside looking in, but its fun even as some one who just tracks storms and hurricane for enthusiasm to be totally wrong most of the time!
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Quoting mtyweatherfan90:
Returning now that Internet works, pouring as hell for 36 hours straight. Parts of the city have received more than 60 cm of rain or more than 24 inches in 36 hrs.
holy webbed toes & water wings batman
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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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