Alex Slowly Gains Strength

By: Dr. Jeff Masters , 6:35 AM GMT on June 29, 2010

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Hello, it's Dr. Rob Carver substituting for Jeff on the late shift.

As of the 0100 EDT advisory, Alex is 475 miles SE of Brownsville TX moving NNW at 8 mph. The advisory wind speed is 65 mph with a minimum central pressure of 985 mb. The most recent vortex fix was at 1225EDT with an unchanged pressure reading. Alex is expected to take a turn to the NW and make landfall just south of Brownsville late Wednesday night/early Thursday morning. The government of Mexico has issued a hurricane warning from the mouth of the Rio Grande south to La Cruz. NHC has hoisted the hurricane warning flag from the Rio Grande north to Baffin Bay. A tropical storm warning extends from Baffin Bay to Port O'Connor. Alex is expected to expand in size so it will be much larger than Hurricane Dolly, which was the last storm to affect the region in 2008.

Hurricane Local Statements are now being issued by the Brownsville and Corpus Christi NWS offices. These statements provide a detailed look at how Alex will affect the region and summarize how local emergency management is responding to the situation.

Alex has three different ways to negatively impact the Rio Grande Valley: storm surge, heavy rains, and strong winds.

Risk of Storm Surge
NHC is forecasting a storm surge of 3-5 feet along the coast north of where Alex makes landfall. The exact details of the surge's extent depend on where Alex makes landfall and how big it gets while it is over the open water. I've include a plot of the statistical storm surge forecast product. Unless Alex refuses to make it's left turn, I don't think there's a chance of storm surge north of Port O'Connor.

Plot of experimental storm surge forecast.

Threat from Rain
NHC thinks 5 to 10 inches of rain over southern Texas/northern Mexico is possible when Alex makes landfall. This is why the Brownsville office thinks the primary threat from Alex will be inland flooding in areas with poor drainage.

Alex has a history of producing torrential amounts of rain as shown by this estimate of rainfall during Alex's passage over the Yucatan Peninsula.

Satellite-derived rainfall estimates for June 27, 2010 using data from the Climate Prediction Center.

Threat from Wind
Alex is currently forecast to reach hurricane status. There will likely be hurricane force winds along the coast where Alex makes landfall. The current hurricane wind probabilities show that Brownsville has a 77% chance of experiencing tropical storm force winds and a 18% chance of experiencing hurricane force winds. Corpus Christi has a 44 % chance of tropical storm winds and a 4% chance of hurricane force winds. There is also the possibility of tornadoes forming in outer rainbands as Alex makes landfall.

The Curious Incident of the Hurricane Dynamical Models
One thing that strikes me as odd about Alex is that neither the GFDL nor the HWRF have been intensifying the storm into a hurricane in the past few model runs. This is intriguing because Alex is already a strong tropical storm. It will bear watching to see if GFDL/HWRF continue this pattern for future storms.

Next Update
Jeff will post an entry sometime this morning, and I'll have another entry late Tuesday night.

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Good Morning from hot and humid Buda Texas
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110. redux
I am a novice at this....

is that subtropican ridge a sure thing to develop?

from a statistical standpoint, you would think at least one of the runs of the model would show it not developing.
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108. IKE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
533 AM EDT TUE JUN 29 2010


.SHORT TERM (TODAY-THURSDAY)...
DEEP SOUTHERLY FLOW AROUND THE SUBTROPICAL RIDGE AXIS WILL ALLOW
PLENTY OF DEEP LAYER MOISTURE FROM TS ALEX IN THE SOUTHWESTERN GULF
TO CONTINUE STREAMING NORTH OVER THE REGION THROUGH THE MID-WEEK
PERIOD. NHC`S LATEST FORECAST TRACK KEEPS ALEX ON A GENERAL NW TRACK
AND MAKING LANDFALL JUST SOUTH OF THE TX/MEX BORDER LATE WEDNESDAY
NIGHT AFTER MIDNIGHT. THE VERY WEAK STEERING CURRENT BETWEEN 850-500
MB AROUND ALEX IS THE REASON FOR THIS SLOW FORECAST TRACK OVER THE
SWRN GULF. IN ADDITION TO THE ENHANCED TROPICAL MOISTURE...A FRONTAL
BOUNDARY ASSOCIATED WITH AN UPPER TROUGH CURRENTLY ORIENTED FROM THE
GREAT LAKES REGION TO THE MIDWEST WILL APPROACH OUR LOCAL AREA LATE
WEDNESDAY NIGHT THROUGH THURSDAY.

ALTHOUGH QUITE A BIT OF DIFFERENCES ARE NOTED BETWEEN THE VARIOUS
MODEL SOLUTIONS IN THIS FORECAST PACKAGE...ESPECIALLY COME THURSDAY
AND BEYOND AS A FEW OF THE MODELS SPIN UP A SURFACE LOW OVER OUR
AREA ALONG OR AHEAD OF THE FRONTAL BOUNDARY...A GENERAL WET AND
UNSETTLED PATTERN CAN BE EXPECTED. PROVIDED THESE UNCERTAINTIES...WE
WILL CONTINUE TO ADVERTISE WELL ABOVE AVERAGE RAINFALL PROBABILITIES
IN THE FORECAST. THE MODELS CONTINUE ADVERTISE LARGE RAINFALL
ACCUMULATIONS ACROSS THE CWA WITH THE HIGHEST ACCUMULATIONS
REMAINING CLOSER TO THE GULF COAST AND THE LOWER VALUES OVER
SOUTHEAST AL AND SRN GEORGIA. THESE VERY HIGH ACCUMULATIONS ARE
LIKELY DUE TO THE SURFACE LOW BEING SPUN UP OVER THE LOCAL AREA
THROUGH THE DAY THURSDAY...WHICH SEEMS TO BE OVERDONE AT THIS TIME.

THE LATEST ECMWF SEEMS TO OFFER THE MOST REASONABLE SOLUTION AND
ONLY SHOWS THE PREVIOUSLY MENTIONED FRONTAL BOUNDARY SHIFTING SOUTH
OVER THE CWA BY THE END OF THE SHORT-TERM PERIOD. WILL KEEP THE QPF
WELL BELOW THESE MODEL SOLUTIONS AT THIS TIME CONTINUE TO MONITOR
THE LATEST GUIDANCE.


.LONG TERM...(FRIDAY THROUGH TUESDAY)...WITH THE OFFICIAL FORECAST
FROM THE NATIONAL HURRICANE CENTER TAKING ALEX INLAND WELL OFF TO
OUR SOUTHWEST SOMETIME ON THURSDAY...POPS WILL LIKELY BE THE
GREATEST CHALLENGE IN THE EXTENDED FCST. ALTHOUGH THE TRACK AND
TIMING OF ALEX IS SUBJECT TO CHANGE...UNLESS THERE IS A VERY
SIGNIFICANT DIFFERENCE IN ITS FINAL TRACK...FRIDAY SHOULD BE ONE OF
THE WETTEST DAYS ACROSS THE CWA DURING THIS PERIOD. THIS WILL BE DUE
TO AMPLE MOISTURE ADVECTING IN FROM THE GULF OF MEXICO BETWEEN ALEX
WELL TO THE SW AND THE APPROACHING WEAK COLD FRONTAL BOUNDARY TO THE
NORTH. THE REMAINDER OF THE PERIOD WILL BE MUCH MORE DIFFICULT TO
PROJECT...AND WILL DEPEND ON HOW MUCH DRY AIR ENTRAINS INTO THE
REGION BEHIND THE COLD FRONT...AND HOW MUCH...IF ANY RESIDUAL
MOISTURE FROM THE REMNANTS OF ALEX HEADS BACK NE TOWARDS THE SE
U.S.. THE NEW 00 UTC RUN OF THE GFS IS IN...AND IT LOOKS LIKE A BIG
OUTLIER COMPARED TO THE OTHER GLOBAL MODELS...AS IT DEVELOPS A NEW
WAVE OF LOW PRESSURE ON THE TAIL END OF THE COLD FRONT AND STALLS IT
JUST TO OUR WEST.
THIS PATTERN WOULD ACTUALLY INCREASE THE MOISTURE
INFLUX FROM THE GULF OF MEXICO AND KEEP US EXTREMELY WET THROUGH THE
ENTIRE PERIOD. THEREFORE...WILL LEAN HEAVILY TOWARDS THE DRIER ECMWF
SOLUTION...
BUT WILL STILL ACCOUNT FOR THE USUAL AFTERNOON AND
EVENING SEA BREEZE INDUCED SHOWERS AND THUNDERSTORMS.
.......


6Z GFS @ 84 hours still spins up a northern GOM low....

Member Since: June 9, 2005 Posts: 23 Comments: 37860
Many Thanks for update DR. Carver, good job.
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Matamoras is heavily populated. Track seems to have it in the bullseye now.
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Good Morning

Blog Update

Alex nearing hurricane strength
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Quoting IKE:
Two days left and it's inland in northern Mexico(about 75-100 miles south of the Texas state line).... Hope no one is injured....



Morning IKE, Yes youre right Critical zone could receive hurricane force winds between Tampico and Matamoros Border
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101. IKE
Two days left and it's inland in northern Mexico(about 75-100 miles south of the Texas state line).... Hope no one is injured....

Member Since: June 9, 2005 Posts: 23 Comments: 37860
It's been hot here to but the past feww days it's been nice with a nice wind blowing
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GFS 06Z 42 hours Finally land Storm at north of Mexico
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Oh good I got my Picture up now. lol
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Quoting 34chip:
Sorry it's hot there natrwalkn


should get a little cooler tomorrow. local met said this has been our hottest june on record!
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Sorry it's hot there natrwalkn
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GFS 6Z 12h
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wow low
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Goodnight, Levi32
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Great forecast by Stewart....as every one of his has been so far on this storm. Great reasoning on the models possibly being still a bit too far south based on Alex's behavior and cloud pattern.

I'm out as well, till tomorrow everyone.
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Feeder bands on Brownsville long range
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12pm eye
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HAS SHIFTED
SOUTHWARD. HOWEVER...ALEX HAS SHOWN NO SIGNS OF MAKING ANY
SIGNIFICANT WESTWARD PROGRESS LIKE THE ECMWF...NOGAPS...GFS...AND
GFDL MODELS HAVE BEEN AND ARE STILL FORECASTING TO OCCUR. THE
MODELS ARE CONSISTENT...HOWEVER...ON BUILDING A SUBTROPICAL RIDGE
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Well I'm off to bed, night everyone!
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ON BUILDING A SUBTROPICAL RIDGE
TO THE NORTH AND EAST OF ALEX OVER THE NEXT 3 DAYS...WHICH IS

wt---
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There is an eye so hurricane at 11am i think or 5
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Quoting 34chip:
Hi natrwalkn How are ya? Am in Key West weather is great here.


Greensboro, NC and it's hot as fire here.
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DEEP CONVECTION IN THE EASTERN SEMICIRCLE OF THE
SMALL DEVELOPING EYE HAS ALSO INCREASED.

So there is actually an eye :O LOL
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need 5mph
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he move fast 10mph
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SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...21.7N 91.9W
ABOUT 405 MI...650 KM ESE OF LA PESCA MEXICO
ABOUT 460 MI...735 KM SE OF BROWNSVILLE TEXAS
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/HR
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 8 MPH...13 KM/HR
MINIMUM CENTRAL PRESSURE...984 MB...29.06 INCHES
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Outflow on N and NW side may be improving a little, but sat still looks very ragged.

Side note...I wonder if the big blob of energy to the north of Alex that seems to be displaced somewhat from the storm doesn't turn into the infamous "spurious vorticity maxima" in the GFS from a couple of days ago...
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It's funny how things change, the steering currents now show a stronger ridge.. I'm in full agreement with the NHC, borderline storm. I'll be making a new map tomorrow, track will be very close to the NHC track cause after looking at the steering maps, it should travel NNW for a few more hours, then the ridge builds to the north and steers Alex westward into Mexico or Texas. Depends how much more north Alex gets, it has moved a bit more faster over the past few hours. So I will wait till later to make the call.
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who say was ?
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alex is not coming to florida
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w/b rob
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Alex looks like he is going to be a ragged looking Cat1 if he doesn't get his act together soon. It has been having trouble on the W side getting wrapped around. Something is going on because the NHC said the shear was decreasing earlier. the only thing i can think of is that ULL to the NW. The GFDL may have been on to something with the intensity. Notice how the band to the N has not been able to wrap down to the W of Alex. If that piece of energy breaks off then the GFS gets a big nod for at least sniffing that out.
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odd, north wind here in Port Lavaca Texas.
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.
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:0
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Hi natrwalkn How are ya? Am in Key West weather is great here.
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62. jsit
its doing something wierd right now.... where is the real center of the thing? looks like its scooting around. Guess Im a newby at this sort of thing but I really cant tell. With that big old mass of what looks like storms above it- will it really matter where the center hits anyhow?
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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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