SE TX/SW LA weather: Much cooler and WET after Tuesday

[Ed Mahmoud]

Yup, I little thunder and lightning here. From the looks of radar about 7 pm, I figured we were worked over until early morning at the earliest.

[southerngale]

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1151 PM CDT FRI APR 17 2009

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHERN LIBERTY COUNTY IN SOUTHEAST TEXAS...

* UNTIL 1230 AM CDT

* AT 1151 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL. THIS
STORM WAS LOCATED NEAR DAYTON...AND MOVING NORTHEAST AT 20 MPH.

* LOCATIONS IN THE SEVERE THUNDERSTORM WARNING INCLUDE BUT ARE NOT
LIMITED TO LIBERTY...DAISETTA AND AMES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

[vbhoutex]

Definitely looks like we have an "unexpected" disturbance coming out of S TX continuing to generate these rains. It is still/once again raining here. I too thought we had been thoroughly worked over till tomorrow afternoon, but like Jason said, apparently there is a lot more instability with this system than some thought. I was thinking these continued rains would preclude any rounds of heavy later today, but now I am not so sure since that is supposed to be triggered by an ULL coming across TX. We shall see. We could be putting a huge dent in the rain deficits in the area before this is all over. Unfortunately that may include/already is including some flooding in some areas to the West of the Houston metro area.

[Ptarmigan]

I heard on TV that all those rain forming right now will recharge for tomorrow.

[southerngale]

I'm getting a lot of loud thunder rumblings now. That cell that spawned the severe thunderstorm warning in Liberty County is approaching my area now. So far, it still looks just as strong, but no warning yet, so hopefully just a spunky thunderstorm. It's getting loud and starting to rattle the windows a little. Mommy!

[HouTXmetro]

wierd southeast texas radar presentation tonight. The storms appear to be moving outward in a pattern similar to someone throwing a rock into a pond and you can see the waves moving outward. Anyone else notice?

http://radar.weather.gov/radar.php?rid= ... 1&loop=yes

edit: maybe it's just the circular radar coverage creating this appearance. After looking further, most storms appear to be moving from SW to NE.

[jasons2k]

I just checked the rain guage, and I had 2.45" in it. This is from yesterday and whatever else we had overnight. Looks like more is on the way soon - may not go the Crawfish Festival today after all - we might opt for tomorrow instead.

Radar:


Shot at 2009-04-18

These are the storm totals thus far. Radar shows a max of 13.4" (listed on the right).


Shot at 2009-04-18

[jasons2k]

FLOOD WATCH
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
430 AM CDT SAT APR 18 2009

...FLOOD WATCH REMAINS IN EFFECT THROUGH THIS EVENING...

THE FLOOD WATCH CONTINUES FOR

* A PORTION OF SOUTHEAST TEXAS...INCLUDING THE FOLLOWING
COUNTIES...AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...HOUSTON...
JACKSON...LIBERTY...MADISON...MATAGORDA...MONTGOMERY...POLK...
SAN JACINTO...TRINITY...WALKER...WALLER...WASHINGTON AND
WHARTON.

* THROUGH THIS EVENING

* ANOTHER ROUND OF STRONG THUNDERSTORMS IS EXPECTED TO AFFECT
SOUTHEAST TEXAS FROM LATE THIS MORNING THROUGH THIS EVENING AS
AN APPROACHING STORM SYSTEM COMBINES WITH A VERY MOIST AND
UNSTABLE AIRMASS IN PLACE OVER THE AREA. ADDITIONAL RAINFALL
TOTALS THROUGH THIS EVENING WILL AVERAGE 1 TO 3 INCHES...WITH
ISOLATED ADDITIONAL AMOUNTS OF 4 TO 7 INCHES POSSIBLE WHERE
TRAINING OF STORMS OCCURS. FLASH FLOODING WILL BE POSSIBLE IN
AREAS WHERE THE HEAVIEST RAIN OCCURS. THE GREATEST THREAT OF
FLOODING WILL BE TO THE NORTH OF A LINE FROM COLUMBUS TO CONROE
TO LIVINGSTON WHERE THE HEAVIEST RAIN HAS FALLEN SO FAR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLOOD WATCH MEANS THERE IS A POTENTIAL FOR FLOODING BASED ON
CURRENT FORECASTS.

YOU SHOULD MONITOR LATER FORECASTS AND BE ALERT FOR POSSIBLE
FLOOD WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE
PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP.

[jasons2k]

Jeff Lindner 7:38 AM

Threat for excessive to heavy rainfall remains.

Large complex of thunderstorms once again approaching from the west and starting to develop across the region. Rainfall rates of 2-4 inches per an hour are common with this complex.

Numerous thunderstorms will develop and track across SE TX nearly all day as strong 250mb flow remains divergent and surface boundary currently lifting northward across the area adds a surface focus.

Flash Flood Watch remains in effect until 900pm this evening

Additional rainfall amounts of 1-3 inches widespread with isolated 4-7 inches will be possible and a few locations as noted yesterday could get a rapid 10 inches. Given wet grounds flooding and flash flooding will be possible

[srainhoutx]

So much for my squall line idea. MCS developing rapidly near Central TX. Rough day ahead and thankfully there will not be 10,000+ bike riders on the road today for the MS-150.

[vbhoutex]

So much for my squall line idea. MCS developing rapidly near Central TX. Rough day ahead and thankfully there will not be 10,000+ bike riders on the road today for the MS-150.

So much for the idea that the atmosphere was too worked over yesterday too!! My eyes popped out of my head just now when I opened up radars!!! This is a hugely unstable air mass to be able to develop another huge MCS after yesterday's event! It gives me pause to think what could be in store for some today. Those poor people in our Western(SE TX) counties are going to be fighting some massive flooding I fear.
Unfortunately the call to cancel the first leg of the MS 150 was a good call and I won't be surprised if they cancel it altogether or reschedule it. It is a huge fundraiser for MS so I hope they can reschedule it.

[srainhoutx]

Lastest Update from SPC...

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0743 AM CDT SAT APR 18 2009

VALID 181300Z - 191200Z

...THERE IS A SLGT RISK OF SVR TSTMS TODAY THROUGH EARLY TONIGHT
FROM SE TX/SRN LA NNWWD INTO OK/KS...

...SYNOPSIS...
THE CLOSED MID LEVEL LOW CENTERED OVER NE NM AS OF 12Z WILL MOVE EWD
OVER KS/OK/TX...AND BEGIN TO EVOLVE INTO AN OPEN WAVE OVERNIGHT IN
RESPONSE TO UPSTREAM HEIGHT FALLS WITH A SHORTWAVE TROUGH CRESTING
THE NRN ROCKIES RIDGE. SEVERAL CLUSTERS OF THUNDERSTORMS ARE
EXPECTED TODAY IN ADVANCE OF THIS SYSTEM...WITH THE PRIMARY THREAT
AREAS FROM SE TX INTO LA...AND NEAR THE COLD CORE MID LEVEL LOW
ACROSS OK/KS.
...S CENTRAL TX EWD INTO LA TODAY THROUGH TONIGHT...
A CLUSTER OF THUNDERSTORMS THAT DEVELOPED EARLIER THIS MORNING OVER
S CENTRAL TX WILL LIKELY PERSIST WHILE GRADUALLY EXPANDING EWD/NEWD
ACROSS E/SE TX INTO LA LATER TODAY AND CONTINUING INTO TONIGHT. AN
INFLUX OF 68-72 F BOUNDARY LAYER DEWPOINTS AND LOW-LEVEL WAA...IN
THE WAKE OF CONVECTION THAT WEAKENED EARLY LAST NIGHT OVER SRN LA
AND THE ADJACENT NW GULF OF MEXICO...WILL HELP MAINTAIN MODERATE
INSTABILITY AND A FAVORABLE ENVIRONMENT FOR CONTINUED THUNDERSTORM
DEVELOPMENT IN ADVANCE OF THE ONGOING CONVECTION. MODEST LOW-LEVEL
AND DEEP LAYER SHEAR...IN COMBINATION WITH MLCAPE OF 1500-2000 J/KG
ON THE SRN FRINGE OF THE CONVECTIVE CLUSTER...WILL SUPPORT A FEW
EMBEDDED SUPERCELL/BOW STRUCTURES WITH AN ACCOMPANYING THREAT FOR
LARGE HAIL/DAMAGING WINDS...AND PERHAPS A BRIEF TORNADO.

...OK/KS AREA LATER THIS AFTERNOON/EVENING...
RESIDUAL BOUNDARY LAYER DEWPOINTS IN THE MID 50S AND SOME CLOUD
BREAKS WITHIN THE MID LEVEL DRY SLOT WILL ALLOW SUFFICIENT SURFACE
HEATING FOR MLCAPE VALUES TO APPROACH 1000 J/KG BY MID-LATE
AFTERNOON FROM SRN KS INTO NRN/CENTRAL OK. THUNDERSTORM DEVELOPMENT
IS EXPECTED BY EARLY-MID AFTERNOON NEAR THE WRN OK/TX BORDER INTO SW
KS ALONG THE SURFACE FRONT...AND STORMS WILL THEN SPREAD EWD TO THE
I-35 CORRIDOR DURING THE EVENING. COOL MID LEVEL TEMPERATURES /-20
C AT 500 MB/ WITH THE MID LEVEL TROUGH...AND EFFECTIVE BULK SHEAR
OF 35-45 KT ON THE CYCLONIC SIDE OF THE MID LEVEL JET CORE...WILL
SUPPORT A THREAT FOR LARGE HAIL WITH BOTH LEFT AND RIGHT MOVING
SUPERCELLS.

...CENTRAL/N TX THROUGH EARLY TONIGHT...
THE PROSPECTS FOR STRONG/SEVERE STORM DEVELOPMENT THIS
AFTERNOON/EVENING ALONG THE SURFACE FRONT WILL BE STRONGLY MODULATED
BY THE RESIDUAL EFFECTS OF THE ONGOING CONVECTION FROM S CENTRAL
INTO E TX. CLOUDS AND MAINTENANCE OF THE A RAIN-COOLED BOUNDARY
LAYER WILL TEND TO LIMIT INSTABILITY COMPARED TO AREAS FARTHER S IN
THE WARM SECTOR NEAR THE COAST...AND FARTHER N NEAR THE MID LEVEL
COLD CORE OVER OK/KS. THE SEVERE THREAT MAY EVOLVE IN A BIMODAL
SENSE WITH A RELATIVE MINIMUM IN THE THREAT SOMEWHERE ACROSS
CENTRAL/N TX AS A RESULT OF THE AFOREMENTIONED FACTORS.
HOWEVER...IT IS DIFFICULT TO CLEARLY DELINEATE THE LESSER THREAT
AREA GIVEN THE PROSPECTS FOR HAIL WITH ELEVATED STORMS TODAY...SO A
SLIGHT RISK WILL BE MAINTAINED IN THIS UPDATE.

..THOMPSON/GRAMS.. 04/18/2009

[JenBayles]

My eyes are popping too! I was shocked and amazed to see the little storms develop over us last night, but THIS is nuts!

Looks like more areas south of I-10 will get in on today's action. I'm headed out to blow a couple inches of water out of the pool. It's getting really dark, streetlights coming on, and a few brown outs to the electricity for the past 30 minutes.

[JenBayles]

lol - same here. I just got out of the shower to the sound of hard rain. A little red cell just went over my area. I thought it was done for the night, but there's quite a few storms developing out there. You were right, Jen.

Aaahhhh! Music to my ears. If only my husband would listen!

[jasons2k]

We are getting gusts here near 30 mph. And this isn't even with a storm - just strong winds under the LLJ.

[HURAKAN]

[srainhoutx]

Same areas getting it hit today...

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
839 AM CDT SAT APR 18 2009

TXC123-149-177-255-285-287-493-181645-
/O.CON.KEWX.FF.W.0003.000000T0000Z-090418T1645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LEE TX-FAYETTE TX-GONZALES TX-LAVACA TX-WILSON TX-DEWITT TX-KARNES TX-
839 AM CDT SAT APR 18 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 AM CDT FOR
KARNES...DEWITT...SOUTHEASTERN WILSON...LAVACA...SOUTHERN GONZALES...
FAYETTE AND SOUTHEASTERN LEE COUNTIES...

AT 837 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
DETECT THUNDERSTORMS PRODUCING FLASH FLOODING OVER THE WARNED AREA.
MODERATE TO HEAVY RAINS WERE NOTED ACROSS MUCH OF THE AREA. THE
HEAVIEST RAINS WERE FROM YORKTOWN TO HALLETTSVILLE. RAINFALL RATES
OF 2 TO 3 INCHES PER HOUR WERE ESTIMATED.

LOCATIONS IN THE WARNING AREA INCLUDE HALLETTSVILLE...SUBLIME...
SCHULENBURG...ROUND TOP...MOULTON...LA GRANGE...FLATONIA AND
FAYETTEVILLE.

[srainhoutx]

Another Update from Jeff Lindner...

Another rough day in store for much of SE TX and SC TX. Flooding already ongoing this morning in areas hit very hard yesterday with 10-11 inches of rainfall. Next MCS approaching from the west this morning...however cells have been weakening with time except along the southern flank where severe HP supercell is tracking. Coastal outflow boundary from yesterday is rapidly lifting northward across the region with isolated thunderstorms developing out ahead of the main line. These cells will have a tornado threat this morning as low level shear is maximized across SE TX. Large slow moving MCS will spread across the region with excessive rainfall and hail/wind damage threat today. Biggest threat will be continued very heavy hourly rainfall totals. Flash Flood guidance has taken a serious hit in the last 24 hours with widespread 4-5 inches of rain across much of our western and central counties. Even in areas with exceptional drought, nearly all the rainfall deficits were erased yesterday...very impressive and now flood waves are being generated on area watersheds. Parameters remain in place for excessive rainfall given surging PWS up to 1.8 inches, strong 250mb divergence, good low level jet convergence, and repeat cell training which resulted in the issues yesterday. Hourly rainfall rates of 1-3 inches per hour will be possible. Additional rainfall totals of 2-3" widespread with 4-6 inches isolated will be possible. On top of the rains yesterday this may push 2-day totals of 10-15 inches across portions of Colorado, Austin, Fayette, and Washington counties. Flash Flood Watch in effect until 900pm tonight Severe Thunderstorms Watch in effect until 1100am for areas mainly west of I-45 Flood Warning for the Colorado River near Columbus: river is currently near crest around action stage...however additional rainfall may result in a secondary river. River at Wharton is forecast to rise above action stage San Bernard River at East Bernard: River is forecast to rise near action stage and crest near flood stage...forecast may be slightly higher with additional rainfall. Additional excessive rainfall today will result in additional rises and slower recessions.

[HouTXmetro]

Well the good news is that this should almost bust the Central TX drought.

[jasons2k]

MESOSCALE DISCUSSION 0511
NWS STORM PREDICTION CENTER NORMAN OK
0947 AM CDT SAT APR 18 2009

AREAS AFFECTED...PORTIONS E-CENTRAL/SE TX.

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON

VALID 181447Z - 181515Z

TORNADO WW WILL BE ISSUED WITHIN MOMENTS FOR EMBEDDED/SMALL
SUPERCELLS DEVELOPING AND TIGHTENING CIRCULATIONS RAPIDLY WITHIN
BROAD AREA OF RAIN AND TSTMS OVER DISCUSSION AREA. WW WILL PARTLY
OVERLAP/REPLACE ERN PORTIONS WW 164.