Severe Weather - March 25-28 - Mid/Deep South/OH Riv Valley

[Bunkertor]

WRF now plotting 3500 J/kg for nern TX at 0z

3700 now. Theta e´s forecast at ~300. So strong capping might be the main problem at that time of the day.

[KWT]

Nice little squall line seems to have set-up overnight. In the end looks like we did get some decent activity then.

[KWT]

000
WUUS54 KBMX 261144
SVRBMX
ALC027-037-123-261230-
/O.NEW.KBMX.SV.W.0066.090326T1144Z-090326T1230Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BIRMINGHAM AL
644 AM CDT THU MAR 26 2009

THE NATIONAL WEATHER SERVICE IN BIRMINGHAM HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHEASTERN CLAY COUNTY IN EAST CENTRAL ALABAMA...
NORTHEASTERN COOSA COUNTY IN EAST CENTRAL ALABAMA...
THIS INCLUDES THE CITIES OF...KELLYTON...GOODWATER...
NORTHERN TALLAPOOSA COUNTY IN EAST CENTRAL ALABAMA...
THIS INCLUDES THE CITY OF ALEXANDER CITY...

* UNTIL 730 AM CDT

* AT 643 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
OF 60 MPH. THIS STORM WAS LOCATED NEAR KELLYTON...AND MOVING
NORTHEAST AT 45 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
GOLDVILLE AND 6 MILES NORTHWEST OF NEW SITE BY 700 AM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT UNTIL 900 AM CDT THURSDAY MORNING
FOR SOUTHEASTERN ALABAMA.

&&

LAT...LON 3283 8607 3308 8608 3337 8564 3312 8565
3311 8559 3296 8559
TIME...MOT...LOC 1144Z 236DEG 40KT 3301 8600

$$

[Bunkertor]

KWT: Can you - or others - interpret this sounding for Waco ?

[CrazyC83]

Waco sounding: plenty of juice, but CINH of 54 may hold things off.

[RL3AO]

And the LCL is pretty high. Not too supportive of tornadoes.

Also, the lapse rate and freezing level will support some medium to large hail.

[Bunkertor]

But LFC<LCL means enviroment is supportive for buoyancy. Or am i wrong ?

[RL3AO]

LFC (level of free convection) is at 748mb which is around 2450m above the ground.

LCL (lifting condensation level) which is where the clouds begin to form. In this case its at 793mb or around 1950m.

From my understanding, tornadoes are more favorable if the LCL is under 1500m.

I'm guessing thats why Waco is only under a 2% tornado risk.

[Bunkertor]

Ah, Sorry, mate. I messed it up by mixing the mbars.

[RL3AO]

Heres a sounding from Tyler, TX.



Looking at the SPC outlook, if something can get going, there could be some supercells in Texas. Its just the upper air support isn't great and theres not many boundaries for storms to fire along.

[srainhoutx]

12z RUC has it very unstable(CAPE >3000) over Central / Eastern TX with 25-40Kt LLJ(higher north) to play with and 50-60 500 MB flow. Also convection is starting W of San Antonio already. Looks like a more linear event in TX today, but would not rule out some rotating Meso's.

[Ed Mahmoud]

Cloud cover is pretty persistent here around HOU.


I remember a year ago, right about this time, a significant severe weather event was expected, TWC even sent someone to CLL, but the low clouds never much broke, and it was mostly garden variety storms with just a couple becoming marginally severe.


I'd expect the same if the clouds don't burn off, but, solar time, it is only a bit after 8 am. However, the near shore Gulf waters are cooler than the deeper Gulf waters, and on calm days form fog, breezy days a slow to burn off stratus or strato-cu deck.


That dark blue blob offshore SE Texas tempers many a SE Texas severe weather outbreak.

[srainhoutx]

MESOSCALE DISCUSSION 0272
NWS STORM PREDICTION CENTER NORMAN OK
0914 AM CDT THU MAR 26 2009

AREAS AFFECTED...SOUTH CENTRAL TX

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

VALID 261414Z - 261445Z

MOISTURE IS RECOVERING NICELY ACROSS THE RIO GRANDE VALLEY INTO
SCNTRL TX THIS MORNING AHEAD OF SHEARING UPPER VORT LOCATED NEAR
DRT. THIS UPPER FEATURE WILL EJECT EWD TOWARD THE UPPER TX COAST
WHICH WILL FURTHER ENCOURAGE ASCENT AS LOW LEVEL WARM ADVECTION
INCREASES JUST NORTH OF RETREATING COASTAL BOUNDARY. CONVECTION HAS
STEADILY INCREASED OVER THE LAST HOUR FROM SRN VAL VERDE COUNTY INTO
UVALDE COUNTY ALONG NOSE OF HIGHEST INSTABILITY. GIVEN THESE TRENDS
IT APPEARS ELEVATED THUNDERSTORMS WILL EXPAND IN AREAL
COVERAGE/INTENSITY INTO THE EARLY AFTERNOON HOURS. LARGE HAIL IS
THE PRIMARY SEVERE THREAT UNTIL BOUNDARY LAYER COUPLES WITH UPDRAFTS
LATER THIS AFTERNOON.

..DARROW.. 03/26/2009


ATTN...WFO...CRP...EWX...

[Bunkertor]

There is a strong hailer in the region. One cell is dropping 2.75 "

[srainhoutx]

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 69
NWS STORM PREDICTION CENTER NORMAN OK
940 AM CDT THU MAR 26 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND SOUTH CENTRAL TEXAS

EFFECTIVE THIS THURSDAY MORNING AND AFTERNOON FROM 940 AM UNTIL
400 PM CDT.

HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60
STATUTE MILES EITHER SIDE OF A LINE FROM 15 MILES SOUTH OF DEL
RIO TEXAS TO 60 MILES SOUTHEAST OF AUSTIN TEXAS. FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU9).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 68...

DISCUSSION...ELEVATED STORMS HAVE DEVELOPED RAPIDLY OVER PARTS OF
SOUTH CENTRAL TEXAS WITH LEFT EXIT REGION OF STRONG SUBS TROPICAL
JET EXTENDING FROM NRN MEXICAN INTO THE NWRN GULF. AIR MASS IS VERY
UNSTABLE WITH MUCAPE TO 3000 J/KG...AND CLOUD LAYER SHEAR IS
SUFFICIENT TO SUPPORT SUPERCELL CHARACTERISTICS. VERY LARGE HAIL
WITH POSSIBLE WITH MOST INTENSE STORMS...AND DAMAGING WIND GUSTS
WILL ALSO BE POSSIBLE IF STORMS BECOME NEAR-SURFACE BASED DURING THE
AFTERNOON. ACTIVITY IS EXPECTED TO SPREAD ENEWD THROUGH THE EARLY
AFTERNOON HOURS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 25030.

[srainhoutx]

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1019 AM CDT THU MAR 26 2009

..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..

1015 AM HAIL YANCEY 29.15N 99.13W
03/26/2009 M1.00 INCH MEDINA TX LAW ENFORCEMENT

[KWT]

I don't think the tornado risk is too high today but I do suspect there will be a decent severe thunderstorm risk so does still require watching I suspect.

Still tomorrow looks like being the main event providing cloud cover doesn't get in the way.

[KWT]

000
WUUS54 KEWX 261525
SVREWX
TXC163-325-261630-
/O.NEW.KEWX.SV.W.0019.090326T1525Z-090326T1630Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1025 AM CDT THU MAR 26 2009

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTHEASTERN FRIO COUNTY...
SOUTHERN MEDINA COUNTY...

* UNTIL 1130 AM CDT.

* AT 1023 AM CDT...NWS METEOROLOGISTS HAVE DETECTED A SEVERE
THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL. THIS STORM
WAS LOCATED 6 MILES WEST OF YANCEY...OR 14 MILES SOUTH OF HONDO...
AND MOVING EAST AT 20 MPH.

* SOME LOCATIONS IN THE WARNING INCLUDE BIRY...MOORE...DUNLAY...
BADER...DEVINE...NOONAN...BIG FOOT...CASTROVILLE...PEARSON...
SCHATTEL AND NATALIA.

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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 PM CDT
THURSDAY AFTERNOON FOR SOUTH CENTRAL TEXAS.

&&

LAT...LON 2942 9882 2892 9883 2905 9931 2925 9932
TIME...MOT...LOC 1525Z 270DEG 17KT 2916 9921

$$

[KWT]

I don't know if this has been covered but I've heard a tornado has caused serious damage and injured 17, not sure exactly when this happened but its what I've heard.

[Texas Snowman]

KWT, where did you hear that info?