Wednesday, April 3, 2013

MESO: Mesoscale Discussion 0380

ACUS11 KWNS 030637
SWOMCD
SPC MCD 030636
TXZ000-030830-

MESOSCALE DISCUSSION 0380
NWS STORM PREDICTION CENTER NORMAN OK
0136 AM CDT WED APR 03 2013

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

CONCERNING...SEVERE THUNDERSTORM WATCH 81...

VALID 030636Z - 030830Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 81
CONTINUES.

SUMMARY...ISOLATED DAMAGING-WIND THREAT MAY EXIST FROM
ELEVATED/BOWING PART OF COMPLEX AS IT MOVES EWD ALONG AND S OF I-10
TOWARD HOU AREA. THREAT APPEARS TOO MRGL/CONDITIONAL ATTM FOR
ADDITIONAL WW. MEANWHILE..THOUGH TRAILING PART OF COMPLEX HAS
WEAKENED...ISOLATED SVR WIND/HAIL THREAT PERSISTS OVER CORRIDOR FROM
MCMULLEN COUNTY EWD TO COASTLINE BETWEEN LAVACA-NUECES COUNTIES.

DISCUSSION...SFC MESOANALYSIS SHOWED OUTFLOW BOUNDARY -- FROM
COMPLEX DISCUSSED IN SPC MESOSCALE DISCUSSION 379 -- EXTENDING FROM
JUST OFFSHORE GLS WSWWD OVER SHELF WATERS TO NEAR RKP...MOVING
SLOWLY SWWD. PRIMARY PORTION OF MCS IS NE OF WW...N OF THAT
BOUNDARY...AND MOVING EWD 40-45 KT ACROSS AREA FROM VCT TO I-10
CORRIDOR. SFC AIR MASS S OF OUTFLOW BOUNDARY WILL REMAIN
SUBSTANTIALLY MORE UNSTABLE THAN THAT TO ITS N. ACCORDINGLY
MODIFIED FCST SOUNDINGS SUGGEST DEEP LAYER OF NEARLY SATURATED
THERMODYNAMIC PROFILE WITH MUCAPE RANGING FROM AROUND 500 J/KG ALONG
I-10 TO 1500 J/KG NEAR BOUNDARY. DEPTH OF NLYS IN HGX VWP INDICATE
ROUGHLY 1 KM DEEP STABLE LAYER...WHICH SHOULD BECOME MORE SHALLOW
WITH SWWD EXTENT. WLY EFFECTIVE-SHEAR VECTORS WITH 45-50 KT
MAGNITUDE ARE EVIDENT IN AVAILABLE VWP AND FCST SOUNDINGS. GIVEN
THESE FACTORS...OCNL STG-DAMAGING GUSTS...BUT LARGELY BELOW 50-KT
SVR CRITERIA...MAY PENETRATE STABLE OUTFLOW LAYER TO SFC.

FARTHER SW...ANY CONVECTION THAT CAN ACCESS BOUNDARY-LAYER AIR MASS
FROM WW EWD TO COAST WILL ENCOUNTER MLCAPE 1000-1500 J/KG....AMIDST
50-60 KT EFFECTIVE SHEAR MAGNITUDE. WHILE THESE FACTORS ARE
FAVORABLE...TSTM COVERAGE IS IN DOUBT. STRONGER EML-RELATED MLCINH
IS APPARENT WITH SWWD EXTENT...WHICH APPEARS TO BE SUPPRESSING
ADDITIONAL DEVELOPMENT ALONG TRAILING COLD-POOL EDGE. THAT OUTFLOW
SHOULD BECOME MORE SHALLOW WITH TIME...LIMITING LIFT.

..EDWARDS.. 04/03/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LCH...HGX...CRP...EWX...

LAT...LON 28199876 28529778 29199693 29909684 30079410 29869398
29679405 29419465 29309475 28849537 28459621 28309643
27939697 27809710 27769843 28199876

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