SWOMCD
SPC MCD 120030
TXZ000-120230-
MESOSCALE DISCUSSION 2372
NWS STORM PREDICTION CENTER NORMAN OK
0630 PM CST TUE NOV 11 2008
AREAS AFFECTED...PORTIONS S TX.
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 120030Z - 120230Z
TSTMS MAY DEVELOP AND INCREASE IN COVERAGE OVER PORTIONS
MIDDLE-UPPER TX COASTAL PLAIN -- FROM ROUGHLY I-37 NEWD TOWARD
CORRIDOR BETWEEN HOU-SAT. STRONGER TSTMS MAY PRODUCE LARGE HAIL AND
ISOLATED DAMAGING GUSTS.
SFC MESOANALYSIS INDICATED VERY STG OUTFLOW BOUNDARY FROM EARLIER
MCS...EXTENDING FROM NEAR BPT WSWWD ACROSS SRN/WRN PORTIONS OF HOU
METRO AREA...THEN WNWWD INTO AUSTIN COUNTY...INTERSECTING ONGOING
NON-SVR CONVECTIVE BAND THERE. THIS BAND -- COLLOCATED WITH
PERSISTENT/QUASISTATIONARY LOW LEVEL CONVERGENCE ZONE -- BECAME MORE
BKN WITH SWWD EXTENT TO KARNES COUNTY. THERE...CONVERGENCE ZONE
INTERSECTED SEA BREEZE-REINFORCED CONFLUENCE LINE THAT EXTENDED SWD
THROUGH JIM WELLS COUNTY. LATTER BOUNDARY SHOULD DECELERATE/WEAKEN
AS DIURNAL/DIABATIC FORCING FOR SEA BREEZE SOLENOIDS
DIMINISHES...BUT CONFLUENT ZONE SHOULD REMAIN IN PLACE FOR A FEW
MORE HOURS. LATTER TWO BOUNDARIES ARE MOST LIKELY AREAS FOR
ADDITIONAL DEVELOPMENT...WHICH THEN WOULD MOVE INTO REGIME OF BACKED
SFC WINDS AND ENHANCED STORM-RELATIVE INFLOW CHARACTERISTIC OF
COASTAL AIR MASS E AND S OF THESE BOUNDARIES. ANOTHER BOUNDARY --
APPARENT FRONTAL/OUTFLOW COMBINATION -- IS MOVING SEWD ACROSS I-10
AREA ENE OF SAT AND WILL REINFORCE PRE-EXISTING ENE-WSW ALIGNED
CONVERGENCE BAND.
MARINE AIR MASS WILL BE CHARACTERIZED BY RELATIVELY MAXIMIZED
THETAE...WITH SFC DEW POINTS AROUND 70 F HELPING TO KEEP EFFECTIVE
LIFTED PARCELS ROOTED AT OR NEAR SFC FOR MUCH OF THIS EVENING.
WEAKNESSES IN LOW LEVEL WINDS JUST ABOVE SFC -- EVIDENT IN HOU/CRP
AREA VWP -- WILL LIMIT HODOGRAPH SIZE...ALTHOUGH 40-50 KT OF
DEEP-LAYER/EFFECTIVE SHEAR INDICATES SUPERCELL POTENTIAL. LARGE
SCALE ASCENT/DESTABILIZATION ALOFT IS EXPECTED TO INCREASE BY ABOUT
06Z AS SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY
OVER FAR W TX AND ADJACENT PORTIONS NM/CHIHUAHUA -- PIVOTS EWD
TOWARD REGION. MODIFIED 00Z CRP RAOB AND RUC SOUNDINGS INDICATE
MLCAPES 1000-2000 J/KG SHOULD BE MAINTAINED IN MARINE AIR
MASS...CINH INCREASING AND INITIATION PROBABILITY DECREASING WITH
SWD EXTENT FROM MIDDLE-LOWER TX COASTAL PLAIN. DEEP/STABLE BOUNDARY
LAYER AND WEAK ELEVATED CAPE NE OF HOU/BPT AREA OUTFLOW BOUNDARY
INDICATES MRGL HAIL THREAT AT BEST WITH ANY CONVECTION MOVING NEWD
ATOP COLD POOL.
..EDWARDS.. 11/12/2008
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...HGX...CRP...EWX...
LAT...LON 28039831 29299792 29929713 30279628 30139550 29539541
28669654 27619725 28039831
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