MESO: Mesoscale Discussion 0389

ACUS11 KWNS 132051
SWOMCD
SPC MCD 132051
ARZ000-LAZ000-TXZ000-OKZ000-132215-

MESOSCALE DISCUSSION 0389
NWS STORM PREDICTION CENTER NORMAN OK
0351 PM CDT THU MAR 13 2008

AREAS AFFECTED...EASTERN OK/NORTHEAST TX INTO WESTERN AR/NORTHWEST
LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 132051Z - 132215Z

MONITORING FOR INCIPIENT THUNDERSTORM DEVELOPMENT AND AN INCREASING
SEVERE RISK LATE THIS AFTERNOON ACROSS EASTERN OK/NORTHEAST
TX...INTO WESTERN AR/NORTHWEST LA. IT APPEARS LARGE HAIL WILL BE THE
PRIMARY HAZARD...ALTHOUGH STRONG WIND GUSTS AND PERHAPS A TORNADO
WILL BE POSSIBLE AS WELL. CURRENT THINKING IS THAT A WATCH MAY BE
NEEDED AS EARLY AS 22Z.

WATER VAPOR IMAGERY FEATURES A PROGRESSIVE/RELATIVELY LOW AMPLITUDE
SHORTWAVE TROUGH TRANSITIONING EASTWARD ACROSS WESTERN OK/WEST
CENTRAL TX AT MID AFTERNOON. AT THE SURFACE...A 1000 MB SURFACE LOW
IS ANALYZED ACROSS SOUTH CENTRAL OK...WITH AN ATTENDANT
DRYLINE/TRAILING PACIFIC FRONT EXTENDING INTO NORTH CENTRAL TX JUST
WEST OF DALLAS-FORT WORTH. AHEAD OF THESE FEATURES...LOW LEVEL
SOUTHERLY MOIST TRAJECTORIES HAVE LEAD TO A STEADY NORTHWARD
PROGRESSION OF A MODIFIED GULF AIRMASS ACROSS EASTERN TX/SOUTHEAST
OK THROUGH EARLY AFTERNOON...WITH MODEST MOISTURE AS CHARACTERIZED
BY 50S TO LOWER 60S F SURFACE DEWPOINTS AS OF 20Z. BENEATH A
PRONOUNCED ELEVATED MIXED LAYER PER 12Z RAOBS/RUC
SOUNDINGS...EXTENSIVE STRATUS HAS RETARDED HEATING THUS FAR
COINCIDENT WITH THE LOW LEVEL MOIST AXIS...AND THIS CLOUD
COVER/INHIBITION COMPLICATES THE CONFIDENCE IN TRUE SURFACE BASED
DEVELOPMENT LATER THIS AFTERNOON/EARLY EVENING. REGARDLESS...IT
APPEARS LIKELY THAT THUNDERSTORMS WILL INCREASE ACROSS EASTERN
OK/NORTHEAST TX BETWEEN 22Z-01Z GIVEN INCREASING LARGE SCALE
ASCENT/DESTABILIZATION...WITH A RISK OF AT LEAST LARGE HAIL GIVEN
THE VERY STEEP MID LEVEL LAPSE RATES.

.GUYER.. 03/13/2008

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

ATTN...WFO...LZK...SHV...TSA...FWD...OUN...

35869604 35859450 34879340 32279376 31859624 32509719
33889679

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