MESOSCALE DISCUSSION 0388
NWS STORM PREDICTION CENTER NORMAN OK
1221 PM CST SAT APR 05 2003
AREAS AFFECTED...WRN TX/EXTREME SWRN OK
CONCERNING...SEVERE THUNDERSTORM POTENTIAL
VALID 051821Z - 052115Z
VISIBLE SATELLITE IMAGERY AND HOURLY SURFACE OBSERVATIONS HAVE
SHOWN A RAPID NWWD INCREASE IN MOISTURE INTO PARTS OF WRN TX THIS
MORNING. CONTINUED NWD DESTABILIZATION TRENDS AND EARLY
DEVELOPMENT OF CONVECTION NEAR BGS SUGGEST THREAT OF SEVERE
THUNDERSTORMS WILL INCREASE THIS AFTERNOON. WW WILL LIKELY BE
ISSUED BEFORE 20Z.
GOES SOUNDER PRODUCTS SHOW RAPID RETURN OF MOISTURE AND
ASSOCIATED DESTABILIZATION INTO WEST CENTRAL TX AND WRN PARTS OF
NORTH CENTRAL TX. SURFACE DEW POINTS IN THE MID 50S ARE NOW AS
FAR NORTH AS ABI...AND THIS SHOULD SPREAD NWD TOWARD THE RED
RIVER DURING THE AFTERNOON. STRONG HEATING AND MODERATELY STEEP
MID LEVEL LAPSE RATES ASSOCIATED WITH 500 MB TEMPERATURES OF -14
TO -16C WILL CONTRIBUTE TO FURTHER DESTABILIZATION WITH MLCAPE
REACHING 1500-2000 J/KG BY MID AFTERNOON. JAYTON PROFILER SHOWS
WINDS GRADUALLY VEERING AND INCREASING WITH HEIGHT WITH
SUFFICIENT DEEP LAYER SHEAR TO SUPPORT SUPERCELL
DEVELOPMENT...AND EASTERLY COMPONENT TO LOW LEVEL WINDS NORTH OF
THIS AREA RESULTS IN GREATER LOW LEVEL SHEAR AND HELICITY. 12Z
MODELS INDICATE CONVECTION WILL DEVELOP NWD AND GRADUALLY
INCREASE BY MID/LATE LATE AFTERNOON ALONG AND EAST OF THE
DEVELOPING DRY LINE. THE FAVORABLE WIND SHEAR COUPLED WITH
INCREASING INSTABILITY INDICATES DISCRETE SEVERE STORMS WITH
THREAT FOR A FEW TORNADIC SUPERCELLS DEVELOPING BY MID/LATE
AFTERNOON. A TORNADO WATCH WILL LIKELY BE NEEDED BY 19-20Z.
..WEISS.. 04/05/2003
ATTN...WFO...OUN...SJT...LUB...MAF...
