MESO: Mesoscale Discussion 0349

ACUS11 KWNS 310614
SWOMCD
SPC MCD 310613
OKZ000-TXZ000-310715-

MESOSCALE DISCUSSION 0349
NWS STORM PREDICTION CENTER NORMAN OK
0113 AM CDT SUN MAR 31 2013

AREAS AFFECTED...PORTIONS EXTREME ERN TX PANHANDLE...WRN/SRN OK.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 69...

VALID 310613Z - 310715Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...ISOLATED TSTM STRENGTHENING OVER HEMPHILL COUNTY TX AS OF
06Z LIKELY IS FIRST MANIFESTATION OF CONVECTIVE EVENT THAT SHOULD
DEVELOP AND GROW UPSCALE ACROSS WRN OK THROUGH 10Z...AND MOVE ESEWD
ACROSS PORTIONS CENTRAL/SRN OK. MAIN THREAT IS LARGE HAIL. TSTMS
WITH ACCESS TO PREFRONTAL/WARM-SECTOR AIR NEAR SFC ALSO MAY PRODUCE
STG/ISOLATED DAMAGING GUSTS.

DISCUSSION...SFC MESOANALYSIS SHOWS FRONT FROM SRN PORTIONS TUL AREA
SWWD INVOF OUN THEN WWD PAST CSM TO NEAR AMA. BOUNDARY SHOULD
ACCELERATE SEWD AS STRENGTHENING COLD FRONT THROUGH REMAINDER
MORNING WITH WEAK FRONTAL-WAVE LOW POSSIBLE OVER NW TX.
STRENGTHENING FRONTOGENETIC FORCING IS FCST TO IMPINGE ON
PROGRESSIVELY GREATER WARM-SECTOR MOISTURE WITH SEWD EXTENT.
ALONG/AHEAD OF FRONT...SFC DEW POINTS MID-UPPER 50S F WILL
CONTRIBUTE TO 1000-1500 J/KG MLCAPE...REDUCED VERY SLOWLY AMIDST
PREFRONTAL WAA/MOIST ADVECTION. THESE FACTORS SHOULD OFFSET
DELETERIOUS EFFECTS OF SFC DIABATIC COOLING AND WEAK PREFRONTAL
WINDS ENOUGH TO CONTRIBUTE TO ADDITIONAL DEVELOPMENT AND UPSCALE
GROWTH OF CONVECTION. ASSORTED STORM-MOTION ALGORITHMS APPLIED TO
FCST SOUNDINGS SUGGEST ACTIVITY FORMING ALONG FRONT MAY BE
UNDERCUT...BUT ONLY GRADUALLY...GIVEN ITS SEWD MOTION INFLUENCED BY
DEEP-LAYER WIND PROFILES ABOVE FRONTAL CURRENT.
ADDITIONALLY...STEEP LAPSE RATES AND MOISTURE ARE EXPECTED ABOVE
FRONTAL SFC AND WITHIN AT LEAST 75 NM BEHIND FRONT...WHERE ELEVATED
MUCAPE 500-1000 J/KG IS POSSIBLE AMIDST 35-45 KT EFFECTIVE SHEAR
MAGNITUDES.

..EDWARDS/KERR.. 03/31/2013

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

ATTN...WFO...TSA...FWD...OUN...LUB...AMA...

LAT...LON 35920024 35869908 35939777 35529651 35259642 34059640
33799728 34399951 34620008 35180036 35920024

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