MESO: Mesoscale Discussion 0668

ACUS11 KWNS 171929
SWOMCD
SPC MCD 171929
TXZ000-172030-

MESOSCALE DISCUSSION 0668
NWS STORM PREDICTION CENTER NORMAN OK
0229 PM CDT FRI MAY 17 2013

AREAS AFFECTED...TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 171929Z - 172030Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...AT LEAST ISOLATED STORM DEVELOPMENT EXPECTED ALONG THE
DRYLINE ACROSS CNTRL AND NW TX IN THE NEXT 1-2 HOURS. IF CONVECTION
CAN INITIATE BY OVERCOMING STRONG INHIBITION...IT MAY BE FUELED BY
POCKETS OF EXTREME INSTABILITY TO RESULT IN VERY LARGE HAIL AND
DAMAGING DOWNBURST WINDS.

DISCUSSION...DESPITE GENERALLY WEAK LARGE SCALE FORCING FOR ASCENT
WITH BROAD RIDGING DEVELOPING ACROSS WEST TEXAS THIS
AFTERNOON...LOCALIZED MIXING ALONG A SHARP DRYLINE MAY BE SUFFICIENT
FOR ISOLATED TSTM INITIATION IN THE NEXT FEW HOURS AS SFC TEMPS WARM
INTO THE UPPER 90S AND LOWER 100S F. VSBL IMAGERY ALREADY DEPICTS
GROWING CU/TCU FIELD ACROSS MCCULLOCH COUNTY WITH FEW CU ALSO
DEVELOPING FARTHER NORTH AHEAD OF DRYLINE BULGE IN THE
SHACKELFORD/STEPHENS COUNTY LINE. LATEST HRRR INDICATES POTENTIAL
EXPLOSIVE BUT VERY LOCAL STORM DEVELOPMENT AMIDST HIGH MLCAPE AROUND
3000 J/KG. LACK OF STRONGER FLOW/SHEAR DOES INTRODUCE UNCERTAINTY
REGARDING STORM PERSISTENCE/LONGEVITY. HOWEVER...DEGREE OF
INSTABILITY AND SFC T/TD SPREADS OVER 30F WOULD SUPPORT BOTH LARGE
HAIL AND DOWNBURST WIND HAZARDS NOT LONG AFTER STORM INITIATION. IF
TCU/STORM DEVELOPMENT TRENDS INCREASE IN THE NEXT HOUR OR SO...A
WATCH IS POSSIBLE.

..CARBIN/WEISS.. 05/17/2013

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

ATTN...WFO...FWD...OUN...SJT...

LAT...LON 33599787 33059764 32469778 32289782 31879811 31609835
31339875 31179899 30999945 30939995 31529963 31839951
32149935 32459931 32889924 33299931 33689966 33859977
34019971 34129954 34149918 34049881 33909835 33829816
33599787

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