MESO: Mesoscale Discussion 1628

ACUS11 KWNS 202042
SWOMCD
SPC MCD 202042
KSZ000-NEZ000-202245-

MESOSCALE DISCUSSION 1628
NWS STORM PREDICTION CENTER NORMAN OK
0342 PM CDT MON JUL 20 2009

AREAS AFFECTED...PORTIONS OF WRN AND CNTRL KS

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 202042Z - 202245Z

THE THREAT FOR SEVERE STORMS CAPABLE OF DAMAGING WINDS AND HAIL IS
EXPECTED TO INCREASE LATE THIS AFTERNOON INTO EVENING. A WW WILL
LIKELY BE REQUIRED PRIOR TO 22-23Z.

DEEPENING SURFACE LOW NEAR HLC WILL CONTINUE TO DO SO THIS AFTERNOON
BEFORE DEVELOPING SSEWD ALONG COLD FRONTAL SURGE PUSHING SWD THROUGH
WRN NEB. MEANWHILE TO THE E...DIFFERENTIAL HEATING HAS ENHANCED THE
BAROCLINITY OF A WARM FRONT WHICH EXTENDED FROM SURFACE LOW SEWD
THROUGH CNTRL KS INTO NERN OK. AIR MASS FROM VICINITY OF WARM FRONT
WWD TO PRE-FRONTAL TROUGH OVER WRN KS HAS WARMED THROUGH THE 80S.
WHEN COUPLED WITH DEWPOINTS IN THE 60S...BOUNDARY LAYER HAS BECOME
MODERATELY UNSTABLE WITH MLCAPE OF 1500-2500 J/KG AND A DECREASING
CAP.

CONTINUED BOUNDARY LAYER HEATING IN CONCERT WITH INCREASING
INFLUENCE OF SHORT WAVE TROUGH MOVING THROUGH THE CNTRL HIGH PLAINS
ARE EXPECTED TO EVENTUALLY FOSTER TSTM DEVELOPMENT OVER DISCUSSION
AREA LATER THIS AFTERNOON OR BY EARLY EVENING. REGIONAL
PROFILER/VWP AND LATEST SHORT TERM MODEL DATA INDICATE THAT MID AND
HIGH-LEVEL WIND FIELDS SHOULD GRADUALLY STRENGTHEN FROM THE NW IN
ASSOCIATION WITH SHORT WAVE TROUGH. THIS INCREASE IN VERTICAL SHEAR
IN CONJUNCTION WITH THE MODERATE INSTABILITY WILL SUPPORT THE
POTENTIAL FOR ORGANIZED STORMS INCLUDING SUPERCELLS WITH THE THREAT
FOR LARGE HAIL AND DAMAGING WINDS. WIND POTENTIAL MAY INCREASE
LATER TONIGHT AS CONVECTION GROWS UPSCALE INTO ONE OR MULTIPLE
MCS/S.

..MEAD.. 07/20/2009

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

ATTN...WFO...ICT...GID...DDC...GLD...

LAT...LON 38380115 39740057 40129986 39679872 38739781 37569753
37059826 37089930 37640040 38380115

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