MESO: Mesoscale Discussion 2184

ACUS11 KWNS 171939
SWOMCD
SPC MCD 171938
TXZ000-OKZ000-172115-

MESOSCALE DISCUSSION 2184
NWS STORM PREDICTION CENTER NORMAN OK
0238 PM CDT SAT SEP 17 2011

AREAS AFFECTED...PORTIONS OF WRN/SWRN OK...ERN TX
PANHANDLE...NWRN/WRN TX

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 171938Z - 172115Z

SCATTERED THUNDERSTORMS ARE FORECAST TO DEVELOP ACROSS PORTIONS OF
WRN/SWRN OK...THE ERN TX PANHANDLE AND NWRN/WRN TX DURING MID TO
LATE AFTERNOON. THESE STORMS WILL LIKELY POSE A THREAT FOR LARGE
HAIL AND DAMAGING WINDS. A SVR THUNDERSTORM WATCH WILL PROBABLY BE
NEEDED.

LATEST SURFACE OBSERVATIONS AND VIS SATELLITE IMAGERY SHOW A WARM
FRONT LIFTING TOWARD NRN OK...WITH RICH BOUNDARY LAYER MOISTURE
/DEWPOINTS IN THE MID TO UPR 60S/ ADVECTING NWD ACROSS N-CNTRL TX
INTO CNTRL OK. SURFACE CONFLUENCE ZONE EXTENDS SWD FROM THE WARM
FRONT...LOCATED NEAR THE OK/TX PANHANDLE BORDER INTO NWRN/WRN
TX...AND IS AIDING IN SHARPENING A DRYLINE. IN ADDITION...SURFACE
TEMPERATURES ARE WARMING THROUGH THE 80S TO AROUND 90 ALONG AND W OF
THE DRYLINE...WHICH IS RESULTING IN STRONG BOUNDARY LAYER
DESTABILIZATION AND TOWERING CUMULUS GROWTH ALONG THE DRYLINE.
THOUGH LARGE-SCALE FORCING FOR ASCENT WILL BE RATHER WEAK THROUGH
THE AFTERNOON...CONVERGENCE AND CONTINUED DESTABILIZATION ALONG THE
DRYLINE SHOULD BE SUFFICIENT FOR SCATTERED THUNDERSTORM DEVELOPMENT
BY 22Z. COMBINATION OF STEEP MIDLEVEL LAPSE RATES /AROUND 7 C PER
KM/ AND MOIST BOUNDARY LAYER AIRMASS WILL LIKELY YIELD MLCAPE VALUES
NEAR 3000 J/KG BY PEAK HEATING. THE STRONG INSTABILITY COMBINED WITH
MODERATE MIDLEVEL SWLYS /NEAR 30 KT/ OVERSPREADING 20 KT LOW-LEVEL
SLYS WILL RESULT IN FAVORABLE VERTICAL WIND PROFILES FOR A FEW
SUPERCELLS. PRIMARY SVR WEATHER THREATS WITH THESE STORMS WILL BE
LARGE HAIL AND DAMAGING WINDS.

..GARNER.. 09/17/2011

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

ATTN...WFO...FWD...OUN...SJT...LUB...AMA...MAF...

LAT...LON 35489815 34539766 33399820 32319963 32030105 32830193
35749983 35489815

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