SPC MD 2064

MD 2064 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR NRN AR…SRN/CNTRL MO


MESOSCALE DISCUSSION 2064
NWS STORM PREDICTION CENTER NORMAN OK
1255 PM CDT WED OCT 17 2012

AREAS AFFECTED...NRN AR...SRN/CNTRL MO

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 171755Z - 171930Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A LINE OF THUNDERSTORMS IS FORECAST TO DEVELOP FROM CNTRL
MO SWWD INTO NRN AR THIS AFTERNOON. AREA IS BEING MONITORED FOR
INCREASING THREAT OF DAMAGING WINDS/MARGINALLY SVR HAIL AND AN
ISOLATED TORNADO. WW IS POSSIBLE.

DISCUSSION...MESOANALYSIS AT 17Z SHOWS AN AREA OF SURFACE LOW
PRESSURE OVER ERN OK...WITH A COLD FRONT EXTENDING NEWD INTO NRN MO.
VISIBLE SATELLITE IMAGERY SHOWS THAT SOME CLEARING OF LOW-LEVEL
STRATUS IS OCCURRING AHEAD OF THE FRONT FROM NWRN AR INTO S-CNTRL
MO...WHICH IS AIDING IN TEMPERATURES WARMING INTO THE MID 60S. IN
ADDITION...SURFACE DEWPOINTS ARE SLOWLY RISING INTO THE UPPER 50S TO
LOW 60S. THIS SURFACE AIRMASS COMBINED WITH STEEP MIDLEVEL LAPSE
RATES WILL YIELD AFTERNOON MLCAPE VALUES FROM 1000 J/KG OVER NRN AR
TO AROUND 500 J/KG IN CNTRL MO. SATELLITE IMAGERY INDICATES A BAND
OF FORCED ASCENT IS SPREADING EWD ACROSS ERN KS...AND IS LIKELY
SUPPORTING THE RECENT INITIATION OF THUNDERSTORMS ALONG THE COLD
FRONT. THESE STORMS ARE FORECAST TO ACCELERATE EWD ACROSS NRN AR AND
SRN/CNTRL MO DURING THE AFTERNOON. GIVEN THE MARGINAL BUOYANCY...IT
IS UNCERTAIN WHETHER STORMS WILL INTENSIFY TO SVR LEVELS.
HOWEVER...STRONG FORCING FOR ASCENT AND VERTICAL WIND SHEAR PROFILES
MAY COMPENSATE...AND SUPPORT A THREAT FOR DAMAGING WIND
GUSTS...MARGINALLY SVR HAIL...AND PERHAPS AN ISOLATED TORNADO.

..GARNER/THOMPSON.. 10/17/2012

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

ATTN...WFO...PAH...LSX...LZK...SGF...TSA...

LAT...LON   38269059 37319059 36089253 36039427 37169461 37959399
            38719211 38269059

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md2064.html