MESO: Mesoscale Discussion 1698

ACUS11 KWNS 121558
SWOMCD
SPC MCD 121557
ILZ000-MOZ000-ARZ000-121730-

MESOSCALE DISCUSSION 1698
NWS STORM PREDICTION CENTER NORMAN OK
1057 AM CDT MON AUG 12 2013

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

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 121557Z - 121730Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...AN ISOLATED SEVERE THREAT MAY PERSIST ACROSS SRN MO LATE
THIS MORNING AND COULD EXPAND IN COVERAGE EARLY THIS AFTERNOON.
STRONG GUSTY WINDS AND HAIL WILL LIKELY BE THE PRIMARY THREATS. DUE
TO THE MARGINAL NATURE OF THE THREAT...WW ISSUANCE APPEARS UNLIKELY.

DISCUSSION...A CLUSTER OF STRONG THUNDERSTORMS IN SW AND CNTRL MO IS
LOCATED JUST AHEAD OF A PRONOUNCED VORTICITY MAXIMA EVIDENT ON WATER
VAPOR IMAGERY IN THE KANSAS CITY AREA. LARGE-SCALE ASCENT ASSOCIATED
WITH THE VORT MAX SHOULD RESULT IN AN GRADUAL EXPANSION OF STORM
COVERAGE OVER THE NEXT FEW HOURS. AHEAD OF THE
CONVECTION...MESOANALYSIS SHOWS MODERATE INSTABILITY IN PLACE WITH
MLCAPE ESTIMATED IN THE 1500 TO 2500 J/KG RANGE. THIS COMBINED WITH
ABOUT 40 KT OF 0-6 KM SHEAR ON THE ST LOUIS AND SPRINGFIELD MO
WSR-88 VWPS SHOULD BE ENOUGH TO CONTINUE A MARGINAL SEVERE THREAT.
VISIBLE SATELLITE IMAGERY CURRENTLY SHOWS CLEARING ACROSS MUCH OF
SRN MO AND NRN AR SUGGESTING LOW-LEVEL LAPSE RATES WILL STEEPEN
THROUGH EARLY THIS AFTERNOON. IN ADDITION...A VERY MOIST AIRMASS IS
IN PLACE WITH SFC DEWPOINTS IN THE LOWER TO MID 70SF. THIS MAY
ENABLE THE STRONGER CELLS TO PRODUCE MARGINALLY SEVERE WIND GUSTS.
HAIL COULD ALSO OCCUR ESPECIALLY AS INSTABILITY INCREASES INTO EARLY
AFTERNOON.

..BROYLES/KERR.. 08/12/2013

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

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

LAT...LON 38408987 38699111 38729239 38539361 37959414 37399410
36469368 36139285 35609172 35779062 36098981 37438928
38408987

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