MESO: Mesoscale Discussion 1224

ACUS11 KWNS 071955
SWOMCD
SPC MCD 071954
MNZ000-IAZ000-NEZ000-072130-

MESOSCALE DISCUSSION 1224
NWS STORM PREDICTION CENTER NORMAN OK
0254 PM CDT WED JUL 07 2010

AREAS AFFECTED...SERN NEB...WRN-CENTRAL IA...SRN MN

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 071954Z - 072130Z

MARGINAL HAIL AND DAMAGING WIND THREAT MAY ACCOMPANY STRONGER
MULTICELL STORMS DEVELOPING FROM SERN NEB/WRN IA NWD INTO SRN
MN...BUT A WW DOES NOT APPEAR NECESSARY ATTM. IN ADDITION...HEAVY
RAINFALL MAY ALSO OCCUR WITH THIS ACTIVITY...WITH RATES AOA 1 IN/HR
POSSIBLE.

SURFACE COLD FRONT EXTENDED FROM 20 E OF MSP TO OMA AT 19Z...AND IS
PROVIDING A FOCUS FOR THUNDERSTORM DEVELOPMENT AS MODEST LARGE SCALE
ASCENT ASSOCIATED WITH RRQ OF UPPER MS VALLEY JET...COMBINED WITH
SURFACE HEATING...AIDS IN BOUNDARY LAYER DESTABILIZATION/CINH
REMOVAL. THESE STORMS ARE FORMING WITHIN A GENERALLY WEAK MID-LEVEL
LAPSE RATE ENVIRONMENT...RESULTING IN ONLY MODERATE INSTABILITY
/MLCAPE VALUES AROUND 1000-1500 J PER KG/. IN ADDITION...AREA ALSO
RESIDES ALONG THE SRN FRINGE OF STRONGER SWLY/S LOCATED N OF THE
REGION...WHICH IS YIELDING MARGINAL DEEP LAYER SHEAR FOR ORGANIZED
MULTICELL THUNDERSTORMS. AS A RESULT...THE GENERALLY WEAK
SHEAR/INSTABILITY ENVIRONMENT SHOULD LIMIT ANY SEVERE WEATHER THREAT
ASSOCIATED WITH STRONGER UPDRAFT CORES TO SMALL HAIL AND PERHAPS A
DAMAGING WIND GUST OR TWO.

IN ADDITION TO THE MARGINAL SEVERE WEATHER THREAT...GPS GUIDANCE
INDICATES A PLUME OF PWAT VALUES AOA 2 INCHES MOVING NWD INTO IA.
INTERACTION BETWEEN FRONTAL CIRCULATION AND INFLUX OF
MOISTURE...COMBINED WITH WEAK CAPE/FAVORABLE WARM RAIN PROCESSES
COULD YIELD A ZONE ALONG/AHEAD OF THE FRONT FAVORABLE FOR A
PROLONGED PERIOD OF HEAVY RAINFALL WITH RATES AOA 1 IN/HR.

..GARNER.. 07/07/2010

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

ATTN...WFO...ARX...MPX...DMX...FSD...OAX...

LAT...LON 42229371 40659543 40659621 42789579 43659493 44159355
43749248 42229371

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