SPC MD 1811

MD 1811 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR NRN OK…SRN KS


MESOSCALE DISCUSSION 1811
NWS STORM PREDICTION CENTER NORMAN OK
0205 PM CDT SAT AUG 25 2012

AREAS AFFECTED...NRN OK...SRN KS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 251905Z - 252030Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THREAT FOR MARGINALLY SVR HAIL AND STRONG THUNDERSTORM
WIND GUSTS WILL EXIST THIS AFTERNOON OVER NRN OK AND SRN KS...BUT AN
ORGANIZED SVR THUNDERSTORM EVENT IS NOT EXPECTED AND A WW IS
UNLIKELY. IN ADDITION...TRAINING THUNDERSTORMS MAY DEVELOP OVER THE
AREA LATER THIS AFTERNOON AND EVENING...AND WOULD POSE A THREAT FOR
LOCALLY HEAVY RAINFALL.

DISCUSSION...MESOANALYSIS AT 1845Z SHOWS POCKETS OF CLEARING AND
STRONGER SURFACE HEATING OCCURRING OVER NRN OK AND SRN KS...WHICH IS
AIDING IN LOCALLY BOOSTING TEMPERATURES INTO THE UPR 80S. IN
ADDITION...VERY MOIST LOW-LEVEL AIRMASS RESIDES ACROSS THE
REGION...WITH DEWPOINTS IN THE UPR 60S TO LOW 70S...AND PWAT VALUES
FROM 1.75-2.0 INCHES. THOUGH MIDLEVEL LAPSE RATES ARE NOT
PARTICULARLY STEEP...THE WARM/MOIST BOUNDARY LAYER AIRMASS IS
YIELDING MLCAPE VALUES NEAR 1500 J/KG. THE FAVORABLE THERMODYNAMIC
ENVIRONMENT...IN ADDITION TO WEAK LOW-LEVEL CONVERGENCE AND ASCENT
AHEAD OF AN UPPER-LEVEL TROUGH IS LEADING TO ISOLATED/SCATTERED
THUNDERSTORM DEVELOPMENT OVER NRN OK AND SRN KS. WEAK DEEP-LAYER
VERTICAL WIND SHEAR /0-6 KM BULK SHEAR FROM 15-20 KT/ WILL GENERALLY
PRECLUDE ORGANIZED SVR THUNDERSTORM DEVELOPMENT THIS AFTERNOON...BUT
A FEW MULTICELLS MAY BRIEFLY BECOME CAPABLE OF PRODUCING HAIL NEAR 1
INCH IN DIAMETER...AS WELL AS STRONG WIND GUSTS.

IN ADDITION...SHORT-TERM MODEL GUIDANCE SUGGESTS THUNDERSTORMS MAY
TRAIN NEWD ACROSS THE AREA BY LATE AFTERNOON INTO THE EVENING. GIVEN
THE HIGH PWAT VALUES AND TALL SKINNY CAPE PROFILES...LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE.

..GARNER/WEISS.. 08/25/2012

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

ATTN...WFO...TSA...ICT...OUN...DDC...

LAT...LON   36829578 35889749 35539859 35809942 36559971 37879790
            38169666 37729558 36829578

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