MESO: Mesoscale Discussion 1704

ACUS11 KWNS 122101
SWOMCD
SPC MCD 122100
ARZ000-TXZ000-OKZ000-122300-

MESOSCALE DISCUSSION 1704
NWS STORM PREDICTION CENTER NORMAN OK
0400 PM CDT MON AUG 12 2013

AREAS AFFECTED...PORTIONS OF WRN/CNTRL/SRN OK...CNTRL/SRN AR...FAR
NRN TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 122100Z - 122300Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A FEW STORMS COULD BECOME SVR INTO THE LATE AFTERNOON
HOURS AND EVENING HOURS.

DISCUSSION...SFC OBS INDICATE A CONVECTIVELY AUGMENTED BOUNDARY
EXTENDING FROM CNTRL AR WWD INTO SERN OK THAT ALSO ARCS NWWD INTO
NWRN OK. GREATER CONVECTIVE COVERAGE -- AND ATTENDANT STRONGER/MORE
WIDESPREAD COLD POOL ORGANIZATION -- ASSOCIATED WITH A MINOR
MID-LEVEL IMPULSE IS CONTRIBUTING TO MORE NOTABLE SWD/SEWD MOTION OF
THE BOUNDARY FROM SERN OK INTO CNTRL AR...WHILE THE BOUNDARY IS MORE
QUASI-STATIONARY NWWD INTO NWRN OK.

THE AIR MASS HAS BECOME MODERATELY TO STRONGLY UNSTABLE ALONG AND S
OF THE BOUNDARY...AS SFC TEMPERATURES HAVE CLIMBED INTO THE 90S
AMIDST DEWPOINTS IN THE UPPER 60S TO THE LOWER 70S. THIS MAY
CONTRIBUTE TO VIGOROUS UPDRAFTS/DOWNDRAFTS...WITH A FEW STORMS
POTENTIALLY PRODUCING SVR WIND/HAIL ON A SPORADIC BASIS. THE
GREATEST POTENTIAL FOR STRONGER STORMS WOULD EXIST INVOF THE
QUASI-STATIONARY SEGMENT OF THE BOUNDARY FROM CNTRL OK INTO NWRN
OK...WHERE CONVECTION MAY HAVE A LOWER POTENTIAL TO BE UNDERCUT BY
THE BOUNDARY.

HOWEVER...AREA VWP DATA INDICATE THAT STRONGER DEEP SHEAR WILL
REMAIN RELEGATED TO THE COOL SIDE OF THE SFC BOUNDARY...WHERE
RELATIVELY MORE STABLE THERMODYNAMIC PROFILES MAY PRECLUDE
SUSTENANCE OF INTENSE CONVECTION. THE LACK OF OVERLAP OF FAVORABLY
STRONG SHEAR AND BOUNDARY-LAYER BUOYANCY FOR SUSTAINED/ORGANIZED
CONVECTION AMIDST ONLY MODEST MID-LEVEL LAPSE RATES MAY LARGELY
MITIGATE A MORE WIDESPREAD SVR THREAT FROM EVOLVING.

..COHEN/KERR.. 08/12/2013

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

ATTN...WFO...LZK...SHV...TSA...FWD...OUN...

LAT...LON 36659948 35549906 34659867 33839759 33509461 33719219
34239165 34939249 34859438 34999687 36799885 36659948

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