SPC MD 698

MD 0698 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR NRN…CNTRL…AND SRN OK


MESOSCALE DISCUSSION 0698
NWS STORM PREDICTION CENTER NORMAN OK
0145 PM CDT SUN MAY 19 2013

AREAS AFFECTED...NRN...CNTRL...AND SRN OK

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 191845Z - 191945Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...TSTM INITIATION APPEARS INCREASINGLY PROBABLE OVER THE
NEXT 1-2 HRS ACROSS NRN/CNTRL OK. STORMS SHOULD QUICKLY INTENSIFY
AND POSE A THREAT FOR VERY LARGE HAIL...DMGG WINDS...AND A FEW
TORNADOES. A TORNADO WATCH WILL LIKELY BE NEEDED IN THE NEXT HOUR OR
SO.

DISCUSSION...SFC ANALYSIS FROM 18Z SHOWS A DRYLINE RAPIDLY MIXING
EWD ACROSS WRN OK...ATTENDANT TO A DEEPENING SFC LOW OVER NWRN
OK...WITH UPPER 60S TO LOWER 70S F DEWPOINTS WIDESPREAD ACROSS CNTRL
OK. A REMNANT OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION REMAINS
DRAPED ACROSS FAR NRN OK...BUT UNIFORM SLY WINDS WERE NOTED ON BOTH
SIDES OF THIS BOUNDARY. MEANWHILE...AN INCREASINGLY AGITATED LINE OF
CU WAS NOTED PRECEDING THE DRYLINE...ORIENTED SW-NE FROM NEAR A 30 E
CSM TO 15 NW END LINE...WITHIN A ZONE OF WEAK LOW-LEVEL CONVERGENCE.
THIS AREA APPEARS TO BE THE MOST LIKELY FOCUS FOR INITIAL CONVECTIVE
DEVELOPMENT THIS AFTERNOON...AS A PROGRESSIVE UPPER IMPULSE
CURRENTLY POSITIONED OVER THE OK AND NRN TX PANHANDLES SHOULD
CONTINUE EWD NEAR THE OK/KS BORDER.

STRONG SFC HEATING IS UNDERWAY ACROSS MOST OF OK...WITH BOUNDARY
LAYER CU FORMING MORE RECENTLY BUT STILL EXHIBITING CAPPED/FLAT
CHARACTER. PERSISTENT CONVERGENCE ALONG THE DRYLINE...ALONG WITH
FURTHER BOUNDARY LAYER HEATING WITH TEMPERATURES REACHING THE UPPER
80S/LOWER 90S F WITHIN THE MOIST AIR...SHOULD RESULT IN EROSION OF
THE SIGNIFICANT CAPPING INVERSION NOTED IN THE 18Z OUN SOUNDING. AS
THIS OCCURS...DISCRETE TSTM DEVELOPMENT ALONG THE DRYLINE APPEARS
LIKELY...WITH AN ACCOMPANYING THREAT FOR LARGE HAIL AND DMGG WINDS.
TORNADO POTENTIAL SHOULD STEADILY INCREASE THROUGH THE LATE
AFTERNOON/EVENING ACCOMPANYING SUSTAINED SUPERCELLS...AS WIND
PROFILES CONTINUE TO STRENGTHEN.

RECENT SUITE OF HIGH-RESOLUTION MODEL GUIDANCE INDICATES CONVECTION
SHOULD INITIATE ACROSS THE NRN HALF OF THE HIGHLIGHTED AREA BETWEEN
20-21Z...AND PERHAPS AFTER 21Z ACROSS SWRN/S-CNTRL OK. A TORNADO
WATCH WILL LIKELY BE ISSUED WITHIN THE NEXT HOUR.

..ROGERS/KERR.. 05/19/2013

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

ATTN...WFO...TSA...OUN...

LAT...LON   36889595 36339551 35369631 34689650 34089664 34039693
            34159782 34259839 35169859 35709863 36119865 36579845
            36789840 36789713 36889595

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md0698.html