SPC MD 991

MD 0991 CONCERNING SEVERE THUNDERSTORM WATCH 325…326… FOR OK…SERN KS…SWRN MO…NWRN AR


MESOSCALE DISCUSSION 0991
NWS STORM PREDICTION CENTER NORMAN OK
1121 PM CDT WED MAY 30 2012

AREAS AFFECTED...OK...SERN KS...SWRN MO...NWRN AR

CONCERNING...SEVERE THUNDERSTORM WATCH 325...326...

VALID 310421Z - 310615Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
325...326...CONTINUES.

SUMMARY...A THREAT OF DAMAGING WIND GUSTS AND MARGINAL HAIL REMAIN
POSSIBLE AREA-WIDE...BUT THE THREAT MAY BE DECREASING OVER WRN
AREAS.

DISCUSSION...CURIOUSLY...THE RAP BASED OBJECTIVE ANALYSIS HAS
STUBBORNLY KEPT A VERY STRONG AXIS OF INSTABILITY OVER THE ERN TX
PANHANDLE INTO WRN OK THIS EVENING...DESPITE HOURS OF COOL AND DRY
SURFACE OBSERVATIONS FROM EARLIER OUTFLOW. MODIFYING THE CDS
SOUNDING FOR CURRENT CONDITIONS YIELDS PERHAPS 100 J/KG
SBCAPE...WHILE THE RAP MODEL SUGGESTS THERE SHOULD BE 2500 J/KG.

DEWPOINTS ARE MIXING INTO THE UPPER 40S AND LOWER 50S OVER MUCH OF
THIS AREA. THESE OBSERVATIONS BLEND WELL WITH CURRENT RADAR TRENDS
WHICH SHOW WEAKENING OF THE CONVECTION OVER NWRN OK.

SURFACE ANALYSIS AND THE 00Z NORMAN SOUNDING DO INDICATE THERE IS
MORE SUBSTANTIAL MOISTURE PRESENT OVER CNTRL AND ERN OK...WITH
DEWPOINTS IN THE LOWER TO MIDDLE 60S F. THIS WOULD APPEAR TO BE THE
MOST LIKELY AREA FOR SEVERE STORMS...AS THE OUTFLOW CONTINUES SWD
ACROSS THE STATE. NEW CELLS MAY DEVELOP...AND GUSTY WINDS AND
MARGINALLY SEVERE HAIL WILL BE POSSIBLE. THE HIGHEST THREAT AREA
OVERALL IS FROM CNTRL OK INTO NERN OK WHERE MORE VIGOROUS CELLS ARE
KEEPING UP WITH THE GUST FRONT. FOR AREAS FROM WRN OK INTO THE TX
PANHANDLE...THERE IS LITTLE ADDITIONAL ACTIVITY BEING GENERATED
BEHIND THE ADVANCING OUTFLOW...WHICH WILL LIKELY RESULT IN A GRADUAL
WEAKENING OF THESE WINDS IF NEW STORMS DO NOT DEVELOP.

..JEWELL/CORFIDI.. 05/31/2012

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

ATTN...WFO...SGF...TSA...ICT...OUN...

LAT...LON   35459482 34789736 34789820 34919847 35159861 35459815
            35969729 36369636 36909547 37219496 37149417 36719344
            36039348 35459482

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md0991.html