SPC MD 1874

MD 1874 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PART OF ERN KS THROUGH EXTREME NERN OK


MESOSCALE DISCUSSION 1874
NWS STORM PREDICTION CENTER NORMAN OK
0513 PM CDT MON SEP 03 2012

AREAS AFFECTED...PART OF ERN KS THROUGH EXTREME NERN OK

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 032213Z - 040015Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...WIDELY SCATTERED SHOWERS AND THUNDERSTORMS MIGHT BECOME
CAPABLE OF PRODUCING A FEW DOWNBURSTS OVER A PORTION OF ERN KS AND
EXTREME NERN OK THROUGH EARLY EVENING. COVERAGE OF ANY SEVERE EVENTS
IS EXPECTED TO REMAIN SPARSE...AND A WW IS NOT ANTICIPATED.

DISCUSSION...EARLY THIS EVENING THE BOUNDARY LAYER OVER SERN KS HAS
MIXED OUT TO THE SOUTH OF A QUASISTATIONARY FRONT WHERE TEMPERATURES
HAVE WARMED INTO THE LOW 100S AND DEWPOINTS HAVE DROPPED INTO THE
50S. WARM AIR ALOFT /-7C AT 500 MB/ AND MODEST LOW LEVEL MOISTURE
YIELD MARGINAL INSTABILITY WITH MLCAPE AOB 800 J/KG WHICH SHOULD
LIMIT DEGREE OF PRECIPITATION LOADING IN UPDRAFTS.
NEVERTHELESS...STEEP LOW LEVEL LAPSE RATES WITHIN THE DEEPLY MIXED
BOUNDARY LAYERS WILL PROMOTE A THREAT OF ISOLATED WIND DAMAGE WITH
DEVELOPING CONVECTION.

THE ATMOSPHERE IS MORE UNSTABLE ALONG AND EAST OF THE BOUNDARY
ACROSS EXTREME ERN KS INTO WRN MO...BUT LACK OF CUMULUS DEVELOPMENT
SUGGESTS THE BOUNDARY LAYER IS CAPPED WHICH IS ALSO REFLECTED ON
PFCS FROM THE RAPID REFRESH MODEL. THUS STORMS WILL PROBABLY WEAKEN
AS THEY ATTEMPT TO MOVE FARTHER EAST INTO THE AXIS OF STRONGER
INSTABILITY...ESPECIALLY GIVEN APPARENT WEAK MESOSCALE FORCING.

..DIAL/MEAD.. 09/03/2012

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

ATTN...WFO...SGF...TSA...TOP...ICT...

LAT...LON   37709491 36919493 36829605 37499646 38359651 38809635
            38649554 37709491

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md1874.html