SPC MD 1990

MD 1990 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR SOUTHERN MO/NORTHERN AR INTO NORTHWEST TN/WESTERN KY/SOUTHERN IL


MESOSCALE DISCUSSION 1990
NWS STORM PREDICTION CENTER NORMAN OK
0126 PM CDT WED SEP 26 2012

AREAS AFFECTED...SOUTHERN MO/NORTHERN AR INTO NORTHWEST TN/WESTERN
KY/SOUTHERN IL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 261826Z - 262000Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...TSTMS ARE EXPECTED TO CONTINUE TO INCREASE ACROSS SOUTHERN
MO/NORTHERN AR INTO SOUTHERN IL/WESTERN KY/NORTHWEST TN THROUGH
MID/LATE AFTERNOON...WITH THE STRONGEST TSTMS CAPABLE OF DAMAGING
WINDS/SEVERE HAIL. WHILE A WATCH IS NOT
IMMINENT/CERTAIN...DEVELOPMENTAL TRENDS WILL BE MONITORED FOR A
POSSIBLE SEVERE TSTM WATCH.

DISCUSSION...AHEAD OF A CLUSTER OF SHOWERS/FEW TSTMS ACROSS
NORTHEAST OK/FAR SOUTHWEST MO AS OF MIDDAY...STRONGER CELLULAR
CONVECTION HAS RECENTLY /SINCE 1730Z/ INCREASED ACROSS FAR SOUTHERN
MO/NORTHWEST AR/FAR NORTHEAST OK. THIS APPEARS TO BE OCCURRING IN
VICINITY OF A REMNANT EARLY DAY OUTFLOW BOUNDARY ACROSS SOUTHERN MO.
HEATING/DESTABILIZING AIRMASS ASIDE...THIS DEVELOPMENT APPEARS TO BE
FURTHER AIDED BY AN EASTWARD-MOVING SHORTWAVE TROUGH/POSSIBLE MCV
ACROSS SOUTHEAST KS/NORTHEAST OK. WHILE EXISTING CLOUD COVER
/ESPECIALLY ACROSS SOUTHERN MO/ WILL BE AT LEAST SOMEWHAT HINDER THE
DEGREE OF HEATING AND DESTABILIZATION...DEVELOPMENT OF 1000-2000
J/KG MLCAPE WILL ACCOUNT FOR SOME STRONGER/SUSTAINED UPDRAFTS THIS
AFTERNOON.

THIS IS ESPECIALLY THE CASE GIVEN THAT SOMEWHAT ENHANCED MID
TROPOSPHERIC FLOW...LIKELY ASSOCIATED WITH THE AFOREMENTIONED
MID-LEVEL IMPULSE...WILL SPREAD EASTWARD ACROSS THE REGION. RECENT
WSR-88D VWP DATA FROM TULSA WSR-88D IS INDICATIVE OF 40+ 0-6 KM
SHEAR. THIS MAY PROVE SUFFICIENT FOR SOME SEMI-ORGANIZED STRUCTURES
INCLUDING SOME MARGINAL SUPERCELL STRUCTURES...AND EVENTUALLY SMALL
BOWING SEGMENTS AS UPSCALE GROWTH MAY GRADUALLY OCCUR. WHILE THE
OVERALL SCOPE OF THE SEVERE THREAT IS A BIT UNCERTAIN IN THE SHORT
TERM...DAMAGING WINDS/SEVERE HAIL WILL BE POSSIBLE AT LEAST ON AN
ISOLATED BASIS THIS AFTERNOON.

..GUYER/MEAD.. 09/26/2012

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

ATTN...WFO...PAH...MEG...LSX...LZK...SGF...TSA...

LAT...LON   37279215 37579058 38138833 37778765 36468847 35609012
            35299427 36709312 37279215

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md1990.html