SPC MD 502

MD 0502 CONCERNING TORNADO WATCH 114…117… FOR PORTIONS OF ERN KS…A LARGE PART OF MO…W-CNTRL IL


MESOSCALE DISCUSSION 0502
NWS STORM PREDICTION CENTER NORMAN OK
0602 PM CDT WED APR 17 2013

AREAS AFFECTED...PORTIONS OF ERN KS...A LARGE PART OF MO...W-CNTRL
IL

CONCERNING...TORNADO WATCH 114...117...

VALID 172302Z - 180030Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 114...117...CONTINUES.

SUMMARY...THE SVR THREAT CONTINUES ACROSS REMAINING VALID PORTIONS
OF WW114 AND WW117.

DISCUSSION...THE GREATEST SVR THREAT IN THE NEAR-TERM WILL EXIST
INVOF AN OUTFLOW-REINFORCED FRONT THAT EXTENDS FROM N SIDES OF THE
ST LOUIS AREA TO NEAR COLUMBIA MO...AND THAT ARCS FARTHER W INTO
NERN KS. A CLUSTER OF STORMS OCCASIONALLY EXHIBITING LOW/MID-LEVEL
CIRCULATIONS OVER CNTRL MO WILL ADVANCE NEWD/ENEWD ACROSS PARTS OF
E-CNTRL MO DURING THE NEXT HOUR OR TWO. A RAOB TAKEN AROUND 2040Z
FROM THE UNIVERSITY OF MISSOURI AT COLUMBIA INDICATES THAT A VERY
UNSTABLE AIR MASS RESIDES S OF THE OUTFLOW/FRONT...AND STORMS THAT
INGEST THIS AIR WILL LIKELY REMAIN INTENSE. WITH 225-275 M2/S2 OF
LOW-LEVEL SRH AND STRONG 0-6-KM SHEAR DEPICTED BY THE RAOB...A
THREAT FOR LARGE HAIL...DMGG WINDS...AND POSSIBLY TORNADOES MAY
ACCOMPANY THIS ACTIVITY. HOWEVER...WITH LSX WSR-88D BASE DATA
SUGGESTING THE BOUNDARY OOZING SWD...AND DEEP SHEAR VECTORS ORIENTED
BOUNDARY-PARALLEL...OR WITH A SLIGHT SLY COMPONENT...THIS CONVECTION
MAY HAVE A TENDENCY OF BECOMING UNDERCUT BY SHALLOW COLD AIR
FOLLOWED BY A LESSENING OF THE SVR WIND/TORNADO THREAT.

ELSEWHERE...THE LEADING EDGE OF A POLAR AIR MASS CONTINUES SHIFTING
EWD ACROSS ERN KS. RECENT VISIBLE SATELLITE IMAGES INDICATE
CONVECTIVE TOWERS DEEPENING ALONG AND AHEAD OF THE FRONT ACROSS
PARTS OF ERN KS INTO FAR WRN MO. STORMS THAT EVOLVE AHEAD OF THE
FRONT WILL HAVE THE GREATEST POTENTIAL FOR ALL SVR MODES...WHILE
ACTIVITY FARTHER W MAY POSE A MARGINAL SVR HAIL.

..COHEN.. 04/17/2013

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

ATTN...WFO...ILX...LSX...SGF...EAX...TSA...TOP...ICT...

LAT...LON   37199659 38459604 39639471 40059255 40009122 39369024
            38349064 36829266 36559417 36979475 37199659

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md0502.html