Severe Thunderstorm Warning 157, NWS St. Louis, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
337 AM CDT FRI JUN 11 1999

THE LATEST SFC ANALYSIS INDICATES A SFC LOW LOCATED OVR IOWA WITH A
COLD FRONT EXTENDING ACROSS KANSAS. I AGREE WITH THE SPC DAY 1
OUTLOOK OF PLACING THE MAIN THREATS OF SVR WEATHER AHEAD OF THE
DRYLINE..NEAR THE 850 THETA E RIDGE OVR WEST TEXAS AND WRN
KANSAS...AND NEAR THE SFC LOW LOCATED IN IOWA.

FOR OUR FORECAST AREA...DETERMINING WHERE THUNDERSTORMS WILL
FORM WILL NOT BE AS CLEAR CUT AS IN THOSE AREAS.  THIS PRESENTS THE
FORECAST PROBLEM OF THE DAY.  CAPES OF 500-1500 J/KG ACROSS THE AREA
LATER TODAY AND ABUNDANT LOW LVL MSTR WILL ALLOW SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG BOUNDARIES FROM PREVIOUS
CONVECTION...AS WELL AS NEAR THERMAL BOUNDARIES SET UP BY
DIFFERENTIAL HEATING CAUSED BY VARYING AMOUNTS OF CLOUD COVER.  200
MB COUPLED JETS SOUTHWEST OF OUR FORECAST AREA OVER OKLAHOMA COULD
PROVIDE SUFFICIENT UPPER SUPPORT TO AID IN SCATTERED CONVECTION OVR
AREAS SOUTHWEST OF OUR FORECAST. WITH SOUTHWEST UPPER FLOW...SOME OF
THESE THUNDERSTORMS COULD ALSO MOVE INTO OUR AREA.  THE WEAK WIND
FIELD WILL SUPPORT SLOWER MOVING STORMS. THUS...SOME LOCATIONS
ACROSS THE FORECAST AREA COULD RECEIVE HEAVY RAIN AND LOCALIZED
FLOODING WITH STRONGER STORMS THAT DEVELOP LATER THIS AFTERNOON.

AS THE COLD FRONT APPROACHES OUR AREA THIS WEEKEND...MORE ORGANIZED
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS IS EXPECTED...THUS I AGREE
WITH THE INCREASING POPS INDICATED IN BOTH THE FWC AND FAN GUIDANCE.
MY PREFERRED MODEL WAS THE ETA.

(PRELIMINARY CCF FOR COORDINATION PURPOSES ONLY)

CCF
SGF EE 083/065 080/062 081 103444
JLN EE 083/065 080/063 082 103444
UNO BE 088/070 08T5/066 085 103333
VIH BE 086/068 082/064 083 103344

VESPER