Severe Thunderstorm Warning 164, NWS St. Louis, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
252 PM CDT FRI JUN 11 1999

KSGF 88D LIT UP AGAIN WITH CLUSTERS OF TSTMS THIS AFTN.  VISIBLE
IMAGERY SHOWS SEVERAL OUTFLOW BOUNDARIES INTERACTING TO FOCUS
CONVECTION.  SURFACE ANALYSIS SHOWS AN ILL DEFINED FRONTAL BOUNDARY
FROM IOWA INTO CEN KS.

LITTLE DIFFERENCES IN MODELS AS THE CWFA REMAINS UNDER WEAK FLOW
ALOFT. CWFA WILL REMAIN ON WRN PERIPHERY OF A BROAD RIDGE COVERING
THE ERN U.S. INTO SAT.  FLOW ARND THIS RIDGE WILL TRANSPORT DEEP
LAYER OF SUBTROPICAL MOISTURE INTO THE AREA.  THE WEAK FRONTAL
BOUNDARY WILL LOSE ITS IDENITY AS IT SINKS INTO THE SWRN MO SAT.
MODELS INDICATE 850 MB FLOW SHIFTING TO THE NE BEHIND THE BOUNDARY
BUT LITTLE CHANGE IN THE MOIST AIRMASS.  MODELS SUGGEST GOOD 850 MB
MOISTURE CONVERGENCE AND THETA-E ADVECTION INTO SC MO ALONG THE
BOUNDARY SAT AFTN/NGT. MOST ACTIVITY WILL DIURNALLY DRIVEN BUT SOME
ACTIVITY WILL LINGER DURING THE NGT AS REMNANTS OF THE FRONT PARK
OVER THE AREA. WITH WEAK STEERING CURRENTS...LOCALIZED VERY HEAVY
RAINFALL AMOUNTS AND FLOODING WILL BE POSSIBLE.

IN THE EXTENDED...LITTLE CHANGE IN PATTERN THROUGH MON. UPPER FLOW
BEGINS TO TURN MORE WLY BY TUE WHICH WILL RESULT IN DECREASE OF
DIURNAL CONVECTION.

(PRELIMINARY CCF FOR COORDINATION PURPOSES ONLY)

CCF
SGF EE 065/081 063/080 063 115444
JLN EE 065/082 064/081 063 113333
UNO EE 067/084 066/083 064 115444
VIH EE 065/080 064/080 063 114444

FOSTERT

ILZ058>060-064-065-069-070-074-079-095>102-MOZ009-010-018-019-026-
027-034>036-041-042-047>052-059>065-072>075-084-085-099-120100-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
258 PM CDT FRI JUN 11 1999

SCATTERED THUNDERSTORMS CAN BE EXPECTED ACROSS THE ENTIRE AREA
THROUGH THE AFTERNOON AND EARLY EVENING HOURS.  A FEW OF THE STORMS
MAY BE SEVERE PRODUCING DAMAGING DOWNBURST WINDS OF 60 MPH AND HAIL
TO ONE INCH IN DIAMETER.  THE THUNDERSTORM ACTIVITY SHOULD END NEAR
SUNSET.

LOCALLIZED SKYWARN ACTIVATION MAY BE NEEDED THE REMAINDER OF
THIS AFTERNOON AND THIS EVENING.

THIS OUTLOOK COVERS THE COUNTY WARNING AREA OF THE NWS OFFICE
IN ST. LOUIS. AREAS INCLUDED ARE PARTS OF CENTRAL...NORTHEAST AND
EAST CENTRAL MISSOURI...AND SOUTHWEST ILLINOIS.

GLASS

ILZ058>060-064-065-069-070-074-079-095>102-MOZ009-010-018-019-026-
027-034>036-041-042-047>052-059>065-072>075-084-085-099-120100-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
258 PM CDT FRI JUN 11 1999

SCATTERED THUNDERSTORMS CAN BE EXPECTED ACROSS THE ENTIRE AREA
THROUGH THE AFTERNOON AND EARLY EVENING HOURS.  A FEW OF THE STORMS
MAY BE SEVERE PRODUCING DAMAGING DOWNBURST WINDS OF 60 MPH AND HAIL
TO ONE INCH IN DIAMETER.  THE THUNDERSTORM ACTIVITY SHOULD END NEAR
SUNSET.

LOCALLIZED SKYWARN ACTIVATION MAY BE NEEDED THE REMAINDER OF
THIS AFTERNOON AND THIS EVENING.

THIS OUTLOOK COVERS THE COUNTY WARNING AREA OF THE NWS OFFICE
IN ST. LOUIS. AREAS INCLUDED ARE PARTS OF CENTRAL...NORTHEAST AND
EAST CENTRAL MISSOURI...AND SOUTHWEST ILLINOIS.

GLASS