Flash Flood and Damaging Winds in Illinois, April 21, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
200 PM CDT SAT APR 21 2002

MODELS AGAIN IN VERY GOOD AGREEMENT AND CONSISTENT WITH PREVIOUS
RUNS. ONE DIFFERENCE SEEN IS ETA TRACKING SFC LOW LITTLE MORE
NORTHEAST THAN DUE EAST...THAN IN PREV FCST. WILL FOLLOW
ETA/MESOETA...WHICH HAS BEEN THE CASE.

NO PCPN IN AREA EXCEPT FOR SRN IL. BOX ONLY FOR SERN 6 COUNTIES TIL
4PM. SFC LOW RIGHT OVER STL...AS FCST BY MODELS WITH WARM FRONT
STRETCHING EASTWARD INTO SWRN IND AND NRN KY. TRWS DEVELOPING ALONG
CF STRETCHING FROM LOW INTO SCNTRL MO. THESE STORMS MOVING NE AND
WILL REACH SERN IL THIS AFTERNOON AND INTO EARLY EVENING. INVERTED
TROF INTO ERN IA FROM LOW PRODUCING LIGHT PCPN AT THIS TIME...AND
WITH AIRMASS ALREADY WORKED OVER IN CNTRL IL AND LOTS OF LOW
CLOUDS...WILL ONLY GO WITH CHC OF PCPN EARLY IN REMAINDER OF CWA.
CLEAR HOLE IN SWRN IL PLAYING HAVOC WITH TEMPS AND COULD PUSH
INSTABILITY LITTLE FURTHER NORTH. MAY HAVE TO INCLUDE FEW COUNTIES
NORTH OF BOX WITH PCPN FOR THIS EVENING. WILL MAKE FINAL GROUPING
ADJUSTMENTS CLOSER TO ISSUANCE TIME. WINDS WILL ALSO SWITCH AROUND
TO WEST OR NW TONIGHT.

FLOOD WATCH STATUS...CONTINUES UNTIL 7PM. SYSTEM WILL BE SOUTHEAST
OF AREA BY THEN AND MOST OF PCPN WILL BE GONE. THEREFORE WILL
LIKELY NOT CONTINUE WATCH INTO THIS EVENING.

CLOUDS WILL BE VERY SLOW TO CLEAR TOMORROW. MODELS HANG ON TO LOW
LEVEL MOISTURE DURING DAY AND CU RULE CONTS WITH BKN CLOUDS. WILL
CONT CRNT FCST TRENDS OF BECOMING PARTLY SUNNY TOM.

REMAINDER OF SHORT TERM WILL BE QUITE WITH COOL HIGH PRESSURE
BUILDING IN TONIGHT AND CONTINUING THROUGH TUE.

WILL CONTINUE WITH RW/TRW ON WED AND UPGRADE CHANCES TO LIKELY ACRS
AREA. FRONT COMES THROUGH CWA AROUND 18Z WITH LOTS OF MOISTURE AND
DYNAMICS. BELIEVE AVN TOO FAST WITH THIS FRONT AND WILL FOLLOW
SLOWER ETA.

REMAINDER OF EXTENDED: WILL KEEP THUR AND FRI DRY AS ANOTHER AREA
OF HI PRSS BUILDS IN WITH SLIGHTLY COOLER TEMPS. THEN ANOTHER CHC OF
RW/TRW NEXT SAT. THEN DRY ON SUNDAY.

MAV GUIDANCE TEMPS LOOK GOOD AND CONTS TO AGREE WITH CRNT FCST...SO
WILL FOLLOW FOR NOW.

SPI EB 037/056 035/067 050 77300
PIA EB 036/054 034/066 049 77300
DEC EB 037/055 035/067 050 77300
CMI EB 036/054 034/065 049 77300
MTO EB 038/056 036/066 050 77600
LWV EB 042/058 037/068 051 77700

.ILX...NONE.

AUTEN

ILZ027>031-036>038-040>057-061>063-066>068-071>073-211715-

HAZARDOUS WEATHER OUTLOOK FOR CENTRAL ILLINOIS
NATIONAL WEATHER SERVICE LINCOLN IL
1100 AM CDT SUN APR 21 2002

...FLOOD WATCH IS IN EFFECT THIS AFTERNOON FOR CENTRAL AND SOUTHEAST
ILLINOIS...
...SLIGHT RISK OF SEVERE WEATHER ALONG AND SOUTH OF I-72 INTO EARLY
EVENING...

HEAVY RAIN WILL CONTINUE TO THREATEN CENTRAL AND SOUTHEAST ILLINOIS
THIS AFTERNOON AS LOW PRESSURE MOVES INTO SOUTHERN ILLINOIS AND
LIFTS A WARM FRONT NORTH TOWARD I-70. THE LOW WILL PASS EAST OF
ILLINOIS BY SUNSET...ENDING THE HEAVY RAIN THREAT. IN ADDITION...THERE
IS A SLIGHT RISK OF SEVERE STORMS SOUTH OF I-72. THE MAIN SEVERE
WEATHER THREAT WILL BE LARGE HAIL AND DAMAGING WINDS ESPECIALLY FROM
I-70 SOUTH UNTIL SUNSET.

PLAHMER/KH