Flash Flooding in Illinois, May 28, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
100 PM CDT TUE MAY 28 2002

12Z AVN JUST IN AND RELATIVELY CLOSE TO 12Z ETA WHICH BOTH MODELS
ARE SLOWER WITH PACIFIC FRONT NOT MOVING EAST THRU CENTRAL IL UNTIL
MIDNIGHT THU NIGHT. WILL CONTINUE CHANCE POPS OF CONVECTION THRU THU
EVENING WITH ENHANCED CHANCES DURING AFTERNOON AND EVENING AS WE
CONTINUE TO BE IN THE SAME WEATHER PATTERN THAT STARTED MON. DRIER
WEATHER RETURNS LATE THIS WEEK WITH ANOTHER CHANCE OF CONVECTION
EARLY NEXT WEEK.

17Z SURFACE ANALYSIS AS WARM FRONT ALONG I-74 WITH DEWPOINTS IN MID
TO UPPER 60S...EVEN MORE HUMID THAN YESTERDAY. WARM TEMPS 75 TO 82.
UNSTABLE ATMOSPHERE AGAIN WITH LIFTED INDICES OF MINUS 5 TO 6 ACROSS
CWA.

SCATTERED CONVECTION SHOULD AGAIN DEVELOP DURING THIS AFTERNOON
AND CONTINUE TONIGHT ESPECIALLY THIS EVENING. BOUNDARY THAT WAS
BETWEEN I-70 AND I-72 YESTERDAY IS CLOSER TO I-74 AT 17Z SO
CONVECTION SHOULD BE FOCUSED NEAR IT...SO A BIT FURTHER NORTH THAN
MON. WILL MENTION LOCALLY HEAVY RAIN TONIGHT AS MID/UPPER LEVEL
STEERING WINDS WEAK...SW 5-15 KTS AT 700 AND 500 MB AS SUMMER TIME
PATTERN PREVAILS. ENHANCED ALSO BY WEAK SHORT WAVE ENERGY EJECTING
OUT OF CENTRAL PLAINS TOWARD CENTRAL IL. ISOLATED SVR AND LOCALIZED
FLOODING POSSIBLE N OF I-70 THRU THIS EVENING LIKE MON...JUST
FURTHER NORTH.

LITTLE CHANGE WED AND THU WITH ENHANCE DIURNALLY DRIVEN CONVECTION
IN AFTERNOON AND EVENING. BOUNDARY SHOULD LIFT NORTH OF CWA WED BUT
STILL WEAK SHORT WAVE ENERGY TO INTERACT WITH UNSTABLE ATMOSPHERE TO
DEVELOP CONVECTION. NO SLIGHT RISK BUT ISOLATED SVR WITH LOCALIZED
FLOODING STILL POSSIBLE THRU THU EVENING. GUIDANCE TEMPS SIMILAR AND
FOLLOWED WITH LOWS IN THE LOW TO MID 60S AND HIGHS 80 TO 85 THRU
THU. PACIFIC COLD FRONT MOVES EAST ACROSS IL THU EVENING...EXITING
EAST OF IL AROUND 06Z/FRI.

FAIRLY ACTIVE SPLIT UPPER LEVEL FLOW THRU THU SHIFTS LATE THIS WEEK
WITH STRONG UPPER LEVEL RIDGE OVER CO AND IL IN A NW FLOW ALOFT.
DRIER/LESS HUMID AND SOMEWHAT COOLER AIR STILL LOOKS TO ARRIVE FRI
AND SAT. MOST EXTENDED MODELS STILL SHOWING MCS ACTIVITY MOVING ESE
FROM THE NORTHERN PLAINS INTO CENTRAL IL SAT NIGHT THRU TUE.

...PRELIMINARY CCF FOR COORDINATION PURPOSES...

SPI EE 063/082 063/083 063 07443
PIA EE 063/081 063/082 062 07544
DEC EE 063/082 063/083 063 07443
CMI EE 062/081 062/082 063 07544
MTO EE 063/082 064/083 064 07443
LWV EE 066/083 066/085 065 07343

.ILX...NONE.

KH

ILZ027>031-036>038-040>057-061>063-066>068-071>073-281800-

HAZARDOUS WEATHER OUTLOOK FOR CENTRAL ILLINOIS
NATIONAL WEATHER SERVICE LINCOLN IL
1205 PM CDT TUE MAY 28 2002

SCATTERED STORMS OVER NORTHEASTERN MISSOURI WILL CONTINUE TO MOVE
EAST INTO CENTRAL ILLINOIS THIS AFTERNOON. A STATIONARY FRONT OVER
THE AREA WILL INTERACT WITH A WARM AND UNSTABLE AIRMASS TO THE
SOUTH...TO PRODUCE ADDITIONAL THUNDERSTORMS THIS AFTERNOON AND INTO
THIS EVENING. SOME OF THESE STORMS COULD CONTAIN SMALL HAIL...GUSTY
WINDS...INTENSE LIGHTNING AND LOCALLY HEAVY RAINFALL.

AUTEN