Flash Flooding and Hail in Illinois, May 27, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
100 PM CDT MON MAY 27 2002

MODELS DIFFER WITH HANDLING SHORT WAVES EJECTING FROM THE CENTRAL
PLAINS INTO CENTRAL IL THRU THU WITH A WARM AND UNSETTLED WEATHER
PATTERN PREVAILING. FAIRLY ACTIVE SPLIT ZONAL FLOW PREVAILS INTO THU
WITH JET STREAM ACROSS THE NORTHERN TIER STATES WHILE WEAK CUTOFF
UPPER LEVEL LOW OVER THE SOUTHERN PLAINS STATES. TENDING TO LEAN
WITH THE ETA MODEL WHICH BETTER HANDLES MESOSCALE FEATURE AND LESS
CONVECTIVE FEEDBACK THAN AVN.

WATER VAPOR LOOP SHOWING MCV NEAR KUIN WITH CONVECTION AS FAR EAST
AS A GALESBURG TO PITTSFIELD LINE AND MOVING SLOWLY NE. SURFACE
ANALYSIS HAS ONE FRONTAL BOUNDARY EXTENDING FROM CENTRAL WI THRU FAR
S MN SW TO 1009 MB LOW OVER EAST KS. A SECONDARY WARM FRONT LIFTING
N NEAR I-70 WHERE ISOLATED CONVECTION DEVELOPNG. WARMER AND MORE
HUMID TODAY WITH TEMPS 75 TO 81 EXCEPT RAIN COOLED 64 TO 70 FROM
GALESBURG TO QUINCY. SOUTH WINDS 5 TO 10 MPH ADVECTED HIGH DEWPOINTS
IN THE LOW TO MID 60S WHILE FROM KCMI NE NEAR 55. SKIES HAVE BECOME
PARTLY TO MOSTLY CLOUDY.

MORE UNSTABLE ATMOSPHERE WITH LIFTED INDICES MINUS 4-7C SW OF KBMI
TO KHUF AND WILL HAVE SCATTERED CONVECTION ACROSS CWA EVEN SE
TONIGHT. ISOLATED SVR POSSIBLE PER SPC THRU SUNSET WITH WEAK TO
MODERATE SHEAR AND CAPES 1000-2000 J/KG AS DEWPOINTS GOT HIGHER
TODAY THAN EARLIER EXPECTED.

WILL CONTINUE CHANCE OF CONVECTION TONIGHT THRU THU ACROSS CENTRAL
IL WITH FRONTAL BOUNDARY LINGERING IN AREA AND SERIES OF SHORT WAVES
EJECTING TOWARD IL FROM THE CENTRAL PLAINS. BEST CHANCE TONIGHT THRU
TUE NIGHT. SURPRISED TO SEE EXTENDED ETA DRY OUT WED NIGHT AND THU.
WILL HOLD ONTO GOOD CHANCE OF CONVECTION UNTIL PACIFIC COOL FRONT
PASSES THRU BY THU EVENING. GUIDANCE FAIRLY SIMILAR WITH TEMPS WITH
MAV A BIT COOLER THAN FWC AND MESOETA 2M TEMPS INBETWEEN WHICH WILL
FOLLOW AND CURRENT FORECAST REFLECTS.

EXTENDED MODELS STILL SHOWING NW UPPER LEVEL FLOW EVOVLING LATE THIS
WEEK WITH 590 DM 500 MB RIDGE NEAR CO. GENERALLY DRY AND A BIT COOLER
WEATHER FRI/SAT FOR CENTRAL IL WITH MORE OF A COOL DOWN ACROSS THE
GREAT LAKES AND NEW ENGLAND. MCS ACTIVITY FROM DEVELOPING WAA WITH LOW
PRESSURE IN THE CENTRAL PLAINS TO MOVE ESE INTO THE MID MS VALLEY
SAT NIGHT THRU MON WITH NEXT CHANCE OF CONVECTION OVER CWA. AREAS
FROM KSPI TO KHUF SOUTH COULD EVEN HAVE CONVECTION AS EARLY AS SAT
BUT WILL LEAVE IT DRY FOR NOW.

...PRELIMINARY CCF FOR COORDINATION PURPOSES...

SPI EE 063/081 063/082 062 07554
PIA EE 061/081 062/083 061 07543
DEC EE 062/081 063/082 062 07554
CMI EE 059/081 061/082 061 07554
MTO EE 062/082 063/082 062 07454
LWV BE 064/083 065/083 063 07344

.ILX...NONE.

KH

ILZ027>031-036>038-040>057-061>063-066>068-071>073-271730-

HAZARDOUS WEATHER OUTLOOK FOR CENTRAL ILLINOIS
NATIONAL WEATHER SERVICE LINCOLN IL
1122 AM CDT MON MAY 27 2002

THUNDERSTORMS OVER WEST CENTRAL ILLINOIS WILL CONTINUE TO
MOVE INTO THE REMAINDER OF THE AREA THIS AFTERNOON. SOME OF
THE STRONGER STORMS COULD PRODUCE SMALL HAIL AND GUSTY WINDS...ALONG
WITH BRIEF HEAVY RAINFALL AS THEY TRACK ACROSS CENTRAL ILLINOIS THIS
AFTERNOON AND INTO THIS EVENING.

AUTEN