NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
.DAY ONE...THIS AFTERNOON AND TONIGHT.
WEATHER HAZARDS EXPECTED:
SCATTERED THUNDERSTORMS...SOME A FEW OF THE STRONGER STORMS MAY
PRODUCE:
DAMAGING WINDS...LARGE HAIL...FREQUENT LIGHTNING...HEAVY
DOWNPOURS.
AREAS AFFECTED AND TIMING:
THUNDERSTORMS WILL CONTINUE TO DEVELOP IN NORTHWEST AND WEST
CENTRAL ILLINOIS DURING THE LATE MORNING AND BECOME MORE NUMEROUS
AS THEY SPREAD INTO NORTH CENTRAL AND NORTHEAST ILLINOIS EARLY TO
MID AFTERNOON...AND NORTHWEST INDIANA DURING MID TO LATE
AFTERNOON. THUNDERSTORMS ARE EXPECTED TO CONTINUE THROUGH TONIGHT
ACROSS THE AREA...MAINLY DURING THE EVENING HOURS.
DISCUSSION:
ISOLATED WERE THUNDERSTORMS DEVELOPING UPSTREAM OF THE LOCAL AREA
DURING THE LATE MORNING. THEY WILL CONTINUE TO INCREASE IN NUMBER
AND STRENGTH THIS AFTERNOON AS THEY MOVE INTO THE OUTLOOK AREA AS
DAY-TIME HEATING COMBINED WITH MID LEVEL COOLING ASSOCIATED WITH
AN APPROACHING SHORT WAVE TROUGH RESULT IN A CONTINUED
DESTABILIZATION OF THE ATMOSPHERE OVER THE AREA. THE DISTURBANCE
APPROACHING FROM MISSOURI WILL ALSO PROVIDE ORGANIZED LIFT ACROSS
THE AREA THIS AFTERNOON INTO THIS EVENING. MODELS SHOW THAT THE
THUNDERSTORMS WILL BE MOVING AT A RATHER QUICK SPEED SO WHILE
BRIEF HEAVY DOWNPOURS MAY OCCUR ONLY LOCALIZED FLOODING OF POOR
DRAINAGE AND LOW-LYING AREA CAN BE EXPECTED.
PORTIONS OF THE KANKAKEE AND ILLINOIS RIVERS WILL REMAIN IN
FLOOD.
.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.
THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS FOR THE ENTIRE
OUTLOOK AREA WEDNESDAY AND AGAIN LATE IN THE WEEKEND.
PORTIONS OF THE KANKAKEE AND ILLINOIS RIVERS WILL REMAIN IN
FLOOD.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NECESSARY THIS AFTERNOON AND EVENING.
&&
COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO
