NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
.DAY ONE...TONIGHT.
WEATHER HAZARDS EXPECTED:
THUNDERSTORMS...THE STRONGEST STORMS MAY PRODUCE:
HEAVY DOWNPOURS.
FREQUENT LIGHTNING.
SMALL HAIL.
AREAS AFFECTED AND TIMING:
THERE IS A CHANCE OF THUNDERSTORMS...GENERALLY ACROSS NORTHERN
ILLINOIS LATE TONIGHT.
DISCUSSION:
AN INFLUX OF WARM HUMID AIR IS EXPECTED TO REACH NORTHERN
ILLINOIS AND NORTHWEST INDIANA OVERNIGHT. THIS MAY ALLOW MORE
WIDESPREAD THUNDERSTORM ACTIVITY OVER IOWA AND MISSOURI THIS
EVENING...TO DEVELOP EASTWARD INTO THE FORECAST AREA...ESPECIALLY
ACROSS WESTERN AND SOUTHERN PORTIONS OF THE OUTLOOK AREA. THESE
STORMS MAY REACH AREAS WEST OF INTERSTATE 39 ABOUT MIDNIGHT OR
SHORTLY THEREAFTER...THEN SPREAD EASTWARD DURING THE OVERNIGHT
HOURS.
PORTIONS OF THE UPPER ILLINOIS RIVER WILL REMAIN NEAR BANK FULL.
.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.
THUNDERSTORMS ARE LIKELY MONDAY AND MONDAY NIGHT AS A COLD FRONT
MOVES ACROSS THE FORECAST AREA. SOME STORMS MAY BECOME SEVERE
MONDAY AFTERNOON AND EVENING.
PORTIONS OF THE UPPER ILLINOIS RIVER WILL REMAIN NEAR BANK-FULL
THROUGH SUNDAY EVENING. PERIODS OF HEAVY RAINFALL MONDAY AND
MONDAY EVENING MAY CAUSE ADDITIONAL RISES ON AREA STREAMS AND
RIVERS.
HIGH TEMPERATURES ARE EXPECTED TO REACH WELL INTO THE 90S ON
FRIDAY...IN COMBINATION WITH DEW POINTS IN THE LOWER 70S. THIS
WILL PRODUCE HEAT INDEX VALUES BETWEEN 100 AND 105 FRIDAY
AFTERNOON.
THERE IS A CHANCE OF THUNDERSTORMS FRIDAY NIGHT AND SATURDAY.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NECESSARY THROUGH TONIGHT.
&&
COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO
