NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
.DAY ONE...TODAY AND TONIGHT.
WEATHER HAZARDS EXPECTED:
THUNDERSTORMS...SOME MAY PRODUCE:
HEAVY RAINFALL WITH FLASH FLOODING.
FREQUENT LIGHTNING.
OPPRESSIVE HEAT AND HUMIDITY.
AREAS AFFECTED AND TIMING:
THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP OVER NORTHERN
ILLINOIS AND NORTHWEST INDIANA. THE HEAVIEST STORMS...PRODUCING
VERY HEAVY RAINFALL ARE EXPECTED GENERALLY NORTH OF THE
INTERSTATE 80 CORRIDOR.
THE DANGEROUS HEAT AND HUMIDITY WILL CONTINUE...ESPECIALLY
SOUTH OF INTERSTATE 80.
DISCUSSION:
STRONG THUNDERSTORMS PRODUCED VERY HEAVY RAINFALL OVERNIGHT
WITH AMOUNTS UP TO 7 INCHES ALREADY OBSERVED AT SOME LOCATIONS
OVER THE DES PLAINES RIVER BASIN. LOCATIONS ON THE DES PLAINES
RIVER HAVE RAPIDLY REACHED FLOOD STAGE AND WILL CONTINUE TO
RISE THIS MORNING.
WITH ADDITIONAL HEAVY RAINFALL CONTINUING THROUGH THE MORNING
HOURS...ADDITIONAL FLASH FLOODING IS LIKELY. THE MOST LIKELY
LOCATION FOR FLASH FLOODING WILL BE ALONG AND NORTH OF
INTERSTATE 88.
MORE THUNDERSTORMS ARE TONIGHT. HEAVY RAIN ASSOCIATED WITH
THESE STORMS WILL FALL OVER THE SAME AREAS THAT EXPERIENCED
HEAVY RAIN THIS MORNING. THIS MAY CAUSE ADDITIONAL FLASH
FLOODING TONIGHT.
WITH INCREASING SUNSHINE LATER TODAY...LOCATIONS SOUTH OF
INTERSTATE 80 SHOULD SEE TEMPERATURES RISE INTO THE MIDDLE 90S.
WITH HIGH HUMIDITY ALREADY IN PLACE...HEAT INDEX VALUES SHOULD
REACH 110 TO 115 DEGREES.
LOCATIONS ALONG THE INTERSTATE 39 CORRIDOR AND JUST NORTH OF
THE INTERSTATE 80 CORRIDOR...AWAY FROM THE CHICAGO METRO
AREA...SHOULD SEE TEMPERATURES REACH INTO THE LOW 90S. HEAT
INDEX VALUES SHOULD REACH AROUND 105 DEGREES THERE. THE HEAT
INDEX OVER THE CHICAGO METRO AREA SHOULD BE BETWEEN 95 AND 100
DEGREES.
.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.
LOCATIONS SOUTH OF INTERSTATE 80 WILL SEE HEAT INDEX VALUES OF 110
TO 115 DEGREES ON SUNDAY.
LOCATIONS ALONG THE INTERSTATE 80 CORRIDOR WILL SEE HEAT INDEX
VALUES OF AROUND 105 TO 110 DEGREES ON SUNDAY.
THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS SUNDAY AND AGAIN
WEDNESDAY THROUGH FRIDAY.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NECESSARY THROUGH TONIGHT...ESPECIALLY
FOR FLASH FLOODING.
&&
COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO
