NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
.DAY ONE...THIS AFTERNOON AND TONIGHT.
WEATHER HAZARDS EXPECTED:
OPPRESSIVE HEAT AND HUMIDITY.
THUNDERSTORMS...SOME MAY PRODUCE:
HEAVY RAINFALL WITH FLASH FLOODING.
WINDS OVER 60 MPH.
FREQUENT LIGHTNING.
AREAS AFFECTED AND TIMING:
THE DANGEROUS HEAT AND HUMIDITY WILL CONTINUE SOUTH OF
INTERSTATE 80.
SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS
NORTHWEST INDIANA INTO EARLY THIS AFTERNOON. PERIODS OF VERY
HEAVY RAINFALL AND WIND GUSTS TO 50 MPH WILL ACCOMPANY THESE
STORMS. RUNOFF FROM THIS RAINFALL MAY LEAD TO SOME LOCALIZED
FLASH FLOODING.
THESE THUNDERSTORMS SHOULD MOVE EAST OF THE AREA BY EARLY THIS
AFTERNOON. THERE IS A CHANCE THAT ADDITIONAL STORMS MAY DEVELOP
LATER THIS AFTERNOON. HOWEVER...IT APPEARS THE BEST POTENTIAL
FOR THESE STORMS WILL BE SOUTH OF THE KANKAKEE AND ILLINOIS
RIVERS. IF ADDITIONAL STORMS DEVELOP IN THIS REGION THEY MAY BE
SEVERE WITH STRONG DAMAGING WINDS.
DISCUSSION:
HEAT INDEX VALUES WILL ONCE AGAIN BE UP TO 110 DEGREES SOUTH OF
INTERSTATE 80.
THERE IS A CHANCE FOR ADDITIONAL THUNDERSTORMS DEVELOPMENT
SOUTH OF THE KANKAKEE AND ILLINOIS RIVERS THIS AFTERNOON. GIVEN
THE EXTREMELY UNSTABLE ATMOSPHERE... THERE IS THE POTENTIAL THAT
STORMS THAT DEVELOP MAY BECOME SEVERE PRODUCING
STRONG...DAMAGING WIND GUSTS.
.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.
HEAT INDEX VALUES OF 100 TO 105 DEGREES ACROSS MUCH OF NORTHERN
ILLINOIS AND NORTHWEST INDIANA ARE EXPECTED FOR THE WEEKEND. ONLY
FAR NORTHEASTERN ILLINOIS MAY ESCAPE THE OPPRESSIVE HEAT.
CONSIDERABLE UNCERTAINTY REMAINS AS TO THE NORTHWARD EXTENT OF THE
HEAT. ADDITIONAL THUNDERSTORMS ON SATURDAY MAY LIMIT THE NORTHWARD
PROGRESS OF THE WARM AIR MASS. THEREFORE IT IS POSSIBLE THAT THE
MOST EXTREME HEAT WILL REMAIN SOUTH OF INTERSTATE 80.
THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS THROUGH THE
WEEKEND AND AGAIN BY THE MIDDLE OF NEXT WEEK.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED THIS LATE THIS AFTERNOON.
&&
COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO
