NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
.DAY ONE...TONIGHT.
WEATHER HAZARDS EXPECTED:
THUNDERSTORMS...SOME MAY PRODUCE:
HEAVY RAINFALL WITH FLASH FLOODING.
FREQUENT LIGHTNING.
DAMAGING WINDS IN EXCESS OF 60 MPH.
OPPRESSIVE HEAT AND HUMIDITY.
AREAS AFFECTED AND TIMING:
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS EVENING
ACROSS PORTIONS OF NORTHWESTERN INDIANA. ADDITIONAL SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS PORTIONS
OF NORTHERN ILLINOIS FROM EASTERN IOWA THIS EVENING.
A SECOND AREA OF THUNDERSTORMS MAY DEVELOP LATER THIS EVENING
ACROSS NORTHERN IOWA. SHOULD THESE THUNDERSTORMS DEVELOP...THE
COMPLEX OF THUNDERSTORMS COULD TRACK ACROSS NORTHERN ILLINOIS
AND NORTHWESTERN INDIANA LATER TONIGHT. IT APPEARS THAT THE
BEST AREAS THAT MAY BE IMPACTED BY THESE THUNDERSTORMS WILL BE
SOME OF THE SAME AREAS ALREADY HIT BY HEAVY RAINFALL OVER THE
PAST FEW DAYS.
THE DANGEROUS HEAT AND HUMIDITY WILL CONTINUE...ESPECIALLY
SOUTH OF INTERSTATE 80.
DISCUSSION:
DUE TO THE HEAVY RAINFALL PRODUCED THIS MORNING ACROSS NORTHERN
ILLINOIS AND THE FACT THAT ADDITIONAL HEAVY RAINFALL IS
POSSIBLE LATER TONIGHT INTO SUNDAY ACROSS THE SAME
AREAS...THERE IS A HIGH THREAT FOR ADDITIONAL FLASH FLOODING.
MUCH IF NOT ALL OF ANY RAINFALL THAT FALLS ACROSS NORTHERN
ILLINOIS WILL BE CONVERTED TO RUNOFF DUE TO THE SATURATED
GROUND. THIS RUNOFF COULD EASILY OVERWHELM SMALL STREAMS AND
DRAINAGE BASINS.
ALSO DUE TO THE HEAVY RAINFALL OVER THE PAST 48 HOURS LOCATIONS
ON THE DES PLAINES RIVER HAVE RAPIDLY REACHED FLOOD STAGE AND
WILL CONTINUE TO RISE THROUGH THIS EVENING.
LOCATIONS ALONG AND SOUTH OF INTERSTATE 80 SHOULD SEE VERY WARM
TEMPERATURES TONIGHT...WITH LOWS ONLY DROPPING INTO THE MID TO
UPPER 70S.
.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
