NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
.DAY ONE...TONIGHT.
WEATHER HAZARDS EXPECTED:
HEAT INDEX VALUES FROM 100 TO 109
THUNDERSTORMS...A FEW MAY PRODUCE
DAMAGING WIND GUSTS IN EXCESS OF 60 MPH.
LARGE HAIL.
AND HEAVY RAINFALL.
AREAS AFFECTED AND TIMING:
HEAT INDEX VALUES ARE IN THE 100 TO 109 RANGE THIS AFTERNOON AND
WILL CONTINUE THROUGH THE MID EVENING BEFORE WE BEGIN TO SEE
VALUES DECREASE AS WE LOSE SUNLIGHT.
THUNDERSTORM CHANCES WILL INCREASE FROM NORTH TO SOUTH ACROSS THE
ENTIRE OUTLOOK AREA EARLY THIS EVENING.
DISCUSSION:
A COLD FRONT SPANNING EAST CENTRAL WISCONSIN SOUTHWEST INTO IOWA
WILL CONTINUE TO PUSH SOUTHEAST THROUGH THE EVENING WITH
THUNDERSTORMS DEVELOPING ALONG AND JUST AHEAD OF THE FRONT. THE
PRIMARY THREAT THIS EVENING WILL BE DAMAGING STRAIGHT LINE WINDS.
THUNDERSTORMS ARE EXPECTED TO DEVELOP INTO LINEAR SEGMENTS OR BOWS
THIS EVENING...HOWEVER ISOLATED SUPERCELLS EARLY IN THE EVOLUTION
THIS EVENING MAY BRING A LARGE HAIL THREAT INITIALLY. ALSO
ISOLATED TORNADOES CANNOT BE RULED OUT WHERE BOWING SEGMENTS
INTERACT WITH REMNANT OUTFLOW BOUNDARIES ACROSS THE AREA. THE
STORMS WILL BE EFFICIENT RAINFALL PRODUCERS SO A QUICK INCH OR SO
OF RAIN WILL CERTAINLY BE POSSIBLE BUT STORMS ARE EXPECTED TO BE
MOVING ALONG QUICKLY. THIS WILL KEEP THE THREAT OF FLASH FLOODING
LOW.
.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.
THERE IS ANOTHER CHANCE OF THUNDERSTORMS THURSDAY NIGHT THROUGH
FRIDAY...THEN AGAIN SATURDAY NIGHT THROUGH MONDAY.
THERE IS AN INCREASED RISK OF RIP CURRENTS ALONG THE INDIANA AND
ILLINOIS SHORES OF LAKE MICHIGAN WEDNESDAY...AND ALONG THE INDIANA
SHORES WEDNESDAY EVENING.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS LIKELY TONIGHT.
&&
COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO
