854
FLUS43 KLOT 230909
HWOLOT
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
409 AM CDT WED JUL 23 2025
ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-240915-
WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DUPAGE-
LA SALLE-KENDALL-GRUNDY-KANKAKEE-LIVINGSTON-IROQUOIS-FORD-
NORTHERN COOK-CENTRAL COOK-SOUTHERN COOK-NORTHERN WILL-
SOUTHERN WILL-EASTERN WILL-LAKE IN-PORTER-NEWTON-JASPER-BENTON-
409 AM CDT WED JUL 23 2025 /509 AM EDT WED JUL 23 2025/
THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
ILLINOIS...NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
DAY ONE
TODAY AND TONIGHT.
WEATHER HAZARDS EXPECTED...
SIGNIFICANT EXCESSIVE HEAT RISK.
LIMITED THUNDERSTORM RISK.
DISCUSSION...
THERE IS A 20 PERCENT CHANCE OF ISOLATED THUNDERSTORMS EARLY THIS
MORNING OVER NORTHWEST ILLINOIS. A FEW ADDITIONAL ISOLATED
THUNDERSTORMS MAY DEVELOP ACROSS PARTS OF NORTHERN ILLINOIS THIS
AFTERNOON.
DANGEROUS HEAT AND HUMIDITY WITH PEAK AFTERNOON HEAT INDEX VALUES
OF 100 TO 110 DEGREES ARE EXPECTED THIS AFTERNOON.
DAYS TWO THROUGH SEVEN
THURSDAY THROUGH TUESDAY.
THURSDAY...
SIGNIFICANT EXCESSIVE HEAT RISK.
ELEVATED THUNDERSTORM RISK...WITH AN ASSOCIATED:
LEVEL 1 OF 5 SEVERE THUNDERSTORM RISK.
ELEVATED FLOODING RISK.
FRIDAY...
ELEVATED THUNDERSTORM RISK.
ELEVATED FLOODING RISK.
SATURDAY...
ELEVATED THUNDERSTORM RISK.
LIMITED FLOODING RISK.
SUNDAY THROUGH MONDAY...
LIMITED EXCESSIVE HEAT RISK.
DISCUSSION...
DANGEROUS HEAT AND HUMIDITY WITH PEAK AFTERNOON HEAT INDEX VALUES
OF 100 TO 110 DEGREES ARE EXPECTED AGAIN THURSDAY.
THE CHANCE OF THUNDERSTORMS WILL INCREASE LATE THURSDAY AFTERNOON
NEAR THE WISCONSIN BORDER, WITH THUNDERSTORM CHANCES GRADUALLY
SPREADING SOUTH ACROSS THE REMAINDER OF NORTHERN ILLINOIS
THURSDAY EVENING. ANY THUNDERSTORMS THAT DO OCCUR WILL BE CAPABLE
OF PRODUCING TORRENTIAL RAINFALL AND LOCALIZED FLASH FLOODING
WITH A SLIGHT CHANCE OF LOCALLY DAMAGING WINDS.
PERIODIC THUNDERSTORMS FRIDAY THROUGH SATURDAY WILL BRING THE
CHANCE FOR TORRENTIAL RAINFALL AND LOCALIZED FLOODING.
SPOTTER INFORMATION STATEMENT
SPOTTER ACTIVATION WILL NOT BE NECESSARY THROUGH TONIGHT.
GENERAL STORM MOTION OF THE DAY:
MOVING TOWARD THE EAST-NORTHEAST AT 15 TO 20 MPH.
LMZ740>745-240915-
WINTHROP HARBOR TO WILMETTE HARBOR IL-
WILMETTE HARBOR TO NORTHERLY ISLAND IL-
NORTHERLY ISLAND TO CALUMET HARBOR IL-
CALUMET HARBOR IL TO GARY IN-GARY TO BURNS HARBOR IN-
BURNS HARBOR TO MICHIGAN CITY IN-
409 AM CDT WED JUL 23 2025
THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF THE ILLINOIS
NEARSHORE WATERS OF LAKE MICHIGAN AND THE INDIANA NEARSHORE
WATERS OF LAKE MICHIGAN.
DAY ONE
TODAY AND TONIGHT.
WEATHER HAZARDS EXPECTED...
LIMITED THUNDERSTORM RISK.
DAYS TWO THROUGH SEVEN
THURSDAY THROUGH TUESDAY.
THURSDAY...
ELEVATED THUNDERSTORM RISK...WITH AN ASSOCIATED:
LEVEL 1 OF 5 SEVERE THUNDERSTORM RISK.
FRIDAY...
LIMITED THUNDERSTORM RISK.
SATURDAY...
ELEVATED THUNDERSTORM RISK.
KJB
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