Active Weather Alerts
Flood Watch
Issued: 7:21 PM Aug. 18, 2025 – National Weather Service
...FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT... * WHAT...Flash flooding caused by excessive rainfall is possible. * WHERE...For the following counties, in Illinois, Boone, Cook, De Kalb, DuPage, Grundy, Kane, Kankakee, Kendall, La Salle, Lake, Lee, McHenry, Ogle, Will, and Winnebago, and for Lake and Porter counties in Indiana. * WHEN...Through late tonight. * IMPACTS...Creeks and streams may rise out of their banks. Flooding may occur in poor drainage and urban areas. Roads and streets may be flooded. Widespread, significant street flooding possible. Area creeks and streams are already elevated, reducing how much rainfall is needed for flooding to occur. * ADDITIONAL DETAILS... - Soil moisture in many areas is above average to much above average due to recent heavy rainfall. Rivers and streams across northern Illinois are above average to much above average for this time of year. Heavy thunderstorms with rainfall rates of 2 to 4 per hour are possible through tonight, due to atmospheric moisture content much above average for this time of year. If repeated rounds of thunderstorms were to affect the same location, then isolated rainfall totals in excess of 5 inches would be possible. Heavy rainfall is likely to cause flash flooding shortly after onset, especially in urbanized areas and areas that received heavy rainfall over the weekend. - http://www.weather.gov/safety/flood PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flood Watch for flash flooding means rapid-onset flooding is possible, but not yet certain, based upon the latest forecasts. Flash flooding is a dangerous situation. Persons with interests along area rivers, creeks, and other waterways should monitor the latest forecasts and be prepared to take action should flooding develop. &&
Marine Weather Statement
Issued: 7:02 PM Aug. 18, 2025 – National Weather Service
...A STRONG THUNDERSTORM APPROACHING THE WATERS... The areas affected include... Nearshore Waters from Winthrop Harbor to Wilmette Harbor... Open Waters from Winthrop Harbor to Wilmette Harbor out to Mid Lake... At 200 PM CDT, Doppler radar indicated a strong thunderstorm, capable of producing winds to around 30 knots and small hail. This thunderstorm was located 14 nm west of McHenry, or 34 nm west of Winthrop Harbor, moving east at 25 knots. Locations impacted include... Winthrop Harbor and Waukegan Harbor. PRECAUTIONARY/PREPAREDNESS ACTIONS... Mariners can expect gusty winds to around 30 knots, locally higher waves, lightning strikes, and heavy downpours. Boaters should seek safe harbor immediately until this storm passes. This strong thunderstorm will likely produce winds to around 30 knots, and could pose a serious hazard for boaters. A special marine warning may eventually be required when this strong thunderstorm reaches the nearshore waters. Boaters should consider heading for shore before this strong thunderstorm arrives. &&
Severe Thunderstorm Watch
Issued: 5:23 PM Aug. 18, 2025 – National Weather Service
THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH 599 IN EFFECT UNTIL 6 PM CDT THIS EVENING FOR THE FOLLOWING AREAS IN ILLINOIS THIS WATCH INCLUDES 14 COUNTIES IN NORTH CENTRAL ILLINOIS BOONE DE KALB LA SALLE LEE OGLE WINNEBAGO IN NORTHEAST ILLINOIS COOK DUPAGE GRUNDY KANE KENDALL LAKE IL MCHENRY WILL THIS INCLUDES THE CITIES OF ALGONQUIN, AURORA, BELVIDERE, BOLINGBROOK, BUFFALO GROVE, BYRON, CAROL STREAM, CHICAGO, COAL CITY, CRYSTAL LAKE, DEKALB, DIXON, DOWNERS GROVE, ELGIN, EVANSTON, GURNEE, JOLIET, LA SALLE, LEMONT, LOMBARD, MARSEILLES, MCHENRY, MENDOTA, MINOOKA, MORRIS, MUNDELEIN, NAPERVILLE, OAK LAWN, OREGON, ORLAND PARK, OSWEGO, OTTAWA, PARK FOREST, PLANO, ROCHELLE, ROCKFORD, SCHAUMBURG, STREATOR, SYCAMORE, WAUKEGAN, WHEATON, WILMINGTON, WOODSTOCK, AND YORKVILLE.
Severe Thunderstorm Watch
Issued: 5:23 PM Aug. 18, 2025 – National Weather Service
THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH 599 IN EFFECT UNTIL 6 PM CDT THIS EVENING FOR THE FOLLOWING AREAS THIS WATCH INCLUDES THE FOLLOWING ADJACENT COASTAL WATERS WINTHROP HARBOR TO WILMETTE HARBOR IL WILMETTE HARBOR TO NORTHERLY ISLAND IL NORTHERLY ISLAND TO CALUMET HARBOR IL LAKE MICHIGAN FROM WINTHROP HARBOR TO WILMETTE HARBOR IL 5NM OFFSHORE TO MID LAKE LAKE MICHIGAN FROM WILMETTE HARBOR IL TO MICHIGAN CITY IN 5NM OFFSHORE TO MID LAKE
Beach Hazard Statement
Issued: 4:02 PM Aug. 18, 2025 – National Weather Service
...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 3 PM CDT THIS AFTERNOON... * WHAT...High wave action and dangerous currents expected at Lake Michigan beaches. Waves 3 to 5 ft are occurring. * WHERE...Lake IL, Northern Cook and Central Cook Counties. * WHEN...Until 3 PM CDT this afternoon. * IMPACTS...Swimming conditions will be life threatening, especially for inexperienced swimmers. For information on swim advisories or bans at Chicago beaches: www. cpdbeaches. com. PRECAUTIONARY/PREPAREDNESS ACTIONS... Remain out of the water to avoid dangerous swimming conditions and do not venture out onto piers, jetties, breakwalls, or other shoreline structures. &&
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