Active Weather Alerts
Special Marine Warning
Issued: 9:29 PM Aug. 18, 2025 – National Weather Service
The National Weather Service in Chicago has issued a * Special Marine Warning for... Nearshore Waters from Winthrop Harbor to Calumet Harbor... Open Waters from Winthrop Harbor to Michigan City out to Mid Lake... * Until 630 PM CDT. * At 429 PM CDT, strong thunderstorms were located along a line extending from 6 nm southwest of McHenry to Elgin to 9 nm northwest of Aurora, moving east at 30 knots. HAZARD...Wind gusts to nearly 50 knots. SOURCE...Radar. IMPACT...Small craft could be damaged in briefly higher winds and suddenly higher waves. * Locations impacted include... Harrison-Dever Crib, Belmont Harbor, Calumet Harbor, Burnham Harbor, 59th Street Marina, Wilmette Harbor, Jackson Park Harbor, 31st Street Harbor, Montrose Harbor, Monroe Harbor, Diversy Harbor, and DuSable Harbor. PRECAUTIONARY/PREPAREDNESS ACTIONS... Move to safe harbor until hazardous weather passes. && HAIL...0.00IN; WIND...49KTS
Severe Thunderstorm Warning
Issued: 9:25 PM Aug. 18, 2025 – National Weather Service
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM CDT FOR EAST CENTRAL DE KALB...KANE...NORTHERN DUPAGE AND NORTHWESTERN COOK COUNTIES... At 424 PM CDT, severe thunderstorms were located along a line extending from near Gilberts to near Sleepy Hollow to Campton Hills to Elburn, moving east at 30 mph. HAZARD...70 mph wind gusts. SOURCE...Radar indicated. IMPACT...Expect considerable tree damage. Damage is likely to mobile homes, roofs, and outbuildings. These severe storms will be near... Barrington Hills, Carpentersville, Algonquin, Geneva, Sleepy Hollow, Elburn, St. Charles, Valley View, Elgin, and Wayne around 430 PM CDT. Barrington, Inverness, Carol Stream, and Roselle around 440 PM CDT. Itasca, Arlington Heights, and Addison around 450 PM CDT. Wheeling, Rosemont, Chicago, Villa Park, and Elmhurst around 500 PM CDT. Northbrook, Glenview, Northlake, Franklin Park, Ohare Airport, Schiller Park, Park Ridge, and Niles around 505 PM CDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... Remain alert for a possible tornado! Tornadoes can develop quickly from severe thunderstorms. If you spot a tornado go at once into the basement or small central room in a sturdy structure. For your protection move to an interior room on the lowest floor of a building. && TORNADO...POSSIBLE; THUNDERSTORM DAMAGE THREAT...CONSIDERABLE; HAIL THREAT...RADAR INDICATED; MAX HAIL SIZE...<.75 IN; WIND THREAT...RADAR INDICATED; MAX WIND GUST...70 MPH
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. &&
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
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