518 WHUS53 KLOT 180204 SMWLOT LMZ741>745-779-180400- /O.NEW.KLOT.MA.W.0028.260418T0204Z-260418T0400Z/ BULLETIN - IMMEDIATE BROADCAST REQUESTED Special Marine Warning National Weather Service Chicago/Romeoville 904 PM CDT Fri Apr 17 2026 The National Weather Service in Chicago has issued a * Special Marine Warning for... Nearshore Waters from Wilmette Harbor to Calumet Harbor... Nearshore Waters from Calumet Harbor to Michigan City... Open Waters from Wilmette Harbor to Michigan City out to Mid Lake... * Until 1100 PM CDT. * At 904 PM CDT, severe thunderstorms capable of producing waterspouts were located along a line extending from 13 nm west of Elgin to 9 nm southwest of Aurora to 29 nm southwest of Joliet, moving east at 40 knots. HAZARD...Waterspouts and wind gusts in excess of 65 knots. SOURCE...Radar. IMPACT...Waterspouts can easily overturn boats and create locally hazardous seas. Boats could suffer significant structural damage in high winds. Small craft could capsize in suddenly higher waves. * Locations impacted include... Calumet Harbor, Indiana Harbor, 31st Street Harbor, Monroe Harbor, Burns Harbor, Marina Shores at Dune Harbor, Burnham Harbor, 59th Street Marina, Hammond Marina, Jackson Park Harbor, and DuSable Harbor. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Tornado Watch remains in effect until 1100 PM CDT for northeastern Illinois...northwestern Indiana...and the adjacent waters of Lake Michigan. Move to safe harbor immediately as gusty winds and high waves are expected. Thunderstorms can produce sudden waterspouts. Waterspouts can easily overturn boats and create locally hazardous seas. Seek safe harbor immediately. && LAT...LON 4162 8733 4164 8743 4168 8743 4167 8744 4169 8750 4175 8753 4179 8758 4178 8758 4188 8762 4211 8696 4179 8697 4179 8696 4172 8691 4166 8709 4165 8714 4163 8716 4162 8732 4161 8732 TIME...MOT...LOC 0204Z 257DEG 42KT 4198 8858 4167 8844 4122 8862 WATERSPOUT...POSSIBLE HAIL...0.00IN WIND...65KTS $$ Yack  505 WHUS53 KMKX 180234 SMWMKX LMZ646-671-673-675-180315- /O.NEW.KMKX.MA.W.0019.260418T0234Z-260418T0315Z/ BULLETIN - IMMEDIATE BROADCAST REQUESTED Special Marine Warning National Weather Service Milwaukee/Sullivan WI 934 PM CDT Fri Apr 17 2026 The National Weather Service in Milwaukee/Sullivan has issued a * Special Marine Warning for... Nearshore waters from Wind Point WI TO Winthrop Harbor IL... Lake Michigan from Port Washington WI to Winthrop Harbor IL... * Until 1015 PM CDT. * At 934 PM CDT, severe thunderstorms capable of producing waterspouts were located along a line extending from 35 nm west of Grand Haven Light to 25 nm east of Wind Pt. to 13 nm east of Winthrop Harbor, moving east at 35 knots. HAZARD...Waterspouts and wind gusts 34 knots or greater. SOURCE...Radar. IMPACT...Waterspouts can easily overturn boats and create locally hazardous seas. Small craft could be damaged in briefly higher winds and suddenly higher waves. * Severe thunderstorms will remain over mainly open waters. PRECAUTIONARY/PREPAREDNESS ACTIONS... Move to safe harbor until hazardous weather passes. && LAT...LON 4249 8780 4261 8782 4267 8781 4267 8779 4270 8777 4277 8776 4279 8766 4306 8737 4307 8710 4246 8702 TIME...MOT...LOC 0234Z 251DEG 35KT 4290 8703 4265 8721 4244 8750 WATERSPOUT...POSSIBLE HAIL...0.00IN WIND...>34KTS $$ WAGNER  847 WHUS53 KIWX 180259 SMWIWX LMZ043-046-080-180500- /O.NEW.KIWX.MA.W.0012.260418T0259Z-260418T0500Z/ BULLETIN - IMMEDIATE BROADCAST REQUESTED Special Marine Warning National Weather Service Northern Indiana 1059 PM EDT Fri Apr 17 2026 The National Weather Service in Northern Indiana has issued a * Special Marine Warning for... Lake Michigan Michigan City IN to St. Joseph MI 5 NM offshore to mid-line of lake.... Michigan City IN to New Buffalo MI... New Buffalo MI to St Joseph MI... * Until 100 AM EDT. * At 1059 PM EDT, strong thunderstorms were located along a line extending from 33 nm east of Winthrop Harbor to 6 nm northeast of Joliet, moving east at 40 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... New Buffalo and Michigan City. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Tornado Watch remains in effect until 300 AM EDT for northwestern Indiana...southwestern Michigan...and the adjacent waters of Lake Michigan. Move to safe harbor until hazardous weather passes. && LAT...LON 4179 8696 4179 8697 4212 8696 4213 8657 4211 8649 4194 8658 4189 8662 4180 8675 4179 8676 4172 8691 TIME...MOT...LOC 0259Z 264DEG 41KT 4252 8704 4162 8805 HAIL...0.00IN WIND...49KTS $$ MCS  787 WHUS53 KLOT 180259 SMWLOT LMZ740-741-745-777-779-180430- /O.NEW.KLOT.MA.W.0029.260418T0259Z-260418T0430Z/ BULLETIN - IMMEDIATE BROADCAST REQUESTED Special Marine Warning National Weather Service Chicago/Romeoville 959 PM CDT Fri Apr 17 2026 The National Weather Service in Chicago has issued a * Special Marine Warning for... Nearshore Waters from Winthrop Harbor to Northerly Island... Nearshore Waters from Burns Harbor to Michigan City... Open Waters from Winthrop Harbor to Michigan City out to Mid Lake... * Until 1130 PM CDT. * At 959 PM CDT, strong thunderstorms were located along a line extending from Waukegan Harbor to near Wilmette Harbor to near Montrose Harbor to 16 nm south of Joliet, moving northeast at 45 knots. HAZARD...Wind gusts to nearly 50 knots. SOURCE...Radar. IMPACT...Small craft could be damaged in briefly higher winds and suddenly higher waves. * Locations impacted include... Harrison-Dever Crib, Wilmette Harbor, Winthrop Harbor, Montrose Harbor, Monroe Harbor, Waukegan Harbor, Burns Harbor, Belmont Harbor, Diversy Harbor, and DuSable Harbor. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Tornado Watch remains in effect until 1100 PM CDT for northeastern Illinois...and the adjacent waters of Lake Michigan. Move to safe harbor until hazardous weather passes. && LAT...LON 4172 8691 4165 8715 4178 8721 4198 8726 4187 8762 4189 8762 4189 8760 4190 8762 4206 8767 4214 8775 4227 8783 4248 8780 4246 8702 4213 8696 4179 8697 4179 8696 TIME...MOT...LOC 0259Z 239DEG 44KT 4236 8782 4214 8773 4197 8772 4127 8798 HAIL...0.00IN WIND...49KTS $$ Izzi