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United States Warnings, Watches, And Advisories Special Marine Warning
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Special Marine Warning
In effect:
Friday, Apr 17 2026 9:59 PM CDT – Friday, Apr 17 2026 11:30 PM CDT
Issued by NWS Chicago IL
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.
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.
Harrison-Dever Crib, Wilmette Harbor, Winthrop Harbor, Montrose
Harbor, Monroe Harbor, Waukegan Harbor, Burns Harbor, Belmont
Harbor, Diversy Harbor, and DuSable Harbor.
Instructions:
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.
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.
Areas Impacted:
Winthrop Harbor to Wilmette Harbor IL
Wilmette Harbor to Northerly Island IL
Burns Harbor to Michigan City IN
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM offshore to Mid Lake
Lake Michigan from Wilmette Harbor to Michigan City in 5NM offshore to Mid Lake
Special Marine Warning
In effect:
Friday, Apr 17 2026 10:59 PM EDT – Saturday, Apr 18 2026 1:00 AM EDT
Issued by NWS Northern Indiana
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.
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.
New Buffalo and Michigan City.
Instructions:
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.
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.
Areas Impacted:
New Buffalo MI to St Joseph MI
Michigan City IN to New Buffalo MI
Lake Michigan Michigan City IN to St. Joseph MI 5 NM offshore to mid-line of lake.
Special Marine Warning
In effect:
Friday, Apr 17 2026 10:48 PM EDT – Saturday, Apr 18 2026 12:45 AM EDT
Issued by NWS Grand Rapids MI
A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 1245 AM EDT
Hazard:
Wind gusts to 40 knots and small hail.
Wind gusts to 40 knots and small hail.
Source:
Radar indicated.
Radar indicated.
Impact:
Small craft could be damaged in briefly higher winds and
suddenly higher waves.
Locations impacted include...
South Haven Light, St. Joseph Light, White Lake Pier Heads, Mona Lake
Channel, Holland Light, The White Lake Pierheads, Muskegon Light, and
St. Joseph.
Small craft could be damaged in briefly higher winds and
suddenly higher waves.
Locations impacted include...
South Haven Light, St. Joseph Light, White Lake Pier Heads, Mona Lake
Channel, Holland Light, The White Lake Pierheads, Muskegon Light, and
St. Joseph.
Instructions:
Move to safe harbor until hazardous weather passes.
Move to safe harbor until hazardous weather passes.
Areas Impacted:
St Joseph to South Haven MI
South Haven to Holland MI
Holland to Grand Haven MI
Grand Haven to Whitehall MI
Lake Michigan from Grand Haven to Whitehall MI 5NM offshore to Mid Lake
Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid Lake
Lake Michigan from South Haven to Holland MI 5NM offshore to Mid lake
Lake Michigan from St Joseph to South Haven MI 5NM offshore to Mid Lake
Special Marine Warning
In effect:
Friday, Apr 17 2026 9:46 PM CDT – Friday, Apr 17 2026 11:00 PM CDT
Issued by NWS Chicago IL
A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 1100 PM CDT
Hazard:
Waterspouts and wind gusts to nearly 50 knots.
Waterspouts and wind gusts to nearly 50 knots.
Source:
Radar indicated.
Radar indicated.
Impact:
Waterspouts can easily overturn boats and create locally
hazardous seas. Small craft could be damaged in briefly
higher winds and 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.
Waterspouts can easily overturn boats and create locally
hazardous seas. Small craft could be damaged in briefly
higher winds and 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.
Instructions:
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.
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.
Areas Impacted:
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
Lake Michigan from Wilmette Harbor to Michigan City in 5NM offshore to Mid Lake
Special Marine Warning
In effect:
Friday, Apr 17 2026 9:34 PM CDT – Friday, Apr 17 2026 10:15 PM CDT
Issued by NWS Milwaukee/Sullivan WI
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.
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.
Instructions:
Move to safe harbor until hazardous weather passes.
Move to safe harbor until hazardous weather passes.
Areas Impacted:
Wind Point WI to Winthrop Harbor IL
Lake Michigan from Port Washington to North Point Light WI 5NM offshore to Mid Lake
Lake Michigan from North Point Light to Wind Point WI 5NM offshore to Mid Lake
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5NM offshore to Mid Lake