Marine Thunderstorm Winds in Lake Michigan, August 9, 2004

Name: Marine Thunderstorm Winds in Lake Michigan, August 9, 2004
Start: 2004-08-09T15:55
End: 2004-08-09T15:55
Location: Lake Michigan

August 9, 2004 · NWS GRB · 2 events in 2 counties and zones

A line of thunderstorms ahead of an approaching cold front produced wind gusts to 44 knots at Kap's Marina on Washington Island.

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS GRB wrote it up.

A line of thunderstorms ahead of an approaching cold front produced wind gusts to 44 knots at Kap's Marina on Washington Island.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Green Bay, WI wrote its last area forecast discussion before the first event at Aug 9, 3:00 PM CST, 55 minutes earlier.

Area forecast discussion, Aug 9, 3:00 PM CST, 55 minutes before

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Hazardous weather outlook, Aug 9, 10:45 AM CST, 5 hours 10 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREEN BAY WI
1145 AM CDT MON AUG 9 2004

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-101100-
VILAS-ONEIDA-FOREST-FLORENCE-NORTHERN MARINETTE-SOUTHERN MARINETTE-
LINCOLN-LANGLADE-MENOMINEE-NORTHERN OCONTO-SOUTHERN OCONTO-DOOR-
MARATHON-SHAWANO-WOOD-PORTAGE-WAUPACA-OUTAGAMIE-BROWN-KEWAUNEE-WAUSHARA-
WINNEBAGO-CALUMET-MANITOWOC-
1145 AM CDT MON AUG 9 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH-CENTRAL AND NORTHEAST
WISCONSIN.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A LOW PRESSURE SYSTEM MOVING OVER LAKE SUPERIOR TODAY WILL DRAG A
COLD FRONT THROUGH WISCONSIN BY EVENING. SHOWERS AND ISOLATED
THUNDERSTORMS DEVELOPED BEHIND THE FRONT IN ASSOCIATION WITH A MID LEVEL
LOW. THUNDERSTORMS WILL DEVELOP AHEAD OF THE FRONT AS IT MOVES EAST
ACROSS THE STATE INTO A MOIST AND UNSTABLE AIRMASS. SOME OF THESE STORMS
MAY BE SEVERE...PRODUCING DAMAGING WINDS AND LARGE HAIL THIS AFTERNOON.
ISOLATED TORNADOES ARE ALSO POSSIBLE.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

UNSEASONABLY COOL AIR ALOFT WILL SETTLE OVER NORTHERN WISCONSIN ON
TUESDAY.  CLOUDS AND SCATTERED SHOWERS CAN BE EXPECTED.  ANY BREAKS IN
THE CLOUD COVER MAY RESULT IN ENOUGH INSTABILITY TO PRODUCE ISOLATED NON
SEVERE THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON.

MG
WWW.CRH.NOAA.GOV/GRB

In the hours before

Local storm report, Aug 9, 2:31 PM CST, 1 hour 24 minutes before

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Special weather statement, Aug 9, 3:40 PM CST, 15 minutes before

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Event by event

2 marine thunderstorm wind. Local standard time, as filed.

Marine Thunderstorm Wind, Rock Is Psg to Sturgeon Bay Wi

When: August 9, 3:55 PM CST
Where: Rock Is Psg to Sturgeon Bay Wi marine zone, Washington Island
Measured: 44 kt (51 mph) measured gust
Reported by: MARINER

Marine Thunderstorm Wind, Lm Rock Is Psg to Sheboygan Wi Ewd Byd 5nm to Mid Line of Lake

When: August 9, 3:55 PM CST
Where: Lm Rock Is Psg to Sheboygan Wi Ewd Byd 5nm to Mid Line of Lake marine zone, Washington Island
Measured: 44 kt (51 mph) measured gust
Reported by: MARINER

What these are

Marine Thunderstorm Wind: Thunderstorm winds of 34 knots or more over coastal or lake waters.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Lake Michigan in 2004 Every state in 2004 This day in weather history

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 5419358, 5419359.