Forecast and Warning Definitions

Storm Warning: Advancements in Marine Forecasting since the Edmund Fitzgerald

	Background Information:
		The Edmund Fitzgerald
		The Fall Storm Season
		Forecast and Warning Definitions
		Resources, Links and Credits
		Advances in:
		Scientific Understanding
		Numerical Weather Prediction
		Communications
		Radars and Satellites
		Observations and Forecasts
		Back to:
		Main Page
		NWS Marquette Home Page

Forecast and Warning Definitions

National Weather Service Marquette marine responsibility The National Weather Service issues forecasts and warnings for the U.S. open waters (waters beyond five nautical miles from shore) and for the nearshore waters (waters within five nautical miles from shore) of the Great Lakes - darker shaded areas in image to the left.

Lake Superior Forecasts for the open waters are issued four times daily throughout the year, at 4:00am, plus every six hours with intermediate updates as necessary. Nearshore Marine Forecasts are issued four times daily, at 5:00am plus every six hours with intermediate updates as necessary.

Forecast wave heights are for the average of the highest third of the waves at the end of the fetch in the forecast area. Wind directions and speeds are forecast for roughly 33 feet above the lake surface.

Marine warnings and advisories are headlined within marine forecasts:

Small Craft Advisories for winds 22 to 33 knots inclusive and/or average waves greater than four feet for nearshore waters
Gale Warnings for winds 34 to 47 knots inclusive
Storm Warnings for winds 48 to 63 knots inclusive
Hurricane Force Wind Warnings for winds 64 knots or greater

Credits | Disclaimer | Privacy Notice | Site Map | Feedback

Active Weather for the West, Warming in the East

Forecast and Warning Definitions

Forecast and Warning Definitions