National Weather Service United States Department of Commerce

Major Winter Storm System Will Bring A Variety Of Impacts To The Central, Southern, And Eastern U.S. Through The Weekend

An impactful winter storm will track from the Plains to New England through Sunday, with bitter cold behind it. Heavy snow is likely from the Corn Belt to interior Northeast, with significant ice accumulations in the Ohio Valley and New England. Farther south, heavy rain could lead to flooding in the Tennessee Valley on Saturday, with isolated severe thunderstorms in the lower Mississippi Valley. Read More >

Back to Main Page 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
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