Advisories and Warnings
Small Craft Advisory
A Small Craft Advisory is issued by coastal and Great Lakes Weather Forecast Offices for areas included in the Coastal Waters Forecast or Nearshore Marine Forecasts.
Thresholds governing the issuance of small craft advisories are specific to geographic areas. A Small Craft Advisory may also be issued when sea or lake ice exists that could be hazardous to small boats.
There is no precise definition of a small craft. Any vessel that may be adversely affected by Small Craft Advisory criteria should be considered a small craft. Other considerations include the experience of the vessel operator, and the type, overall size, and sea worthiness of the vessel.
“Frequent gusts”are typically long duration conditions (greater than 2 hours).
Eastern United States from (ME to SC, including Lake Erie and Lake Ontario)
Sustained winds or frequent gusts ranging between 25 and 33 knots (except 20 to 25 knots, lower threshold area dependent, to 33 knots for harbors, bays, etc.) and/or seas or waves 5 to 7 feet and greater, area dependent.
Central United States from (MN to OH on the Great Lakes)
Sustained winds or frequent gusts between 22 and 33 knots inclusive, and/or seas or waves greater than 4 feet.
Southern United States from GA to TX and the Caribbean)
Sustained winds of 20 to 33 knots, and/or forecast seas 7 feet or greater that are expected for more than 2 hours.
Western United States from (WA to CA)
Sustained winds of 21 to 33 knots, potentially in combination with wave heights exceeding 10 feet (or wave steepness values exceeding local thresholds).
Sustained winds or frequent gusts of 23 to 33 knots. A small craft advisory for rough seas may be issued for sea/wave conditions deemed locally significant, based on user needs, and should be no lower than 8 feet.
Hawaii (HI), Samoa
Sustained winds 25 knots or greater and seas 10 feet or greater.
Guam and the Northern Mariana Islands
Sustained winds 22 to 33 knots and/or combined seas of 10 feet or more.
To indicate winds within the range 34 to 47 knots are forecast for the area.
To indicate winds 48 knots and above, no matter how high the speed, are forecast for the area. However, if the winds are associated with a tropical cyclone (hurricane), the STORM WARNING indicates that winds within the range 48-63 knots are forecast.
Issued only in connection with a tropical cyclone (hurricane) to indicate that winds 64 knots and above are forecast for the area.
NOTE: A "HURRICANE WATCH" is an announcement issued by the National Weather Service via press and television broadcasts whenever a tropical storm or hurricane becomes a threat to a coastal area. The "Hurricane Watch" announcement is not a warning, rather it indicates that the hurricane is near enough that everyone in the area covered by the "Watch" should listen to their radios for subsequent advisories and be ready to take precautionary action in case hurricane warnings are issued.
Special Marine Warnings
NOTE: A SPECIAL MARINE WARNING is issued whenever a severe local storm or strong wind of brief duration is imminent and is not covered by existing warnings or advisories. No visual displays will be used in connection with the Special Marine Warning Bulletin; boaters will be able to receive these special warnings by keeping tuned to a NOAA Weather Radio station or to Coast Guard and commercial radio stations that transmit marine weather information.
SUMMER THUNDERSTORMS can strike quickly and without warning so while you’re out, remember to keep your eye on the sky. If it starts to look dark and cloudy, and conditions are changing quickly, head for shore.