Small craft advisory
Overview
 
A small craft advisory is a type of warning issued by the National Weather Service
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...

 in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, most frequently in coastal areas. It is issued when winds have reached, or are expected to reach within 12 hours, a speed marginally less than gale
Gale
A gale is a very strong wind. There are conflicting definitions of how strong a wind must be to be considered a gale. The U.S. government's National Weather Service defines a gale as 34–47 knots of sustained surface winds. Forecasters typically issue gale warnings when winds of this strength are...

 force.

The term wind advisory
Wind advisory
A Wind Advisory is generally issued by the National Weather Service of the United States when there are sustained winds of and/or gusts to over land...

is used in place of small craft advisory when winds of the same force occur at, or are forecast for, inland locations. A lake wind advisory is issued for winds just below this range, because unobstructed winds across the open waters of a lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 are normally faster than across land.

The wind speed that triggers the advisory has changed over time.
Encyclopedia
A small craft advisory is a type of warning issued by the National Weather Service
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...

 in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, most frequently in coastal areas. It is issued when winds have reached, or are expected to reach within 12 hours, a speed marginally less than gale
Gale
A gale is a very strong wind. There are conflicting definitions of how strong a wind must be to be considered a gale. The U.S. government's National Weather Service defines a gale as 34–47 knots of sustained surface winds. Forecasters typically issue gale warnings when winds of this strength are...

 force.

The term wind advisory
Wind advisory
A Wind Advisory is generally issued by the National Weather Service of the United States when there are sustained winds of and/or gusts to over land...

is used in place of small craft advisory when winds of the same force occur at, or are forecast for, inland locations. A lake wind advisory is issued for winds just below this range, because unobstructed winds across the open waters of a lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 are normally faster than across land.

The wind speed that triggers the advisory has changed over time. Until the late 1960s, the threshold was 32 to 38 miles per hour (or 28 to 33 knots). At some point, the lower limit was reduced to 23 miles per hour (20 knots). Today, however, most places have standardized on 25 to 38 miles per hour (22 to 33 knots), encompassing the combined ranges of forces 6 and 7 on the Beaufort scale
Beaufort scale
The Beaufort Scale is an empirical measure that relates wind speed to observed conditions at sea or on land. Its full name is the Beaufort Wind Force Scale.-History:...

.

Occasionally an informal lesser advisory, known as "small craft exercise caution," is issued for wind speeds lighter than those that call for a small craft advisory. Criteria for this vary in different localities; sometimes a range of 19 to 24 miles per hour (17 to 21 knots) is observed, or in some places 17 to 23 miles per hour (15 to 19 knots) may be used.

The insignia that denotes a small craft advisory is one red, triangular flag (two such flags, one placed above the other, signify a gale warning
Gale warning
A gale warning is a warning issued by weather services in maritime locations about the existence of winds of gale force or above or the imminent occurrence of gales at sea...

).

The National Weather Service does not specifically identify what constitutes a "small craft," although the United States Coast Guard
United States Coast Guard
The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...

 informally assigns the designation to boats with a total length of less than 33 feet (10 m).

The next step above these advisories is a high wind warning. All such bulletins may also be issued for areas above a particular elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....

, as wind speeds tend to increase with altitude
Altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...

 in the mountain
Mountain
Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...

s.

As of February 15, 1989, the National Weather Service retired its Coastal Warning Display network nationwide.

For over 100 years, display stations were established at yacht clubs, marinas, and Coast Guard stations to hoist flags, pennants and colored lights to warn mariners of storms at sea. The display stations were individually notified by the National Weather Service to raise the signals and again to lower them when the hazards passed. The National Weather Service paid for the visual signals; however, the display stations were operated by other agencies or volunteers. Although the Coastal Warning Display program has been formally discontinued, U.S. Coast Guard and other stations may continue to display warning signals without the direct participation of the National Weather Service.

Beginning June 1, 2007, U.S. Coast Guard formally re-established a Coastal Warning Display program at selected small boat stations which will hoist display flags to warn of small craft advisories, gale warnings, storm warnings and hurricane warnings.

The Coastal Warning Display program was de-emphasized in favor of frequently updated telephone recordings and NOAA Weather Radio. The latter covers the coastal areas of continental United States, Alaska, Hawaii, and the Mariana Islands with continuous weather broadcasts. The major shortcomings of the Coastal Warning Display program were that the displays reached only the small portion of the marine public within sight of them; it cannot convey specific information on movement, intensity, and duration; and the time required to notify the sites by individual telephone calls takes the forecaster away from critical tasks associated with the weather. Further, when users perceive them to be a full substitute for NOAA Weather Radio, other radio broadcasts, and the telephone recordings, they are actually being a disservice.

Canada

A similar warning, known as a Strong Wind Warning, is issued by Environment Canada
Environment Canada
Environment Canada , legally incorporated as the Department of the Environment under the Department of the Environment Act Environment Canada (EC) (French: Environnement Canada), legally incorporated as the Department of the Environment under the Department of the Environment Act Environment...

's Meteorological Service of Canada
Meteorological Service of Canada
The Meteorological Service of Canada , also known as "The Canadian Weather Service", is a division of Environment Canada, which primarily provides public meteorological information and weather forecasts and warnings of severe weather and other environmental hazards...

 from its different offices for the Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

, Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

, and Arctic
Arctic Ocean
The Arctic Ocean, located in the Northern Hemisphere and mostly in the Arctic north polar region, is the smallest and shallowest of the world's five major oceanic divisions...

 waters. These warnings are coordinated for the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...

 region with American neighboring offices.

Example of Small Craft Advisory


URGENT - MARINE WEATHER MESSAGE
NATIONAL WEATHER SERVICE BUFFALO NY
1015 AM EDT SAT OCT 18 2008

LAKE ONTARIO NEARSHORE WATERS FROM THE NIAGARA RIVER TO HAMLIN
BEACH-
LAKE ONTARIO NEARSHORE WATERS FROM HAMLIN BEACH TO SODUS BAY-
1015 AM EDT SAT OCT 18 2008

...SMALL CRAFT ADVISORY NOW IN EFFECT UNTIL 4 PM EDT THIS
AFTERNOON...

THE SMALL CRAFT ADVISORY IS NOW IN EFFECT UNTIL 4 PM EDT THIS
AFTERNOON.

NORTHEAST WINS OF 15 TO 20 KNOTS WILL RESULT IN WAVES OF 3 TO 5
FEET THROUGH EARLY AFTERNOON...THEN DECREASE TO 1 TO 3 FEET THIS
EVENING AS WINDS DIMINISH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SMALL CRAFT ADVISORY MEANS WINDS WILL PRODUCE WAVES 4 FEET OR
HIGHER. THIS WILL BE HAZARDOUS FOR SMALL CRAFT. INEXPERIENCED
MARINERS... ESPECIALLY THOSE OPERATING SMALLER VESSELS... SHOULD
AVOID NAVIGATING IN THESE CONDITIONS.

See also

  • Severe weather terminology (United States)
    Severe weather terminology (United States)
    This article describes the United States National Weather Service severe weather terminology. The NWS defines precise meanings for nearly all its weather terms. This article describes NWS terminology and related NWS weather scales...

  • Severe weather terminology (Canada)
    Severe weather terminology (Canada)
    This article describes Severe weather Terminology used by the Environment Canada's Meteorological Service of Canada. This article primarily describes various weather warnings, and their criteria. Related weather scales and general weather terms are also addressed in this article...

  • Gale warning
    Gale warning
    A gale warning is a warning issued by weather services in maritime locations about the existence of winds of gale force or above or the imminent occurrence of gales at sea...

  • Storm warning
    Storm warning
    At sea, a storm warning is a warning issued by the National Weather Service of the United States when winds between 48 knots and 63 knots are occurring or predicted to occur soon. The winds must not be associated with a tropical cyclone...

  • Hurricane warning

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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