Snow Advisory
Encyclopedia
A Winter Weather Advisory is issued by the National Weather Service
of the United States
when a low pressure system produces a combination of winter weather (snow
, freezing rain
, or sleet
) that presents a hazard, but does not meet warning
criteria. A Winter Weather Advisory is similar to significant weather advisory, but a winter weather advisory is an official product. A similar warning is issued by Environment Canada
's Meteorological Service of Canada
offices.
The advisory criteria vary from area to area. For example, any measurable snow will constitute the advisory in Florida
, while up to 5 inches will do so in New England
. If other forms of wintry precipitation are expected, then a Winter Weather Advisory or winter storm warning can be issued, also depending on the amount of precipitation that is expected.
Prior to the 2008-09 winter season, there was the Snow Advisory, specific for when snow was the only hazard expected in the advised area. The Winter Weather Advisory for Snow has since replaced it.
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...
of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
when a low pressure system produces a combination of winter weather (snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
, freezing rain
Freezing rain
Freezing rain is the name given to rain that falls when surface temperatures are below freezing. The raindrops become supercooled while passing through a sub-freezing layer of air, many hundred feet , just above the surface, and then freeze upon impact with any object they encounter. The resulting...
, or sleet
Rain and snow mixed
Rain and snow mixed is precipitation composed of rain and partially melted snow. This precipitation can occur where the temperature in the lower part of the atmosphere is slightly above the freezing point...
) that presents a hazard, but does not meet warning
Winter Storm Warning
A Winter Storm Warning is a statement made by the National Weather Service of the United States which means a winter storm is occurring or is about to occur in the area, usually within 24 hours. Generally, a Winter Storm Warning is issued if at least to or more of snow or or more of snow with...
criteria. A Winter Weather Advisory is similar to significant weather advisory, but a winter weather advisory is an official product. A similar 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...
offices.
The advisory criteria vary from area to area. For example, any measurable snow will constitute the advisory in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, while up to 5 inches will do so in New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
. If other forms of wintry precipitation are expected, then a Winter Weather Advisory or winter storm warning can be issued, also depending on the amount of precipitation that is expected.
Prior to the 2008-09 winter season, there was the Snow Advisory, specific for when snow was the only hazard expected in the advised area. The Winter Weather Advisory for Snow has since replaced it.
Example of a snow advisory
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE GREAT FALLS MT
657 PM MST SUN DEC 9 2007
MTZ008>015-044-045-047-048-050>055-101100-
/O.CON.KTFX.SN.Y.0025.071210T1100Z-071211T0000Z/
BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL-
CASCADE-CHOUTEAU-CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-
TOOLE-LIBERTY-BLAINE-SOUTHERN ROCKY MOUNTAIN FRONT-JUDITH BASIN-
FERGUS-JEFFERSON-BROADWATER-MEAGHER-GALLATIN-
INCLUDING THE CITIES OF...DILLON...BROWNING...CUT BANK...HAVRE...
GREAT FALLS...FORT BENTON...HELENA...LINCOLN...ENNIS...SHELBY...
CHESTER...CHINOOK...CHOTEAU...STANFORD...LEWISTOWN...BOULDER...
TOWNSEND...WHITE SULPHUR SPRINGS...BOZEMAN...WEST YELLOWSTONE
657 PM MST SUN DEC 9 2007
...SNOW ADVISORY REMAINS IN EFFECT FROM 4 AM TO 5 PM MST MONDAY
FOR ELEVATIONS ABOVE 4500 FEET...
A SNOW ADVISORY REMAINS IN EFFECT FROM 4 AM TO 5 PM MST MONDAY
FOR ELEVATIONS ABOVE 4500 FEET.
PERIODS OF LIGHT SNOW ARE EXPECTED TO FALL OVER THE ROCKY
MOUNTAIN FRONT...THE CENTRAL MOUNTAINS...AND ACROSS MUCH OF
SOUTHWEST MONTANA FROM MONDAY MORNING THROUGH MONDAY AFTERNOON.
EXPECT NEW SNOW ACCUMULATIONS ON MONDAY TO RANGE FROM 2 TO
6 INCHES FOR ELEVATIONS ABOVE 4500 FEET...WHILE SNOW
ACCUMULATIONS WILL GENERALLY BE LESS THAN 1 INCH AT LOWER
ELEVATIONS. AREAS OF BLOWING AND DRIFTING SNOW WILL REDUCE
VISIBILITIES AT TIMES.
A SNOW ADVISORY MEANS THAT PERIODS OF SNOW WILL CAUSE PRIMARILY
TRAVEL DIFFICULTIES. BE PREPARED FOR SNOW COVERED ROADS AND
LIMITED VISIBILITIES...AND USE CAUTION WHILE DRIVING.
LISTEN TO NOAA WEATHER RADIO...OR YOUR LOCAL MEDIA FOR THE LATEST
UPDATES ON THIS SITUATION.
$$
Example of a winter weather advisory
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE ALBUQUERQUE NM
412 PM MDT MON OCT 13 2008
...ACCUMULATING SNOW LIKELY FOR WESTERN AND NORTHERN NEW MEXICO...
.A FAIRLY POTENT MID AND UPPER LEVEL LOW PRESSURE SYSTEM WILL
INTENSIFY OVER ARIZONA AND HEAD SLOWLY TO THE EAST TONIGHT INTO
EARLY TUESDAY. VERY MOIST AIR ACROSS EASTERN NEW MEXICO WILL BE
LIFTED NORTH AND NORTHWESTWARD OVER A CHILLY AIRMASS THAT WILL
ADVANCE TO THE SOUTH AND EAST ACROSS NEW MEXICO OVER THE NEXT 24
HOURS. THE POTENTIAL EXISTS FOR SEVERAL INCHES OF SNOW OVER THE
NORTHERN AND WEST CENTRAL MOUNTAINS...THE UPPER RIO GRANDE VALLEY
AND THE WESTERN REACHES OF THE NORTHEAST HIGHLANDS.
NMZ003-140400-
/O.NEW.KABQ.WW.Y.0016.081014T0600Z-081015T0000Z/
UPPER RIO GRANDE VALLEY-
INCLUDING THE CITY OF...ESPANOLA
412 PM MDT MON OCT 13 2008
...WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO
6 PM MDT TUESDAY...
THE NATIONAL WEATHER SERVICE IN ALBUQUERQUE HAS ISSUED A WINTER
WEATHER ADVISORY FOR HEAVY SNOW...WHICH IS IN EFFECT FROM MIDNIGHT
TONIGHT TO 6 PM MDT TUESDAY.
PRECIPITATION WILL GRADUALLY INCREASE IN COVERAGE THIS EVENING
AND BECOME WIDESPREAD THROUGH TUESDAY MORNING. SNOW LEVELS WILL
INITIALLY BE ABOVE 8500 FEET THEN GRADUALLY FALL TO AROUND 6500
FEET BY TUESDAY MORNING. THE POTENTIAL EXISTS FOR 1 TO 2 INCHES
ABOVE 6500 FEET...MAINLY BETWEEN EMBUDO TO NAME PUEBLO INCLUDING
CHIMAYO. LESSER SNOW AMOUNTS AROUND A DUSTING ARE POSSIBLE IN THE
VALLEY FLOOR.
A WINTER WEATHER ADVISORY FOR SNOW MEANS THAT PERIODS OF SNOW WILL
CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR SNOW COVERED
ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILE DRIVING.
$$
DPORTER/GUYER/CHJ