Winter storm warning

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A Winter Storm Warning (SAME code: WSW) 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 36 hours. Generally, a Winter Storm Warning is issued if at least the criteria—usually between 4 inches (10 cm) to 7 inches (18 cm) or more of snow or usually 3 inches (7.6 cm) or more of snow with a large accumulation of ice is forecast. In the Southern United States, where severe winter weather is much less common and any snow is a more significant event, warning criteria are lower, as low as 1 inch (2.5 cm) in the southernmost areas. (Thus, as you go from south to north the necessary accumulations get higher.) A warning can also be issued during high impact events of lesser amounts, usually early or very late in the season when trees have leaves and damage can result. Winter Storm Warnings are issued when winds are less than 35mph; if the storm has winds above this wind speed, it becomes a Blizzard Warning.

Usually, a large accumulation of ice alone with little to no snow will result in an Ice Storm Warning, or in the case of light freezing rain, a Winter Weather Advisory, a Freezing Rain Advisory, or Drizzle Advisory.

A similar warning is issued by Environment Canada's Meteorological Service of Canada from their offices.

Prior to the 2008–09 winter storm season, there was the Heavy Snow Warning, specific for when only a heavy amount of snow was expected in the warned area. The Winter Storm Warning for Heavy Snow has since replaced it.

Types[edit]

Because of the changes with the 2008–09 winter storm season, several varieties have been noted throughout the US.

  • Winter Storm Warning for Heavy Snow (Replaced the Heavy Snow Warning)
  • Winter Storm Warning for Heavy Wet Snow (same as above, except when the snow will also be wet)
  • Winter Storm Warning for Heavy Snow and Blowing Snow (When the criteria for both a WSW for Heavy snow and a winter weather advisory for Snow and Blowing Snow are met [near-blizzard conditions])[1]
  • Winter Storm Warning for Heavy Sleet (Replaced the Sleet Warning)[2]
  • Winter Storm Warning for Heavy Snow and Ice (When both the criteria for a WSW for heavy snow and an Ice Storm Warning are met) [3]
  • Winter Storm Warning for Snow and Ice (When both the criteria for a Winter Weather Advisory for Snow and an Ice Storm Warning are met)
  • Winter Storm Warning for Sleet and Freezing Rain (When both the criteria for a Winter Weather Advisory for Sleet and an Ice Storm Warning are met)

Additionally, all of the above may also include "Strong Winds" in their title if strong winds are expected as well (ex. Winter Storm Warning for Heavy Wet Snow and Strong Winds).

  • Also, the generic term, Winter Storm Warning, may be used on its own, typically to indicate that all three winter precipitation types are expected in high amounts; however, it may be used on its own as just a generic term at the forecaster's discretion regardless of whether or not this condition is met.

Example of a Winter Storm Warning[edit]

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORTHERN INDIANA
236 PM EST MON JAN 31 2011

...POWERFUL WINTER STORM TO AFFECT THE REGION...

AN INTENSE WINTER STORM WILL MOVE THROUGH THE AREA IN TWO PHASES
BEGINNING TONIGHT AND ENDING WEDNESDAY EVENING WITH A LULL TUESDAY
MORNING. SNOW WILL DEVELOP ACROSS THE AREA EARLY THIS EVENING WITH
A MIX OF SLEET AND SNOW EXPECTED MAINLY SOUTH OF HIGHWAY 24. SNOW
ACCUMULATIONS TONIGHT WILL BE GENERALLY 2 TO 5 INCHES...WITH
LESSER AMOUNTS WHERE THE MIX OCCURS AND IN THE FAR NORTH. WINDS WILL
INCREASE EARLY TUESDAY WITH BLOWING AND DRIFTING SNOW...ALTHOUGH
THERE WILL LIKELY BE A LULL WITH THE FALLING SNOW TUESDAY MORNING
AND EARLY TUESDAY AFTERNOON.

HEAVY SNOW WITH SIGNIFICANT BLOWING AND DRIFTING IS LIKELY BY
LATE TUESDAY AFTERNOON. VERY HEAVY SNOW WILL CONTINUE TUESDAY
NIGHT INTO WEDNESDAY MORNING...ENDING BY WEDNESDAY EVENING.
SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR ARE EXPECTED TUESDAY
NIGHT. SNOW MAY MIX WITH OR CHANGE TO SLEET OR FREEZING RAIN
SOUTH OF ROUTE 24...WITH SIGNIFICANT ICING POSSIBLE. ICE
ACCUMULATIONS WILL LIKELY BE BETWEEN ONE QUARTER AND ONE HALF
INCH...WITH HIGHEST ICING POTENTIAL NEAR AND SOUTH OF A LINE FROM
MARION INDIANA TO OTTAWA OHIO. SNOWFALL AMOUNTS OF UP TO 18 INCHES
WILL BE POSSIBLE WITH THIS SYSTEM...WITH LOCALLY HIGHER AMOUNTS OF
OVER 20 INCHES NOT OUT OF THE REALM OF POSSIBILITY. THESE HIGHER
SNOWFALL AMOUNTS WILL BE ACROSS FAR NORTHERN INDIANA AND SOUTHWEST
LOWER MICHIGAN.

SUSTAINED WINDS OF 15 TO 30 MPH WITH HIGHER GUSTS...WOULD SUPPORT
WIDESPREAD BLOWING AND DRIFTING SNOW...WITH DRIFTS POTENTIALLY
REACHING SEVERAL FEET IN SOME LOCATIONS. BLIZZARD TO NEAR
BLIZZARD CONDITIONS ARE ALSO POSSIBLE IN MANY AREAS...ESPECIALLY
ACROSS FAR NORTHWESTERN INDIANA AND SOUTHWEST LOWER MICHIGAN.
VISIBILITIES COULD BE DOWN TO ZERO AT TIMES TUESDAY NIGHT AND
WEDNESDAY MORNING. TRAVEL WILL LIKELY BE DIFFICULT TO IMPOSSIBLE
IN MANY AREAS...WITH ROAD CLOSURES POSSIBLE.

LISTEN TO NOAA WEATHER RADIO OR YOUR LOCAL MEDIA FOR UPDATES ON
THIS DANGEROUS WINTER STORM...ESPECIALLY IF YOU ARE PLANNING
TRAVEL IN THE REGION.

INZ017-018-022>027-032>034-OHZ004-005-015-016-024-025-010400-
/O.UPG.KIWX.WS.A.0001.110201T0000Z-110203T0000Z/
/O.NEW.KIWX.WS.W.0001.110201T0000Z-110203T0000Z/
WHITLEY-ALLEN IN-CASS IN-MIAMI-WABASH-HUNTINGTON-WELLS-ADAMS-
GRANT-BLACKFORD-JAY-DEFIANCE-HENRY-PAULDING-PUTNAM-VAN WERT-
ALLEN OH-
INCLUDING THE CITIES OF...COLUMBIA CITY...TRI-LAKES...
SOUTH WHITLEY...FORT WAYNE...NEW HAVEN...LOGANSPORT...
ROYAL CENTER...PERU...GRISSOM AFB...MEXICO...WABASH...
NORTH MANCHESTER...HUNTINGTON...ROANOKE...BLUFFTON...OSSIAN...
DECATUR...BERNE...MARION...GAS CITY...UPLAND...HARTFORD CITY...
MONTPELIER...PORTLAND...DUNKIRK...DEFIANCE...SHERWOOD...
HICKSVILLE...NAPOLEON...DESHLER...LIBERTY CENTER...PAULDING...
ANTWERP...MELROSE...OTTAWA...PANDORA...KALIDA...FORT JENNINGS...
VAN WERT...DELPHOS...OHIO CITY...LIMA...SPENCERVILLE
236 PM EST MON JAN 31 2011

...WINTER STORM WARNING IN EFFECT FROM 7 PM THIS EVENING TO 7 PM
EST WEDNESDAY...

THE NATIONAL WEATHER SERVICE IN NORTHERN INDIANA HAS ISSUED A
WINTER STORM WARNING FOR A MIX OF SNOW...SLEET AND FREEZING RAIN...WHICH
IS IN EFFECT FROM 7 PM THIS EVENING TO 7 PM EST WEDNESDAY. THE
WINTER STORM WATCH IS NO LONGER IN EFFECT.

* TIMING...SNOW WILL DEVELOP TONIGHT. AFTER A SHORT LULL IN THE
  SNOW TUESDAY MORNING...THE SNOW WILL EXPAND IN COVERAGE AND
  INTENSITY LATE TUESDAY. SNOW MAY MIX WITH OR CHANGE TO FREEZING
  RAIN AND SLEET LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. SNOW
  WILL CONTINUE INTO WEDNESDAY AFTERNOON...ENDING WEDNESDAY
  EVENING.

* MAIN IMPACT...2 TO 5 INCHES OF SNOW WILL BE POSSIBLE BY TUESDAY
  MORNING. ADDITIONAL HEAVY SNOW AND SLEET ACCUMULATIONS OF 4 TO 8
  INCHES ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY. IF
  PRECIPITATION CHANGES TO FREEZING RAIN OR SLEET...MUCH LOWER
  SNOWFALL AMOUNTS WOULD BE EXPECTED BUT SIGNIFICANT ICING WOULD
  BE POSSIBLE WITH EXTENDED POWER OUTAGES. ONE QUARTER TO ONE HALF
  INCH OF ICE ACCUMULATION IS POSSIBLE.

* OTHER IMPACTS...SUSTAINED WINDS OF 15 TO 30 MPH WITH HIGHER
  GUSTS WOULD SUPPORT WIDESPREAD BLOWING AND DRIFTING SNOW...
  HIGHLY IMPACTING TRAVEL. THESE WINDS WOULD ALSO CAUSE TREE LIMBS
  AND POWER LINES TO FALL IF SIGNIFICANT ICING OCCURS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW...
SLEET...AND ICE ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO
POSSIBLE. THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE.

&&

$$

See also[edit]

Severe weather terminology (United States)

References[edit]

  1. ^ "Winter Storm Warning In Effect". WDOR. 2014-01-14. Retrieved 2014-04-13. 
  2. ^ "Glossary - NOAA's National Weather Service". Weather.gov. 2009-06-25. Retrieved 2014-04-13. 
  3. ^ daryl herzmann akrherz@iastate.edu. "IEM :: Valid Time Extent Code (VTEC) App". Mesonet.agron.iastate.edu. Retrieved 2014-04-13. 

External links[edit]