Do you know what it means when you are in a winter weather watch, advisory, or warning?


We use these terms to alert you of potentially dangerous weather conditions.

A winter storm watch is issued to give advance notice when a significant winter storm may affect your area within 18 to 72 hours. A watch will often be issued when there is still uncertainty in the path and strength of a developing winter storm. Usually the winter storm watch will be upgraded to a warning when the nature and location of the weather event become more apparent. In any case, when a watch is issued for your area, it is time to prepare for severe winter weather.

When severe winter weather is imminent or already occurring, a warning will be issued.

The most dangerous of all winter storms is the blizzard. The deadly combination of fierce winds and snow reduces visibility to near zero and creates wind chills well below zero. A blizzard warning is issued when winds of 35 miles an hour will occur in combination with considerable falling and/or blowing snow for at least 3 hours. Visibilities will frequently be reduced to less than 1/4 mile.

Winter Storm Warnings are issued for other severe winter weather, including:

  • snowfall of 6 inches or more in 12 hours or 8 inches in 24 hours,
  • a dangerous coating of ice (usually 1/4 inch thick or more),
  • 1/2 inch or more of sleet accumulation
  • and/or life-threatening wind chills reaching minus 30 or lower.
Advisories highlight weather that will cause significant inconvenience, but (if caution is exercised) should not be life-threatening. Advisories may be issued for one or several of the following conditions:
  • 3 to 5 inches of snow
  • ice accumulations less than 1/4 inch,
  • blowing snow significantly reducing visibilities,
  • hazardous drifting of snow,
  • and/or wind chills from -20 to -29 degrees Fahrenheit.
So now that we've covered all of the details, the important thing to understand about watches, warnings, and advisories, is that:
  • a WATCH means it's time to get ready,
  • an ADVISORY means that conditions are hazardous,
  • and a WARNING means the situation is life-threatening.

Warning Type

Guideline Criteria*

Winter Storm Warning

  • 6 to 8 inches of snow in 12 hours or 8 or more inches of snow in 24 hours
  • 1/2 inch or more of sleet
  • In "borderline" situations (advisory vs warning), if wind will cause widespread difficulty in keeping roads cleared, we issue a warning

Blizzard Warning

Sustained wind or frequent gusts of 35 mph or more with considerable falling/blowing/drifting snow frequently reducing visibility to less than 1/4 mile for three hours or more

Ice Storm Warning

Accumulation 1/4 inch or more of ice

Wind Chill Warning

Wind chills of -30ºF and below for a climatologically significant period of time.

   

Advisory Type

Guideline Criteria*

Winter Weather Advisory

One or any combination of the following:

  • ~3-5 inches of snow
  • snow and wind with < 1/2 mile visibility and considerable blowing and drifting,
  • sleet with less than 1/2 inch accumulation

Freezing Rain Advisory

Freezing rain/drizzle (only) with less than 1/4 inch ice accumulation (Note that if other precipitation is occurring such as sleet or snow, a winter weather advisory would be issued.)

Wind Chill Advisory

Wind chills of -20ºF to -29ºF for a climatologically significant period of time.


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