1. Local Winter Weather Criteria

Watches/Warnings
Hazard Type	Criteria	Notes
Winter Storm Warning	Any combination below	Except Blizzard
Heavy Snow Warning	7 + inches in 12 hours; or 9 + inches in 24 hours	Values averaged across the county or impacting high population areas
Lake Effect Snow Warning	7 + inches in 12 hours	Values are more localized in snow bands
Ice Storm Warning	1/2 + inch accumulation
Blizzard Warning	3 hours or more of Snow, Wind Gusts to 35 mph +, and VSBY < 1/4 mile
Wind Chill Warning	-25°F or colder	Use the lower end of the range for the triggering threshold. For example, a forecast wind chill of -15F to -25F meets wind chill warning criteria.

Advisories
Hazard Type	Criteria	Notes
Winter Weather Advisory	Any combination below
Snow Advisory	4 to 6 inches of snow in 12 hours	Values averaged across the county or impacting high population areas
Lake Effect Snow Advisory	4 to 6 inches of snow in 12 hours	Values are more localized in snow bands
Freezing Rain Advisory	any accumulation of ice up to less than 1/2 inch
Snow and Blowing Snow Advisory	Wind gusts of 25 to 34 mph with falling snow or blowing snow occasionally reducing VSBY to 1/4 mile or less
Blowing Snow Advisory	Winds less than 35 mph with blowing snow occasionally reducing VSBY to 1/4 mile or less
Wind Chill Advisory	Values between -15°F and -24°F	Use the lower end of the range for the triggering threshold. For example, a forecast wind chill of -5F to -15F meets wind chill advisory criteria.

Forecast Criteria Exception: During early and late season storms, WFOs may issue winter weather warnings based on significant public impact events which do not meet local warning criteria. For example, if a storm (such as one with heavy, wet snow or a mixture of snow, freezing rain and sleet) is forecast to significantly affect transportation, commerce or electrical power service, then the event warrants a warning.

Wind Chill: The Wind Chill Temperature (WCT) is the air temperature at which the heat transfer rate and skin temperature would be the same in the absence of wind. The WCT represents the temperature the body feels when it is exposed to wind and cold. Prolonged exposure can lead to frostbite and hypothermia.

2. Watch, Warning, Advisory Definitions

A. Winter Watches (WSW) are issued when criteria is expected to be met in the next 12 to 60 hours.

Blizzard Watch: Conditions are favorable for a blizzard event meaning that sustained wind or frequent gusts will be greater than or equal to 35 mph accompanied by falling and/or blowing snow, frequently reducing visibility to less than 1/4 mile for three hours or more. This is a very rare Watch requiring a high level of confidence that Blizzard conditions will occur.

Winter Storm Watch: Conditions are favorable for a winter storm event meaning that heavy Sleet, heavy Snow, heavy ice, blowing snow or some combination of events will occur to meet or exceed local Winter Storm Warning criteria.

Lake Effect Snow Watch: Conditions are favorable for a lake effect snow event meaning that localized snow bands will produce enough snow to meet or exceed local Lake Effect Snow Warning criteria.

Wind Chill Watch: Conditions are favorable for wind chill temperatures to meet or exceed local Wind Chill Warning criteria of -25°F or greater.

B. Winter Warnings (WSW) are issued when criteria is occurring or is expected with the next 0 to 30 hours.

Blizzard Warning: Sustained wind or frequent gusts greater than or equal to 35 mph accompanied by falling and/or blowing snow, frequently reducing visibility to less than 1/4 mile for three hours or more.

Winter Storm Warning: Winter weather event having more than one predominant hazard (i.e., heavy snow and ice or wind) meeting or exceeding locally defined 12 and/or 24 hour warning criteria for at least one of the elements or causing get impact and public safety risk.

Lake Effect Snow Warning: Widespread or localized lake induced snow squalls or heavy showers which produce snowfall accumulation meeting or exceeding locally defined warning criteria. Lake Effect Snow usually develops in narrow bands and impacts a limited area within a zone(s).

Heavy Snow Warning: Snow accumulation are meeting or are expect to exceed locally defined 12 and/or 24 hour warning criteria (7 an 9 inches respectively).

Ice Storm Warning: Ice accumulation meeting or exceeding locally defined warning criteria (1/2 inch or more).

Wind Chill Warning: Wind chill temperatures reaching or exceeding locally defined warning criteria (-25°F or colder).

C. Winter Advisories (WSW) are issued when criteria is occurring or is expected with the next 0 to 24 hours.

Winter Weather Advisory: Winter weather event having more than one predominant hazard (i.e., snow and ice, snow and sleet, or snow, ice and sleet) meeting or exceeding locally defined 12 and/or 24 hour advisory criteria for at least one of the precipitation elements, but remaining below warning criteria.

Snow Advisory: Snowfall accumulation meeting or exceeding locally defined advisory criteria, but remaining below warning criteria (4 to 6 inches in 12 hours).

Lake Effect Snow Advisory : Widespread or localized lake effect snowfall accumulation reaching or exceeding locally defined advisory criteria, but remaining below warning criteria (4 to 6 inches in 12 hours).

Freezing Rain Advisory : Light ice accumulation (freezing rain and/or freezing drizzle) meeting or exceeding locally defined advisory criteria, but remaining below warning criteria (Trace to < 1/2 inch).

Snow and Blowing Snow Advisory : Sustained wind or frequent gusts of 25 to 34 mph (or locally defined) accompanied by falling and blowing snow, occasionally reducing visibility to 1/4 mile or less for three hours or more.

Blowing Snow Advisory : Widespread or localized blowing snow reducing visibilities to 1/4 mile or less with winds less than 35 mph.

Wind Chill Advisory : Wind chill temperatures reaching or exceeding locally defined advisory criteria, but remaining below warning criteria (-15°F to - 24°F).