Winter Weather Preparedness Week continues with a basic definition of the different winter weather watches, warnings, and advisories issued by the National Weather Service during the winter months, along with a more detailed explanation regarding the criteria required for the issuing of such warnings and watches.
From the National Weather Service Forecast Office in Chicago...."The hazardous weather outlook highlights potentially dangers winter storms, high winds, and extreme cold, up to seven days in advance.
A winter storm watch means severe winter weather is possible in the next day or two. Check supplies of food and fuel.
A winter storm warning means severe winter weather conditions are imminent, occurring, or highly likely to begin in the next 12 hours. Avoid travel and stay indoors.
A winter weather advisory means weather that causes significant inconvenience, especially to motorists, is imminent, occurring, or highly likely to begin in the next 12 hours. Use caution.
The best way to get the latest winter weather information direct from the National Weather Service is by listening to NOAA Weather Radio – All Hazards. Radios are available at many electronics and department stores, through catalogs, and through the internet. They cost around $30 to $80. Weather radio broadcasts are also available at many Illinois interstate highway rest areas. "
Now, for the criteria that must be met for a watch, warning, or advisory to be issued, again, courtesy of the National Weather Service Forecast Office in Chicago.
"Winter Storm Watch - Conditions are favorable for hazardous winter weather conditions including heavy snow, blizzard conditions, or significant accumulations of freezing rain or sleet. These watches are usually issued 12 to 36 hours in advance of the event.
Winter Storm Warning - Hazardous winter weather conditions that pose a threat to life and/or property are occurring, imminent or likely. The generic term, winter storm warning, is used for heavy snow of 6 inches or greater, heavy sleet of half inch or more, or a combination of two or more of the following winter weather events; heavy snow, freezing rain, sleet and strong winds. The following event-specific warnings are issued for a single weather hazard:
Blizzard Warning - Sustained winds or frequent gusts of 35 mph or greater, considerable falling and/or blowing snow reducing visibility frequently to 1/4 mile or less for a period of three hours or more. There are no temperature criteria in the definition of a blizzard but freezing temperatures and 35 mph winds will create single digit wind chills.
Lake Effect Snow Warning - Lake effect snowfall of 6 inches or more in 12 hours or less, or 8 inches or more in 24 hours or less.
Ice Storm Warning - Accumulations of 1/4 inch or more of freezing rain.
Winter Weather Advisory - Hazardous winter weather conditions are occurring, imminent or likely. Conditions will cause a significant inconvenience and if caution is not exercised, will result in a potential threat to life and/or property. The generic term, winter weather advisory, is used for a combination of two or more of the following events; snow, freezing rain or drizzle, sleet, blowing snow."