Claire Reid
Upcoming winter weather forecasts will be missing a well-known cold weather term: "wind chill."
The National Weather Service announced it will no longer issue public-facing wind chill warnings, watches and advisories, beginning this winter. Wind chill terms have been retired to clear up confusion surrounding weather warnings for the public, said Milwaukee-Sullivan NWS office meteorologist Benjamin Sheppard.
Previously, wind chill advisories and extreme cold advisories were issued separately, with the former based on the "wind chill" calculation ― which essentially considers both the air temperature and how cold it feels to humans and animals due to wind speeds ― and the latter based on air temperatures alone.
Now, NWS will only issue cold weather advisories, extreme cold watches and extreme cold warnings, using wind chill temperatures in-house to help determine these products. These advisories will be issued whether forecasted temperatures meet the wind chill or air temperature threshold for each category:
- Cold Weather Advisory: Wind chill or temperature of -20ºF in the next 12 to 24 hours.
- Extreme Cold Watch: Wind chill or temperature of -30ºF is possible in the next 24 to 72 hours.
- Extreme Cold Warning: Wind chill or temperature of -30ºF is imminent in the next 12 to 36 hours.
Sheppard said the new guidelines are based on research indicating that both wind chill and extreme cold without wind are "equally impactful and equally dangerous" and require similar precautions.
"We came to the conclusion that having the two hazards in separate products just led to confusion in the public," he said.
All NWS offices in the country will cease to issue wind chill advisories, but category thresholds are different depending on the area of the country. The thresholds above are for the Milwaukee-Sullivan office, which covers most of southern and part of east-central Wisconsin.
Cold weather safety tips
NWS offers the following cold weather safety tips for each advisory level:
- Cold Weather Advisory: Be Aware. A Cold Weather Advisory is issued when seasonably cold air temperatures or wind chill values, but not extremely cold values, are expected or occurring. Be sure you and your loved ones dress appropriately and cover exposed skin when venturing outdoors.
- Extreme Cold Watch: Be Prepared. An Extreme Cold Watch is issued when dangerously cold air temperatures or wind chill values are possible. As with a Warning, adjust your plans to avoid being outside during the coldest parts of the day. Make sure your car has at least half a tank of gas, and update your winter survival kit.
- Extreme Cold Warning: Take Action! An Extreme Cold Warning is issued when dangerously cold air temperatures or wind chill values are expected or occurring. If you are in an area with an Extreme Cold Warning, avoid going outside. If you have to go outside, dress in layers, cover exposed skin, and make sure at least one other person knows your whereabouts. Update them when you arrive safely at your destination.
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