Why should you care about wind chill? A guide to wind chill watches, warnings and more
The metro-east will be under a wind chill warning starting at 6 p.m. Thursday, Dec. 22, through noon Friday, Dec. 23, according to the National Weather Service of St. Louis.
Brad Charboneau, a meteorologist with the NWS of St. Louis, said wind chills will fall well below zero by Thursday night, with the coldest morning being Friday, with wind chills 25- to 30-degrees below zero.
He projected Saturday’s wind chills will only get to around 0 degrees or the low single digits. Charboneau expects temperatures to break a bit and reach the mid-20s on Christmas Day, when the area finally will see some relief.
With that in mind, just what is wind chill, a wind chill watch and a wind chill warning? Here is a brief explanation of each from the National Weather Service.
Wind chill
Wind chill is a term used to describe what the air temperature feels like to the human skin due to the combination of cold temperatures and winds blowing on exposed skin. In simple terms, the colder the air temperature and the higher the wind speeds the colder it will feel on your skin if you’re outside. So even if it remains the same temperature, but the wind speed increases it will actually feel colder to your skin.
Wind chill watch
NWS issues a wind chill watch when dangerously cold 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 a half a tank of gas, and update your winter survival kit.
Difference between watch and warning is not the temps but confidence. 24 hours or longer away from the actual event. When we are reasonably confident we’ll see those values the warning is when we have higher confidence within 24 hours. Difference confidence, closer to the event, might upgrade to a warning if those conditions will happen.
Wind Chill Warning
NWS issues a wind chill warning when dangerously cold wind chill values are expected or occurring and can be life threatening. If you are in an area with a wind chill warning, avoid going outside during the coldest parts of the day. If you do 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.
The value at which the NWS issues a wind chill watch or wind chill warning, Charboneau noted,is 25 degrees below zero. In this regard, he explained the difference between the two.
“The difference between a watch and warning is not the temperatures, but our confidence in the event,” he said Thursday morning. “A watch is issued 24 hours or longer away from the actual event. When we are reasonably confident we’ll see those values the warning is issued when we have higher confidence within 24 hours of the event.”
He also noted frost bite can occur within 30 minutes in these conditions.
“It doesn’t take long at all — especially with exposed skin. It doesn’t take much time at all,” he said.