Wind Chill Atmospheric Sciences 101 Weather Channel Wind

Wind Chill Atmospheric Sciences 101

Weather Channel

Wind Chill • Is a measure how you feel in the cold, taking in consideration of the influence of winds. • There a lot of misconceptions. For example, if the temperature is 35 F and the wind chill is 29 F, will water freeze?

NO!

Wind Chill The first wind chill formulas and tables were developed by Paul Siple and Charles Passel working in the Antarctic before the Second World War, and wind chill info was available by the National Weather Service in the 1970 s.

Measured cooling rates of bottles of water for various combinations of temperature and wind

Cooling rate depends on two things • Difference in temperature between bottle (or skin) and the environmental air • Wind speed, which controls how quickly cold air is mixed down to the bottle/skin, and how rapidly warm air near bottle/skin is moved away.

Led to Wind Chill Formula Estimating Loss of Heat as a Function of Temperature and Wind Speed

Wind Chill Temperature • Definition: a still-air temperature that would have the same cooling effect on exposed human skin as a given combination of temperature and wind speed • Also called wind chill index and wind chill equivalent temperature

Formula Changed in 2001 Comparison of old and new wind chill values at − 15 °C (5 °F)

Will water freeze with a temperate of 35 F and a wind chill of 30 F?

Wind Chill and Safety

Why goosebumps when cold? Makes hairs stick up to create more insulation-slows wind near skin too