Reversed wind chill at night?

[Loren Booda]

Our local weatherman assured his audience that although the wind chill would reduce apparent temperature during that day, at night the wind would actually seem to warm a body.

I am assuming he was not referring to an incoming warm front, or anything to do with cloud cover, just the perception of temperature at the skin-air interface. I guess it has something to do with humidity.

What's your take on this?

[cyby]

Hrmm.. interesting. I don't know, but I am interested in finding out - why not write your meteorologist? I have not heard of this theory before. I always thought that humidity will lower the apparent wind chill temperature...

[Tide]

cyby,

It might be related to the fact that the relative humidity increases as the temperature falls. I agree - fire off a question to the meteorologist!

[cyby]

Then doesn't that mean that as the tempature falls -> RH increases -> colder wind chill? Or am I misunderstanding you?

[russ_watters]

He's probably talking about temp vs humidity, but he's still wrong: even if its 100% humid outside, wind will still take heat from you as long as the temperature is below body temperature.

And besides - wind chill is a winter thing and in winter, humidity is virtually nonexistant.

edit: HERE (http://www.nws.noaa.gov/om/windchill/index.shtml) here is a wind chill chart. Notice that in no case does wind chill exceed ambient temp. Also, humidity doesn't factor into it because you don't sweat.

[Loren Booda]

The meteorologist was all wet.

[Tide]

russ, cyby

I agree with Russ. The only role that increasing relative humidity will play is to reduce the body's ability to cool by evaporation of perspiration.

[Tide]

The meteorologist was all wet.

Then he must have been in HOT water for him to arrive at his conclusion! :wink:

[KingNothing]

I believe your city is near water, is this correct? If yes, He's probably talking about by the coast. I know this because I'm a private pilot. Basically since during the day the sun heats the area, the land warms up faster than the water, thus the air does too, so that warm air rises. That of course lowers the pressure beneath it, so the cold air over the water moves to the land and the process repeats itself. At night, the land cools quicker, so the reverse happens. That's about the only thing I can think of. Of course, that means nothing if you don't live next to water!

[Loren Booda]

Yup. I'm within ~30 miles of the Chesapeake bay.

[russ_watters]

I believe your city is near water, is this correct? If yes, He's probably talking about by the coast. I know this because I'm a private pilot. Basically since during the day the sun heats the area, the land warms up faster than the water, thus the air does too, so that warm air rises. That of course lowers the pressure beneath it, so the cold air over the water moves to the land and the process repeats itself. At night, the land cools quicker, so the reverse happens. That's about the only thing I can think of. Of course, that means nothing if you don't live next to water! Huh - that could well be what he's talking about: sea breezes vs land breezes. But he's still wrong in calling that "wind chill" - it has nothing to do with wind chill.

[brewnog]

What's wind chill? The cooling effect of wind on the body?

[delton]

The human body produces heat to maintain a temp. of 98.5. When wind is moving over your body it's chilling power is greatly increased and can cool objects much faster. Although the air temp is the same, are bodies can be chilled much faster and have to work harder to stay warm. For more info visitThis site (http://www.accuweather.com/iwxpage/adc/help/wx_windchill.htm)

[KingNothing]

In other words, how wind feels cold. And yes, he is wrong about calling it wind chill.