John Malan's Weather Blog for Oct. 10, 2012

CREATED Oct 11, 2012

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MILWAUKEE - Today will be windy and seasonal with high temperatures in the Milwaukee area back to sixty degrees accompanied by a strong southwest wind.

The wind will shift back to the northwest by tonight bringing colder air back into the city by Friday.

The roller coaster temperature pattern jumps back into the sixties for Saturday and Sunday, but the only difference will be a good opportunity for showers and thunderstorms on Saturday and lingering showers on Sunday.

Today is the anniversary of the tragic fog induced automobile pile up on interstate 43 in Sheboygan County in the morning hours back in 2002, causing ten fatalities as thirty-eight vehicles were involved in the wreckage.

The fog was caused by radiation fog, typical of this time of the year and the early part of the winter season.

Fog forms when the difference between the air temperature and the dew point is less than four degrees.

Radiation fog is formed by the cooling of the land after sunset by thermal radiation or heat escaping to space in calm conditions under a clear night sky.

The cool ground produces condensation in the nearby air by heat conduction or loss.

Radiation fog occurs at night and generally dissipates shortly after sunrise, but can persist all day long during the winter months.