Monday, March 3, 2008

A Telling Wind

Yesterday, a strong southerly wind brought summer-like conditions to Missouri; persisting throughout the day, the gusty flow produced highs in the mid seventies. Unless a hurricane is nearby (very unlikely in the Midwest), such persistent winds herald the approach of a potent cold front. Flowing from an area of high pressure to a zone of low pressure, the winds sweep northward ahead of the advancing front; the greater the pressure gradient, the stronger the winds.

The front arrived last night, accompanied by thunderstorms and heavy rain. This morning, the wind has shifted to the northwest and regional temperatures will fall through the day, from the mid thirties to the mid twenties. Snow should develop by early afternoon as the center of low pressure moves along the front, from the Southern Plains to the Mississippi Valley; 2 to 4 inches is expected in our area.

Such dramatic swings in the weather are typical of March, when spring battles with winter. By later in the month, a higher sun angle and a more northerly jet stream will tip the balance and spring will gain control.