Tuesday, January 29, 2008

From Spring to Winter

Today dawned like an April morning, with a clear sky, balmy air and a hint of moisture on the streets; it was 54 degrees F. By mid morning, clouds began to build, the wind shifted to the north and the temper-ature began to plunge. At noon, under gray skies, it was 32 in Columbia; at the same time, it was 19 in Kansas City and 68 in St. Louis.

The dramatic change was, of course, due to the passage of an Arctic cold front, ushered in by powerful, northwest winds. The center of the storm, moving across the northern Great Lakes region, is a "tightly wound" zone of low pressure; producing blizzard conditions in the Upper Midwest, the storm will also trigger severe thunder-storms ahead of its trailing cold front, from the Gulf Coast to the Ohio Valley. Here in central Missouri, a mix of "backside" snow and sleet is pelting the window at 2 PM and the temperature is down to 21 F; coupled with strong, northwest winds, the wind-chill sits at 7 degrees.

Such potent winter storms, energized and steered by the jet stream, tend to move quickly off to the east, allowing high pressure to build from the southwest. Though frigid air will linger through the night, we should bounce into the 30s by tomorrow afternoon. Just another round in the fickle winter weather of America's Heartland!