Monday, March 9, 2009

A Supercharged Low

Two low pressure zones have merged over the Central Plains, attached to a steep dip in the jet stream. This potent low, energized by the jet, is pulling up warm, humid air from the Gulf of Mexico, priming the Midwest for a violent clash of air masses.

Behind the advancing front, Arctic air will spill into the northern Plains and Upper Midwest, producing a marked contrast with the summer like soup ahead of the storm. Like a giant mixer, the central low will provide "lift," sweeping spring above winter (to its north) and winter below spring (to its south). Near its course, west and southeast winds will collide, triggering rotation in some of the thunderstorms as they slide northeastward ahead of the front.

Such conditions are expected to develop from Arkansas to Ohio by tomorrow, producing heavy rain, severe thunderstorms and tornadoes along and ahead of the front; northwest of the storm, across the Upper Midwest and Great Lakes region, a blizzard of heavy snow and high winds is forecast. Nature's battlegrounds are often violent and seldom boring.