Saturday, June 30, 2007

Rain Train

For the past two weeks, upper level low pressure has settled over west Texas and western Oklahoma, pumping a steady stream of moisture northward from the Gulf of Mexico. To the east, a dome of high pressure has kept this stream along its outer edge, steering it over eastern Texas, eastern Oklahoma and southeastern Kansas. This persitent weather pattern has produced an unending chain of thunderstorms and heavy rains across that swath, leading to widespread, historic flooding.

In the past few days, a week cold front has pushed down from the northwest, stalling out along a line from New Mexico to northern Illinois. As a result, the stream of precipitation has been directed eastward, following the border of the stalled front. Looking at the weather radar, one sees an unbroken arc of rain and thunderstorms from Houston to Wichita to St. Louis. Here in Columbia, rain has been falling for three days, recharging our creeks and wetlands. Relief from the deluge is expected in the next couple of days as Canadian high pressure sinks across the region and shuts off the moisture flow; unfortunately, for those in eastern Texas, this front is expected to pass to their northeast and rains will likely continue.