Saturday, January 20, 2007

No wintry mix

The storms are raging all around us. The same thing happened last week when most of Missouri was clobbered with terrible ice storms and southeast Missouri saw nothing worse than drizzly skies. Weather patterns in southeast Missouri are unlike any I've seen before. Last spring brought terrible wind storms and tornadoes, the summer was as bad as a New Orleans summer, and this fall brought almost record-breaking rainfall. Funny thing, when the rest of the county is doused with bad weather, where I am, situated between the Mississippi River and a small patch of forest, I don't see the worst of it.

Missouri's midcontinental location makes it the focal point for all kinds of weather. The "character of air" over Missouri is determined by the source: warm, humid air comes up from the Gulf of Mexico. Dry, cool air comes out of the southwest. Warm, dry air comes over the Rockies. Blasts of frigid air comes from Canada. Air masses from different regions usually stick around for 2 days before another air mass muscles in. The mercurial weather is something Missourians joke about: If you don't like the weather, wait ten minutes and it will change. There's some vague truth to it.

The county has seen a lot of rain in the past few months. Fields are flooded, the swamp is full, the bayou is full. With all the standing water in the area, the air mass above the county is cooler and more humid than normal. The storm that's raging all around us is breaking up when it hits this cool air mass. On the radar map it looks like we have a forcefield: red, yellow and green splotches everywhere but here.

Several years ago, climatologists learned that forests actually produce rain and influence weather patterns. The cooling of the air above forests causes disturbance and ultimately, rain. When the land around forests has been drastically altered, like it has been in southeast Missouri, the overall cooling effect of the forest is lessened but causes locally heavy downpours. It is estimated that tree-covered land returns to the air 10 times as much moisture as a barren area and twice as much as as areas with shrubs, grass or crops. This has a dramatic effect on weather patterns, as evidenced by the clear skies, again, tonight.

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