Monday, April 21, 2014

Southern Appalachian Weather

You heard the adage about not liking the weather, then stick around and it will change soon? That is the fascinating world that David M. Gaffin writes about in Southern Appalachian Weather.

This book was written to understand the complexities of southern Appalachian weather. Gaffin has worked for the National Weather Service in Morristown, TN and has a lot of insights to understanding the complex weather systems that affect this region.

The southern Appalachian includes some of the oldest mountains in the world and is in the cross-hairs of two major sources of moisture: the Gulf of Mexico and the Atlantic Ocean.

Gaffin divides the region into four distinct areas: Cumberland Plateau (1500 to 3000 ft.); the Great Tennessee Valley (500 to 1500 ft.); southern Appalachian Mountains (1500 to 6500 ft.); and the Blue Ridge Mountains located on the eastern edge of the studied area. The unique topography combined with the moisture sources creates a lot of interesting weather scenarios.

Here are some of those weather situations:
  • mountains act as a heating source through solar radiation
  • temperature inversions (air cooling faster near the surface than above it) causing mountainous areas to be warmer than the valley. This happens especially with a strong southwest wind that traps cold air in the valley.
  • urban heat islands affecting the low morning temperatures in outlying areas despite little difference in elevation
  • for every 1000 feet in elevation difference, there is usually a 3.5 degree change in Fahrenheit temperature
  • valley trapping of cold air creates situations for dense fog
  • mountain heat waves create strong wind gusts.
Gaffin also describes the area's climatology affecting snow, tornadoes, lightning, flooding and more. Check out this book from your Chatt State Library and find out more about our wonderful southern Appalachian weather!

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