Clouds, Sun, The Wedge, and a Cold Front

Posted on: 2:21 pm, February 22, 2013, by

The title is complicated enough, but trying to pinpoint temperatures for a complex weather day like this over a geographic region the size of the Tennessee Valley can be a real head-scratcher.

The sun has been shining in Franklin, Lawrence, Winston, Colbert and Lauderdale Counties for at least an hour or more today, but there has been precious little sun east of I-65 through Cullman, Morgan, Madison, Limestone, Jackson, Marshall, DeKalb, most of East Alabama and Southern Tennessee.

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That lack of sunshine, combined with a wedge of cold air locked into Northeast Alabama has kept temperatures chilly for the cloudy areas while the sunny areas surged to near 60º by 2 PM:

The wedge is actually just that: a wedge of cold, dense air blown into the region by an area of high pressure to our northeast. Warmer air riding up over it (about 5,000 to 10,000 feet off the ground) enhances the clouds; the clouds keep the air below insulated from the Sun’s energy, and it just stays cold.

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This was not unexpected for Jackson, DeKalb, eastern Marshall, Cherokee, Etowah, and Blount Counties in Northeast Alabama or in Lincoln, Moore, Marion, and, Franklin Counties in Tennessee. We did expect Madison, Morgan and Limestone Counties to be a bit warmer this afternoon, but the clouds and the wedge were just a little too much for us to reach those lower 60s as anticipated.

More rain is on the way tonight, by the way, and the weekend promises to be a little milder, but it’s still not what I’d call a warm-up. Be sure to check out the latest on the extended forecast including a chance of some light snow at WHNT.com/Weather.

-Jason
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