Weather analysis – 315 pm

Wow! This is about as widespread and intense as a weather system can get here in The United States. Right now, it is still intensifying to our west. Below are surface pressures and 2-hour pressure changes.

The pressures are still falling behind the NE-moving surface low, meaning the low is deepening. The minimum pressure is falling at about 1 mb per hour, quite a significant rate. Also notice the tight pressure gradient over AL, and even tighter over MS. As air continues to try to flow from the high pressure to our east toward the low, and the pressure gradient intensifies over Alabama, winds will increase over the next few hours. So far, winds have been averaging 20-25 mph, with gusts to 41 mph at BHM, and 47 mph in Tuscaloosa. And these winds are not associated with thunderstorms. Winds will increase to 30 mph with gusts to 50 mph this evening.

Then, the thunderstorms arrive. The air is cool and fairly stable, but temperatures will cool aloft, and the wind shear is very high. The storms should move through between 5 pm (in west Alabama) and 1 am (east Alabama).

These storms will bring very heavy rain and strong gusty winds, possibly as high as 70 mph in isolated locations. Trees and powerlines could come down, and there have been reports of wind damage in Mississippi, and flash flooding. Be very careful if you head out to Christmas Eve church services or other activities tonight, since the heavy rain could cause roads to be covered with water, and the heavy rain will make visibilities low. Use common sense, and drive very carefully. It looks like the biggest threat for any tornadoes will be over extreme south Alabama.

Cold air will move in very quickly early tomorrow morning, with temperatures falling into the 30s by lunchtime. We may even see a few snow flurries, but it looks like the best chance for a dusting of snow tomorrow will be in Tennessee northward. It will still be nice to see a few snowflakes in the air on Christmas morning in Alabama!

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