FRIGID AIR: Despite a sunny sky, temperatures are only in the 30s over the northern quarter of Alabama this afternoon, with low 40s along the I-20 corridor (Tuscaloosa/Birmingham/Anniston). The average high for today for Birmingham is 57.

Tonight will feature another very significant freeze; most of the official reporting stations will drop into the low 20s, but the colder spots will see teens thanks to radiational cooling (clear sky, light wind). It will be our coldest night since Feb. 10.

THE WEEKEND: The sky will stay sunny tomorrow; most places will see a high in the upper 40s. Then, we turn warmer Sunday; we reach the upper 50s with a partly sunny sky. Clouds increase Sunday night.

NEXT WEEK: The first half of the week will feature a mostly cloudy sky with some chance of rain at times Monday through Wednesday. The highest coverage of showers should come Monday and Wednesday, and afternoon highs will be in the 60s. Some spots might even touch 70 degrees Tuesday afternoon. For now it looks like rain amounts will be one-half to three-quarters of an inch, with a few spots seeing 1 inch over the three days. No risk of severe weather, and I doubt if we see much thunder.

Then an Arctic front moves through late Wednesday, followed by another shot of very cold air Thursday and Friday, with highs dropping into the 40s on these two days. Not totally out of the question we see a few snow flurries over North Alabama Wednesday night or early Thursday, but it will have no impact. The coldest morning will come early Friday (one week from today), with a low in the mid 20s.

LONG RANGE: This is an active, complex pattern, and there is absolutely no skill in forecasting weather for the Christmas weekend so far out. Apps with a “20 day” or “90 day” forecast are pretty much worthless. It is hard enough getting it right out to seven days.

POLAR VORTEX: Our friends in the national news media throw out this term with very little understanding of what it actually means. See the graphic below for the real story.

WEATHER BRAINS: You can listen to our weekly 90-minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including meteorologists at ABC 33/40.

CONNECT: You can find me on all of the major social networks:

Facebook
Twitter
Google Plus
Instagram

For more weather news and information, visit AlabamaWX.