Central Alabama’s Most Detailed Seven Day Forecast

Sunday afternoon, January 17, 2021
Forecaster: Bill Murray

Clouds thickened overnight as an upper-level disturbance approached the state, but skies have been clearing all morning, allowing for ample sunshine in most areas. The exception was South Central Alabama, where a few clouds were still moving out, and Northeast Alabama, where a few stratocumulus clouds were around. Temperatures were recovering from morning lows in the upper 20s and 30s. It was 29F this morning at Anniston, 28F at Tuscaloosa, and 35F at the Birmingham Airport. With the sun this afternoon, readings will warm into the upper 40s across the Tennessee Valley, with lower and middle 50s across Central Alabama.

PATTERN TIME: The upper air pattern across North America right now features a big ridge in the west with a large trough over the East. That shortwave trough that brought the clouds this morning will push east of Alabama tonight and a ridge will build back over the southern United States. But other disturbances passing through the trough over the Northeast U.S. will try to push a surface front through Alabama this week. That boundary, combined with copious amounts of Pacific moisture, will give us increased rain chances in the second half of the week that will move out before the weekend.

MONDAY: Monday will start out cool with lows near freezing, and some partly cloudy skies, giving way to clear skies by afternoon. It will be breezy early with an occasional wind gust to near 20 mph, but those winds will subside by noon. Afternoon readings will be in the upper 40s and low 50s. Monday night lows will be near freezing again.

TUESDAY: We will be monitoring that surface front that will be sinking into Alabam from the north, triggering a few showers by late in the day into the overnight. They should stay mostly over the Tennessee Valley and Northwest Alabama, but a few could drift into Central Alabama early Wednesday. After daytime highs in the middle and upper 50s, Tuesday night lows will be in the 30s, but warm enough for any precipitation to fall as rain. There could be some sleet mixed in at the onset though.

WEDNESDAY/THURSDAY: Wednesday looks dry and mild, with highs in the 50s as the front stalls across the area. Moisture will be feeding into Alabama from the west, so skies will be mostly cloudy. A second trough will swing into the Great Lakes by late Wednesday into Thursday, and this could energize all that moisture pooling along the front, triggering a few showers during the overnight hours. Rain will become more likely by the daylight hours on Thursday when highs could touch 60 degrees.

BEST RAIN CHANCES look to be on Friday, as moisture levels skyrocket. The atmosphere over Alabama will be like a very full glass of water, with precipitable water values approaching 250-300% of normal for this time of year. As with a real glass, it won’t take much of a disturbance to make the atmosphere spill over and rain chances will go up with any passing energy. By late Thursday night, a weak shortwave passing through the ridge will trigger more showers. The front will lift back north on Friday, bringing our best rain chances.

WEEKEND OUTLOOK: Everything should move out Friday night, leading to a nice weekend. With no airmass regime change, temperatures will continue to be seasonal, with highs in the 50s and lows in the 30s.

VOODOO TERRITORY: A progressive pattern gives us rain chances every 3 days or so out to the end of the month. Rainfall amounts over the next two weeks should total around 2 inches for most folks.

DANCING WITH THE STATS: 4.2 inches of snow yesterday at Beckley and 5.2 inches at Elkins both were record snowfalls for the date in the Mountaineer State of West Virginia.

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WEATHERBRAINS: This week, the panel will entertain Steve Weiss and Roger Edwards of the Storm Prediction Center. We will be celebrating the life of Bob Johns. Johns was a long time hero at the SPC. Check out the show at www.WeatherBrains.com. You can also subscribe on iTunes. You can watch the show live at live.bigbrainsmedia.com or on James’ YouTube Channel You will be able to see the show on the James Spann 24×7 weather channel on cable or directly over the air on the dot 2 feed.

ON THIS DATE IN 2013: A powerful upper-level low-pressure system brought snow to much of North and Central Alabama. Birmingham picked up 2.1 inches. It was an interesting setup, as a surface low preceded the 500 millibars low center by about 200 miles. The surface low, located over northern Georgia, was able to throw moisture back into the circulation of the upper low. Strong dynamic cooling caused by the decreasing pressure in the atmosphere allowed temperatures aloft to become very cold at the core of the upper low. The atmosphere was cold enough for snow crystals to form and make it all the way to the ground. Strong mesoscale forcing allowed the system to overcome a 40+ degree ground and it produced accumulating snows over much of Central and Northwest Alabama.

The cold air aloft meant temperatures dropped rapidly with height, with makes for unstable conditions. The instability led to convection. Several lightning strikes were observed and many people from Cullman County down through Walker and into Jefferson and St. Clair Counties heard thunder with the heaviest snow. Most communities picked up 1 to 3 inches of snow, but there were some higher totals; six inches fell on Straight Mountain in Blount County. There were plenty of traffic nightmares where the heavier snow fell faster than the 40F ground could melt it. One of the biggest traffic headaches was along I-65 between Cullman and Falkville; the Cullman Civic Center had to be opened up as a shelter for stranded motorists.

The clearing line followed very closely on the heels of the snow’s back edge; this allowed the sky to clear before sunset for areas along and west of I-65. Follow my weather history tweets on Twitter. I am @wxhistorian at Twitter.com.