James Spann: Winter storm watch for Alabama on Tuesday

Published On: 01.15.18 |

By: James Spann

James Spann: Winter storm watch for Alabama on Tuesday

James Spann: Winter weather problems ahead for Alabama from Alabama NewsCenter on Vimeo.

DRY, WARMER TODAY: Before we get into the specifics about the snow situation for Alabama tomorrow, today will be a mostly sunny day with a warmer afternoon; we project a high around 50 degrees. This actually could be a bad thing; the pavement/asphalt surfaces will retain some of this heat, leading to a potential problem tomorrow. Snow will fall on the warmer surfaces, leading to melting, but with very cold air in place tomorrow (we will be in the 20s most of the day), we could see a “flash freeze” type situation that could put down a thin base of ice on road surfaces.

WINTER STORM POTENTIAL TOMORROW: There is a winter weather advisory in effect for counties served by the National Weather Service office in Huntsville, and a winter storm watch to the south for north and central Alabama, including Birmingham, Tuscaloosa, Anniston and Gadsden.

For now, the U.S. 80 corridor (Demopolis to Selma to Montgomery to Opelika) is not in the watch since only trace snow amounts are forecast, but I would keep an eye on the forecast for any potential changes later today or tonight.

A few snow flurries are possible over south Alabama late tomorrow night and early Wednesday morning.

TIMING: Snow will begin over northwest Alabama tomorrow morning between 6 and 10 a m.; the onset for Birmingham, Anniston, Gadsden and Tuscaloosa will be most likely during the afternoon.

AMOUNTS: Snow amounts are expected to be light with this event, generally less than 2 inches. Most places will see 1 inch or less. Using the Short Range Ensemble Forecast, the range is from a “boom” value of 3.2 inches to a “bust” value of a trace, or nothing more than flurries (which is always possible). The mean value is one-half inch for Birmingham.

IMPACT: Despite the light snow amounts, as discussed above, there could be major impact. The snow will fall in the wake of an Arctic front, which will drop temperatures into the 20s over north Alabama. The ice accretion process on roads is quite different in very cold air, and we could see some melting, followed by a quick freeze leading to ice and very hazardous travel. Road conditions could deteriorate very quickly as the snow begins to fall tomorrow. I don’t expect much improvement tomorrow night into Wednesday morning, when temperatures drop into the 10- to 15-degree range.

On the positive side, we expect no power outages.

WHEN WILL ROADS IMPROVE? We expect sunshine in full force Wednesday with a high between 30 and 35. Some sublimation/evaporation should help to improve travel by Wednesday afternoon, but icy spots are still possible. Wednesday night will be cold again; we drop into the mid teens by early Thursday morning. Then, we rise into the 40s Thursday afternoon with a sunny sky, and any lingering ice will melt.

CONCERNING TRAVEL: I possess no special knowledge or skill about forecasting specific road conditions in coming days (our training is in meteorology; we aren’t highway engineers). It all depends on your specific route and risk tolerance, but understand roads could be very icy and dangerous across north and central Alabama as the snow begins to fall.

STAY IN TOUCH: Remember, keep an eye on updated forecasts today and tonight as changes are very possible. If you are working with an old forecast, it is bad information.

WARMER DAYS BY THE WEEKEND: With sunshine in full supply, we rise into the 50s Friday, and there is a chance temperatures will reach 60 degrees Saturday afternoon as the weekend begins with a partly sunny sky. An approaching cold front will bring a chance of showers and thunderstorms Sunday and Sunday night; we might even have a few strong storms involved. Then, cooler air returns early next week with highs in the 50s, but nothing like the cold air coming in here tomorrow.