WINTER STORM WARNING: A winter storm warning is in effect today for areas along and south of a line from Thomasville to Montgomery to Opelika. North of the warning, there is a winter weather advisory as far north as Eutaw, Centreville, Pelham, Talladega and Anniston. National Weather Service Birmingham added a few counties to the advisory early this morning — Shelby, Talladega, Calhoun and Cleburne.

Temperatures will stay below freezing across most of the state today as Arctic air remains in place and a surface low continues to form in the northwest Gulf of Mexico. Here are the key messages on what to expect:

• There are echoes on radar before sunrise this morning, but that precipitation is not reaching the ground due to very dry air in the lower levels.
• Snow will begin to reach the ground later this morning over southwest Alabama as the column becomes saturated, then become widespread across the southern counties of the state during the afternoon and evening. Snow amounts in the winter storm warning area will be generally 2-3 inches, with locally heavier amounts. There’s a good chance this system will bring the most snow Mobile has experienced since February 1973. Where banding occurs, a few spots could see more than 4 inches somewhere between Dothan and Mobile; accumulating snow is likely for places like Gulf Shores, Pensacola and Fort Walton Beach. Panama City Beach could see some snow.

• Driving will become very hazardous across south Alabama and the Florida Panhandle today as snow will accumulate rapidly on road surfaces due to the very cold air in place. The snow will be out of the state by 9 p.m., but icy travel will continue into Wednesday morning.
• To the north, in the winter weather advisory area across central Alabama, amounts will be much lighter (generally less than 1 inch), but in this kind of air it doesn’t take much snow for roads to become slick and dangerous.
• For now, the winter weather advisory does not include Tuscaloosa, Birmingham, Gadsden or points north. A few snowflakes are certainly possible, but for now the main travel impact is expected to be to the south. The advisory includes Sumter, Greene, Hale, Bibb, Shelby, Talladega, Calhoun and Cleburne counties, and areas to the south. But we all know winter storms can bring surprises, so watch for updates and radar trends this morning.
• Where snow accumulates, icy travel will continue through Wednesday morning. There could be some improvement Wednesday afternoon with strong January sun and temperatures just above freezing, but where moisture lingers, icy spots are very possible into Thursday morning.
• Wednesday morning will be the coldest morning of the week, with lows between 6 and 14 degrees over the northern two-thirds of the state; upper teens are likely down to the Gulf Coast.

A disturbance could bring a few flurries to north Alabama Thursday; otherwise, the weather will be dry over the latter half of the week with warmer afternoons; highs will be in the 40s by Thursday and Friday.

THE ALABAMA WEEKEND: Saturday will be dry. After a low between 18 and 25 degrees, expect a high close to 50. Clouds increase Saturday night, and some rain will likely move into the northern half of the state Sunday. The chance of rain will continue into Monday.

ON THIS DATE IN 2010: A tornado touched down in Huntsville over the northern part of Redstone Arsenal. The tornado passed over Memorial Parkway, northern sections of downtown Huntsville and Five Points before dissipating as it moved up Chapman Mountain. It was down for just over four miles, and three people were injured.