As I wrote the other night, this system looks a lot like the one on February 1, 2007 in Huntsville, in which the precipitation started out as snow, changed briefly to freezing rain, then all rain. I thought that scenario might be a little farther south, but it may be about the same.
All kinds of physical processes will be competing as the precipitation moves in tomorrow afternoon. At 850 mb, the level which is a good indicator of whether the precipitation will fall as snow or rain, the air will be very dry tomorrow before the precipitation starts. Evaporation and melting will bring the temperature down (the wet-bulb at noon at 850 mb is -2 to -3 C), but the southeast flow will be warming the air from the southeast. The models indicate right now that the precipitation may begin as a brief period of light snow tomorrow afternoon, but significant accumulations are not expected since surface temperatures will be above freezing. By 9 pm, the precipitation should be all rain in BHM, and the same thing for north Alabama by 11 pm.
So, while we may see some snow flakes tomorrow afternoon, even in BHM, it won’t be a big travel problem.
Very cold air will come in over the weekend, with highs Saturday only near 32, and wind chills during the day in the 20s. Temps will stay cold into next week.
