…See James’ complete forecast below…
Clearly, the rain was just heavy enough this morning, and the air was just dry enough at the surface, so that evaporation of some of the raindrops brought temperatures down to freezing or below (evaporation uses heat…think about what it feels like when you get out of swimming on a windy day in the summer…sometimes still cool). Most of the rain has moved into eastern Alabama now, but there are still a few patches of very light rain that may move through BHM this afternoon. Now, we need to try to figure out when temperatures are going to rise above freezing over north and central Alabama. 
Temperatures were still at or just below freezing over most of the BHM metro and most locations north and east as of 2 pm, but temperatures were above freezing, mainly eliminating travel problems, in places like Tuscaloosa and Montgomery. The most severe icing issues are in eastern and northern Alabama, where more precipitation is coming and temperatures are 28-32.
We would have thought that temperatures would have already warmed up some in the BHM area by now. Take a look at the warmer temperatures moving in at 925 mb (about 1500 ft.) and 850 mb (about 4,000 ft.)
Over BHM, it is 35 degrees (1.5 C) at 925 mb, and 39 degrees (4 C) at 850 mb, and the wind is bringing in warmer air every hour at those levels. The problem is that the wind is not blowing at the surface right now very much. If the wind starts blowing, even 5 to 10 mph, it will mix some of that air down to the surface, and get the temperatures in BHM above freezing.
The other thing is that, even though its cloudy, a little sun energy could make it through the clouds and warm things up, especially right at the ground (the roads, where it matters), and a little warmth from in the soil could work its way to the surface (tough one, since it’s been so cold lately). The fact that there have not been as many serious accidents in the past hour may indicate one of those is happening a little bit.
Bottom line…travel is still very dangerous over the BHM, ANB, and GAD areas right now, and leaving work early is probably not the best move since it will eventually warm up later. How much later we don’t know. It depends on the wind getting going, and maybe a little warming from the sun or the ground. Very tough call. Another update on the physics of this at 400 pm.
