BIRMINGHAM, Ala. (WIAT) — We are within the window of forecast certainty now. The models are coming into much better agreement, the grids the we use to fine tune the forecasts are getting smaller, and the timeline is focusing down.

All this to say, there is a high probability of snow in Alabama this weekend.

One thing that has been very consistent about this forecast is the timing of the rain Saturday into Sunday. What has been a bit more inconsistent is the depth of cold air on the back side of the rain.

Whereas the temperatures at the surface matter a lot, the temperatures at different layers of the atmosphere matter a lot more. The difference between warm air and cold air aloft is the difference between a really cold rain or sleet and some beautiful white fluffy snow.

Here is where we are now, as of 4 p.m. Friday afternoon and what we need to prepare for as we move into the weekend.

First, a warm front will bring rain and temps well above freezing starting Saturday afternoon. This rain will wash away most plans for Saturday night.

Sunday morning we will have a midnight high. That means the warmest temperature on Sunday will occur at the stroke of midnight. As the temperatures tumble throughout the say Sunday the column of air above us will be able to support more snow. The deeper the cold air, the better our chances of snow will be. I definitely think we will see rain changing over to snow, or technically, the snow will maintain and not melt into rain.

As for accumulations: I think the higher elevations and mostly east and North east Alabama will see enough to build some little Olafs. The reason for this is because the rain will be quickly moving out of east Alabama and there may not be as much time for that full rain-to-snow transition to occur. Time will be the key for those who get snow and accumulating snow at that. That said, snow will still fall in many central Alabama communities it just won’t stick.