The new weather model data from the morning runs are mostly in, and it doesn’t change our thinking about Tuesday’s snow potential.

The Storm Prediction Center plots various model output for the total snowfall at Birmingham, and it looks like this:

There is a range from one-half inch to 3.5 inches, with the mean around 1.75 inches. That corresponds well with our boom/bust forecast based on Birmingham, with a boom amount of 4 inches (the upper-end amount we are forecasting) to a bust forecast of one-quarter inch (the lower end).

Here is the new deterministic Global Forecast System snowfall map:

And the European model:

Here is our forecast map:

TIMING: Rain will reach northwestern Alabama by 10 p.m. or so and change over to snow shortly after midnight. The rain band will slide southeastward overnight, reaching I-59 around 3 a.m. and changing to snow around 4-5 a.m. The snow should be over by noon in the I-59 corridor, earlier in places like Hamilton, Jasper and Cullman. It will be out of east Alabama by mid-afternoon.

IMPACTS: Roads will become snow-packed and icy with the heavy burst nature of the snow. Travel will become hazardous shortly after midnight tonight over northwestern sections and through the pre-dawn hours as the band slides southeastward. It will be a slippery commute in places like Tuscaloosa, Birmingham and Gadsden. Road conditions will become hazardous all across the winter storm warning and winter weather advisory areas during the snow. There may be some melting as the sun comes out, but with rapidly falling temperatures late Tuesday afternoon and evening, moisture on roads will freeze.

WINTER STORM WARNING/WINTER WEATHER ADVISORY: Here are current warnings and advisories from the National Weather Service:

For more weather news and information from James Spann, Bill Murray and other members of the James Spann team, visit AlabamaWx.