At 945 pm, the cold front was located just south of I-59, from near Gadsden to Pelham, moving southeast about 40 mph.
The cold air associated with this front is behaving almost like an outflow boundary of cool air ahead of a thunderstorm, known as a “density current”. The change in temperature is so large over a short distance, the cold, dense air spreads out quickly due to its own weight, much like water spreads out if you pour it on the table.
Notice how the winds are not blowing along the isobars, but almost directly from high to low pressure.
The wind gusted to 55 mph at the Birmingham Airport at 930 pm, and numerous trees are down across Jefferson County. The high winds will move into Shelby, Bibb, St. Clair, and Etowah counties now. There will continue to be wind gusts of 40-55 mph as this front moves through Alabama over the next couple of hours. Think about putting off any driving right now, as high winds can blow trees down on your car.
The temperature will drop quickly tonight, winding up in the 20s by morning in Birmingham.