A strong cold front will sweep through AL on Tuesday. Out ahead of it, we expect a big increase in moisture due to southerly winds ahead of the system. This, along with the cold front and upper level trough approaching, will bring increasing rain chances. A few spots will get a shower today, but showers and thunderstorms will become likely Monday and Tuesday, and rainfall amounts could be heavy in some areas, as the system moves slowly. See Wes Wyatt's post below for rainfall amounts.
Then, behind the cold front, very cool air, 15 to 20 degrees below normal for September, will move in. With a gusty north wind, temperatures by Wed morning will drop into the upper 40s as far south as BHM, and will struggle to get to 70. Thu morning lows will also be chilly.
Does the early arrival of cool air last week and this week indicate a cold winter?