OK. Our weather pattern is active again. The jet stream, which separates cold air to the north from warm air to the south, is now stretched across the southern U.S. With strong westerly winds going over the Rocky Mountains, upper-level disturbances, or waves in the flow, are forming every 2-3 days. Each of these waves, as it moves east, brings us a chance for rain, which we really need, so this is good news. 3 upper-level waves affect Alabama in the next week. One moves through tomorrow with a good chance for rain, maybe up to an inch according to the models. Another moves to our north, bringing us a chance for another good rain on Sunday, then a strong system moves in Christmas Eve into Christmas morning, with another chance for significant rain (1″ or more).
As far as that system that comes through on Christmas Eve…it’s still too far ahead to know what’s going to happen. The GFS indicates that the surface low will move near or NW of BHM, keeping us in the warm air for most of the precipitation. We might see a few snow flurries on Christmas Day if that model is right, but nothing significant. However, the European model hints that the system could be farther south, which could put parts of north Alabama in the cold air long enough to get a little snow by Christmas morning. The Canadian model shows little or no precipitation with this system, and seems to be the outlier now.
It will be fun to watch!
