GFS forecast hourly temperatures
All of that cold air that James and JB have been talking about over the past couple of weeks looks like it could break loose and head south, covering much of the U.S. by late this week. We’ll get to that shortly.
A cold front is moving across Alabama right now. The temp is 45 at MSL right now, with a north wind gusting to 20 mph and a wind chill near 30. Temps at BHM will drop slowly through the 50s this afternoon, and it will be windy. After mild temperatures tomorrow and Wednesday, the stronger cold front will move through Wednesday night, bringing Arctic air. Depending on cloud cover, we may not warm up much above 40 degrees on Friday, with high temperatures staying cold (in the 40s) through next Monday. Lows at night will be below freezing into south Alabama this weekend, with lows in the lower 20s possible in north Alabama. So, if you haven’t made any winter preparations (faucets, dog houses, etc.), go ahead and make them early this week.
The models show a strong upper-level disturbance coming through Alabama Friday night, but right now it looks most likely that only a few snow flurries will fall, with no accumulation. We’ll keep an eye on this system.
It looks like temperatures will mainly be below normal next week. Getting way out there (where models are rarely correct), there is a hint that a cross-polar flow could set up by the middle of December, with a 1065 mb high pressure area in Siberia, bringing cold air from Siberia into Canada and possibly the U.S. This occurred in the cold wave of December 1989.
Here are current tempeatures across the Arctic regions (in degrees C).
Notice the large area of temperatures below -30 C, with many stations in Siberia below -40 C (-40 F)? The coldest one I could find was in NE Siberia, -50 C (-58 F).
This is the GFS forecast for surface pressure on December 15 at 00 GMT (2 weeks away).
Notice the flow from Siberia, across the pole, into North America? Also, that 1065 mb pressure indicates the very heavy, cold air, and is a pressure rarely seen. We’ll see.
