ARCTIC AIR IS GONE
The temperature swings over the past week have been pretty extreme. The arctic air arrived last Thursday night, pushing temperatures and wind chills to their lowest levels of the season so far. Wind chills got down near zero Friday morning. Even Saturday, temperatures didn't get out of the 30s. Then, Sunday morning, we jumped up to near 60 degrees. And Georgetown DE jumped up to an amazing 70!
Then the arctic air returned in a hurry. In Philadelphia, we dropped from 60 degrees at 1pm Sunday to 25 at 9am Monday. That's a drop of 35 degrees in only 20 hours! And if you figure in the wind chill (and who doesn't?), the drop was 46 degrees! That's the kind of drop you see in the Plains states.
And if you haven't enjoyed the cold spell, you have reason to rejoice: we won't see air this cold for at least another week. More on that later.
A SLOWER WARMUP
We won't see temperatures jump up as fast as they went down. But we will really notice the change by the weekend. Here are the updated maps to prove it-temperatures compared to normal, from Tuesday morning to Sunday afternoon:
NOT AS WARM AS LAST CHRISTMAS
Last year, we had the warmest December ever recorded in this area-by a lot. Philadelphia reached 70 degrees on the 23rd and 24th, and got to 68 degrees on Christmas Day. The lowest temperature of the whole month was 30 degrees.
This year, the Christmas warmup will be less extreme and cover only three days. As of now, we're predicting highs of 50 Saturday, 52 Sunday, and 56 Monday and Tuesday.
COLDER FOR THE NEW YEAR
It may not last too long, but the next blast of cold air will be arriving next Friday, the 30th. Some computer models aren't as cold as others, but all show an arctic surge coming into the country. The most aggressive model is the European, which happened to predict our recent arctic blast better than any other model-by far.
Here is the EURO map of temperatures compared to normal at around 5000 feet for the morning of Dec. 31st (maps at this height are good for general weather patterns in the long-range):
That purple color over our area represents temperatures that would be almost as cold as the blast that hit us about a week ago. That's why our 10-day forecast has a high of 36 for New Year's Eve, and we're predicting upper 20s for midnight fireworks. That's about 20 degrees colder than it's going to be next Tuesday.
Any threat of rain or snow for New Year's Eve or Day? It doesn't look like it. Here is the surface map predicted by the EURO for the morning of Sat. Dec. 31st. HIGH pressure is dominating the eastern third of the country. That's a dry pattern for the East (except for the lake-effect snows near the lakes).
I'll take a closer look at January next week. It seems every time most computer models are predicting a very mild pattern in the long-range (2 weeks +), the cold finds a way to return. And the EURO keeps leading the way (so far).