4 December 2006
I write this on the coldest night of the Winter so far. Now before you start writing me an email me that it is not Winter yet, save your bandwidth. Meteorological Winter began on the first of December.
This week is going to be cold..as a matter of fact, another surge of cold air will come through on Wednesday night. By the end of the weekend, however, the cold will slip off to the East, and milder Pacific air will return. The long range guidance has been very consistent in indicating a pattern change across North America, and I think it has the right general idea.
Long range forecasters look at something called the North Atlantic Oscillation. The NAO is a pressure pattern over the Atlantic. The negative phase tends to bring cold air into the East. We have had a negative NAO for several weeks but it is now going positive. This should bring 2-3 weeks of milder air.
Don’t make the mistake of thinking this means a mild Winter is in the offing. Some of our coldest winters started in late December after a good long mild spell. There has already been a lot of cold air already. I was visiting my family in Tulsa over the weekend and when I arrived there was 10 inches on the ground. It was so cold that it was still there when I drove back to the airport last night! (they know how to drive on it back in Oklahoma by the way!)
So enjoy the return to milder weather starting next week. It is probably only temporary!