The winter season is generally defined as December through February since that is the coldest 90 days of the year according to historical averages. Our temperatures across eastern North Carolina averaged between 4 and 5 degrees above normal in December. A year earlier in December, 2010, the average was about 9 degrees below normal. Consequently, our temperatures during the past December were about 13 degrees warmer than the previous one. No wonder the cold air that has slapped us over the past couple of days has more of a jolt than usual.
The larger question is what can we expect for the next two months of our winter season? The answer is not simple since there are so many factors to consider. We have not seen the usual blocking high near Greenland than can force cold air southward into the East Coast. There are some hints that some blocking may begin to form around the middle of January. If so, there is a chance we could have a period of below normal temperatures during the last half of the month. If the blocking fails to develop, we'll continue to experience periods of milder weather followed by a cold shot of air for a couple of days. However, we would not see extended periods of colder conditions.
For now I think we'll continue to see near normal temperatures through mid-January with oscillating periods of warmth and cold. Somewhere around the middle of January I feel there is a better than even chance that we'll see a more extensive period of cold that will continue into early February. The bottom line is that our January temperatures should average near normal or slightly below when all is said and done. We should also see more storminess across the Southeast and that will give us a better chance for rain as the month wears on. We could even have a couple of shots at frozen precipitating if the more extensive cold arrives after mid-January.
I'll continue to monitor the movement of the cold air masses and give another update around the middle of the month.