Despite the recent Arctic cold spell, the overall temperature pattern since November here in the Mid-Atlantic region has been much milder than normal. However, an unfolding significant polar stratospheric warming event combined with some dramatic changes in the Pacific Ocean will set off a chain of events in the atmosphere that will likely lead to a major temperature pattern flip here by the end of next week. In fact, if I were to pinpoint a single day for the turnaround, and our luck to run out, it would be next Friday, the 13th of January. Of course, the truth of the matter is that this overall pattern changeover has been weeks in the making and will last for a few more weeks, but the beginning of the more sustained colder period of weather will begin late next week.
There will be some more “topsy-turvy” temperatures preceding the late week change in the overall pattern. Specifically, the sequence of events next week preceding the turnaround will likely be as follows: 1) moderately colder air moves in for the early part of the next week following a mild Saturday 2) it then gets milder again by the middle of next week 3) a significant rain event is then likely on Wednesday night and Thursday.
Finally, by Friday the 13th, much colder air will move in behind the rain storm and, while it may not be cold all of the time, the cold weather will be much more sustained during the second half of January compared to recent weeks which have featured only quick shots of cold air. Along with the change to the more sustained cold weather pattern, there will be increasing chances for significant snow during the second half of the month.