There has been a major sudden stratospheric warming (SSW) event in the northern and middle latitudes during the past few weeks and it has set off a chain of events in the atmosphere that will lead to a much colder temperature pattern in the central and eastern US beginning early next week. It appears as if this change to much colder weather will be quite sustained with multiple Arctic air outbreaks, some of which will contain the coldest air in several years for many locations, and there are signs that the impact of this major SSW event may not reach its peak until late this month or during the month of February.
There are a couple of major SSW events in relatively recent history that had several similarities to this current happening. One such warming event took place during December 1984 and it impacted temperatures greatly in the central and eastern US by January 1985. A second significant upper atmospheric warming event occurred in December 1998 and it helped to flip the temperature pattern in the central and eastern US during January 1999. Both of these wintertime SSW events resulted in dramatic turnarounds in the overall temperature pattern from “well above” to "well below” normal several weeks after the initial stratospheric warming, and in both cases the temperature pattern change was rather long-lasting. This doesn’t mean that each and every day will be below normal as that will not be the case. However, it does suggest that, based on historical similarities, we could be looking at an overall below-normal temperature pattern in the central and eastern US beginning early next week and continuing right into the month of February.