A surface cold front has slipped through the I-95 corridor this morning and the Mid-Atlantic region will gradually get back to more seasonal conditions over the next 12-18 hours or so, and then we’ll take another step down in temperatures come Thursday night and Friday following the passage of another cold front; however, that air mass will modify some during the upcoming weekend and the real change in the overall weather pattern will begin early next week.
For a couple of weeks we’ve been talking about a major sudden stratospheric warming (SSW) event that has occurred at high latitudes and it has indeed set off a change of events in the atmosphere that should lead to multiple very impressive cold air outbreaks into the central and eastern US beginning early next week. Major SSW events have in recent decades generated quite dramatic turnarounds in temperature patterns for this part of the world and prospects are growing for the same kind of result this winter from this latest upper-atmospheric episode. Two such major events that bear some similarities to this year occurred during December 1984/January 1985 and December 1998/January 1999 (and they are detailed in the stratospheric warming video in our “Meteorology 101” section). The outbreak of cold air early next week should be quite widespread ranging from the Northern Plains where there will be below zero readings to the Deep South where a rare chill will develop. As far as the Mid-Atlantic region is concerned, the potential is there for temperatures to plunge to at least as low as the single digits in Philly and New York City in the next 7-10 days or so and highs could stay below freezing in DC for much of next week. Stay tuned over the next few days as we fine-tune this frigid outlook for next week and beyond.