Arctic Plunge, More Interior Northeast Snowfall, and Mid-Atlantic Icing

As we turned the calendar to the official start of meteorological winter, the month of December started out relatively seasonable with some milder stretches. Overall, it started to feel much more like winter across many locations and the month was quite active with numerous disturbances spread throughout the month. However, much like the systems in November, they were largely mixed with any snowfall favoring the interior portions of the Northeast, while many areas south of the I-95 were left with little to no snowfall. The latter part of the month was then marked by a roller coaster of temperatures as a blast of polar air raced through allowing for a brief stretch of frigid weather. Temperatures then moderated once again as we closed out December on a milder note. 

We began December with a mix of dry days and rain producing systems, the greatest of which on the 6th - 7th produced rainfall amounts of 1-2" across portions of the Mid-Atlantic and New England. Additionally, milder stretches were prominent during the start of the month with daily record high temperatures in the upper 50s - low 60s set on the 3rd and 7th across portions of the Northeast. The next couple of days were then largely quiet, outside of some ocean effect snow showers which did produce some minor accumulations across Southeast MA on the 10th. The next system, an inland tracking low, then moved into New England on the 11th which produced less than 1" of snow across Long Island, widespread amounts of 1-3" across much of Northern NJ and New England, and much higher totals across the mountains and portions of Rhode Island / Northern CT where amounts of 3-6"+ fell.

After a snow shower event across portions of MA and CT overnight into the early hours on the 14th which produced a quick dusting of snow in spots, and some additional, light ocean enhanced snow showers which occurred into the morning of the 15th across Southeastern MA, the next event, a complex Nor'Easter, arrived that same morning as a mixed bag of snow, sleet, and freezing rain. For the Mid-Atlantic, this was primarily an icing event with areas NW of I-95 in Maryland and Southeast PA seeing a coating to a tenth of an inch of ice accretion before activity changed over to all rain, although localized amounts of up to a quarter of an inch of ice did occur. Elsewhere, as this system slowly tracked up the coast on the 16th, it was the areas across the Poconos, Catskills, and Berkshires that were the winners from this storm with signficant amounts of 6"+ falling across Northeast PA, and generally more minor totals of 1-3" occurring across Northern NJ and into the Hudson Valley. However, areas across Southern NH also saw shoveable snowfall totals, and a changeover to wet snow on the backside of this system even led to minor accumulations across Eastern MA by daybreak on the 17th. Moreover, this system produced an abundance of rainfall with widespread amounts of 1.5-3" falling all along and south of the I-95 corridor. 

A retweeted photo by NWS Philadelphia of snowfall in Sparta Township, NJ during the evening of December 15th, 2022.

After a briefly tranquil stretch of weather that carried on through the winter solstice, the beginnings of what would be a very dynamic system with multi-faceted impacts arrived in the Mid-Atlantic on the morning of the 22nd. This storm system brought minor icing to portions of interior MD and PA, and accumulating snowfall of a few inches again across portions of extreme Northwestern MD and portions of the far interior Northeast on the 22nd. However, it also produced especially heavy rainfall with widespread amounts of 1.5-3.5"  across the Northeast, which led to areas of poor drainage and roadway flooding, particularly across MD and VA. This disturbance would then merge with a very potent system and cold front that was tracking across the Great Lakes region the following day. As this system across the Northeast strengthened it led to a prolonged onshore flow regime, which caused widespread moderate to even major coastal flooding all up and down the Eastern Seaboard. Then, as the backside of this system and a very strong cold front swung through the Northeast on the 23rd it produced numerous, strong wind gusts of 50 - 70 mph which led to instances of downed trees / powerlines, and power outages, with the windy conditions persisting throughout the remainder of the day. However, perhaps most impressive from this dynamic system was the plummeting temperatures that occurred behind the frontal passage as arctic air surged into the Northeast, dropping temperatures some 40 - 50 degrees across all regions by the following morning! Moreover, activity along the cold front even ended as a bit of snow, which produced minor totals up and down the I-95 corridor.

A cold stretch then ensued as this arctic plunge gained a hold on the East Coast. Many locations saw frigid conditions leading up to Christmas with high temperatures struggling into the teens to the low 20s on Christmas Eve. However, the breezy conditions also continued to persist even after the system passage causing it to feel even more brutally cold with wind chills during this cold stretch bottoming out in the negative teens and twenties! Additionally, daily record lows in the single digits were set the night of the 24th across most locations as the bitterly cold air reigned. Temperatures then began to quickly moderate following the Christmas holiday, with highs returning to more seasonable levels by the middle part of the final week of December. Additionally, quiet weather and plenty of sunshine persisted throughout much of this last week as high pressure and atmospheric ridging dominated. This set the stage for a milder stretch of weather throughout the last few days of the year with many locations setting daily record highs in the 60s on the 30th before rainy conditions returned on New Years Eve.  

NWS New York graphic showing record low temperatures set on Christmas Eve.

Overall, while there were some notable temperature swings, the month largely finished near average temperature wise. Nevertheless, there were areas across the Mid-Atlantic that did run a few degrees below normal with some spots across New England actually running a few degrees above normal. With regards to precipitation the month was very active with most spots generally 0.5-1.5" above normal, though there were spots that ran as much as 3" above normal. Conversely, given the large number of mixed / rain events, outside of the mountains and the far interior regions of the Northeast, many areas finished December 3-6" below their normal monthly snowfall with seasonal snowfall totals also in a deficit. These deficits were most notable across portions of New England, where seasonal snowfall anomalies currently top out at 10" below normal.