WEATHER UPDATE: Jan. 22, 2016 at 12:30 p.m.
WHAT: Blizzard conditions, heavy snow, coastal flooding, beach erosion, high winds. Up to two feet of snow in places.
WHEN: Tonight through Sunday morning, beginning south to north, ending west to east.
The stakes have been raised as the most significant winter storm in several years is poised to directly impact New Jersey. Beginning shortly after dark in southern New Jersey, snow will spread northward throughout the night. All day Saturday, wind-whipped heavy snow will fall, with blizzard conditions likely for some and possible for all. Snow tapers off by Sunday morning, after one to two feet of snow has fallen for a large part of the state including the Philadelphia and New York City Metros. Coastal locations can expect high tides to run three to five feet above average, setting the stage for the worst flooding event in several years, along the lines of the December 1992 nor’easter.
Over the past couple of days, I’ve alluded to the difficulty this storm would have at northward/poleward progression before moving east out to sea. As recently as yesterday morning, much of the model guidance was suggesting that the forecast should focus the impact in southern New Jersey, with zero precipitation being projected for the furthest northern counties by some models. It seemed very hard to believe, that such a dynamic, powerful system would be shunted eastward without an equally powerful blocking current aloft to stand in its way and force that motion.
Overnight, this system has really blossomed. Severe thunderstorms have raked across the South, prompting tornado warnings in multiple states. The precipitation shield is expansive and NWS offices on the northern fringes are reporting that the system is overperforming. Aloft, the upper level trough is still open and broader than projected by the models that keyed in on a southern focus. In simple terms, this puppy is coming north, and it’s really juiced up.
Earlier in the week I mentioned that the best matching analog to the upper level pattern for this system was that which set up the Blizzard of 1996. As the storm unfolds, the actual surface weather similarities are remarkable. With the storm on the doorstep, the northward expansion and increase in snow totals echoes ’96. For those that remember, that was supposed to be a DC/Baltimore event earlier in the week, and the bullseye crept north as it drew closer. This weekend’s storm won’t have the same duration or intensity, but today’s developments suggest that this one is headed for it’s place in the top 10 storms all time for Philadelphia, and probably just outside that distinction for New York City.
There is still a big question mark as to the northern extent of the precipitation shield. There is very dry air to the north, and the strong bands of snow that will pound parts of New Jersey will leave those just outside the band high and dry, as sinking air to the north of the snow bands will greatly inhibit snowfall. Since yesterday, I have increased snowfall totals where I expect it to snow, but if heavy snow along the Route 78 corridor, it will diminish accumulations for those along Route 80. If the heavier snow can creep into Sussex and Passaic counties, it will be those just across the border in New York state who see the dramatic drop off. The snowstorm of Feb. 5 and 6, 2010 shows what kind of dramatic cutoff is expected. In that event, 25-inch reports were common in and around Camden County, Trenton saw eight inches, and there was barely a flake north of Route 78. The other challenge to this will be where the heaviest bands develop. Those who find themselves under the strongest snowfall bands will see incredible snowfall rates, over two inches per hour. Those bands will determine who winds up with two feet, and who nearby gets 16 inches. I do not expect a uniform distribution of snowfall totals.