WEATHER

Significant Winter Storm Likely for NJ Thursday

By John Cifelli
NJTV News Meteorologist

20170207_fs_snowmap

– Record warmth Wednesday
– Rain to heavy snow Thursday morning
– Over 6″ likely north and central, possibly south

It’s been a nickel and dime kind of winter for New Jersey thus far. As we enter what is historically the snowiest time of the year, that’s changing in a hurry. Thursday looks to bring the biggest winter storm of the year, with accumulating snow all but locked in statewide. Some locations, particularly north and west, could be counting their snow into the double digits of inches by the time things wrap up midday Thursday.

First, we have a warm surge to talk about! You might want to break the shorts out for Wednesday. Showers will clear out by the early morning, and expect a few temperature readings all the way into the 60s in southern New Jersey as we challenge some record highs. By early afternoon, winds are switching from the north and cold air will begin to filter down from Canada and the Great Lakes. A strong area of high pressure will be building into the eastern half of the country for the latter half of the week, acting as a fresh source of cold air for our developing snowstorm to work with.

Speaking of that development — there’s a ton of upper level energy racing across the country the next three days. Today’s computer guidance really all latched onto the idea that these upper level vorticity maxima will consolidate over the mid-Atlantic, encouraging the rapid deepening of a surface low tracking west to east, just south of New Jersey. The surface low responds with a period of intense strengthening known as “bombogenesis” (it is every bit as cool as it sounds), which allows any marginal temperatures at the surface or aloft to quickly drop below freezing. The bottom line is that’s the recipe for heavy snow with record warmth the day before. In fact, strong temperature gradients are fuel to the fire for developing areas of low pressure, so Wednesday’s warmth actually has a part to play in Thursday’s snowstorm.

Snow north, and rain south begins after midnight on Wednesday. The Turnpike is a good marker for who starts out snow versus rain. South and east of the highway, there will be a period of rain before the surface low strengthens and starts the dynamic cooling process which eventually switches everyone over to snow. That should happen by daybreak. I don’t think anyone is able to travel Thursday without avoiding snow, except perhaps Cape May proper. This storm is a quick hitter. It’s roughly 12-15 hours in duration, but part of that will be spent with very heavy snow falling. Expect rates exceeding an inch an hour Thursday morning. By early afternoon things are wrapping up west to east. As the storm continues to intensify, we will stay breezy in a chilling northerly flow on the storm’s backside. Thursday night will be frigid — low teens in places looks likely overnight Thursday into Friday. The winds could be an issue along the coast, possibly briefly bringing blizzard conditions to the barrier island midday Thursday.

What could go wrong with the forecast? Some of the energy that is responsible for the timing and strength of the storm’s development isn’t even over the continental United States yet. When the energy over the eastern Pacific, south of Alaska dives across the continent, it will be better sampled and ingested by the models. If it is faster/slower or weaker/stronger than believed right now, where it is in a data sparse part of the globe, that could change things downstream in New Jersey. We’ve seen these situations before, where things come together just a few miles or a few hours later than pronged, with very different results than projected. If you looked at a national weather map tomorrow afternoon, you’d be wondering where this storm was coming from, as the radar depiction and surface pressure will not be impressive. There is plenty of time and chances for things to shake out differently, but for now confidence is high for a very significant winter weather storm Thursday.