Well it’s that time of year again, and we’re starting off early this year. At the beginning of November the polar vortex underwent a sudden stratospheric warming event that weakened it, which in response has caused frigid air to keep pouring into the Eastern United States from Canada. As you may have heard, precipitation has been substantially above normal over the past couple of months. We’ve already had 2 coastal systems over the past weeks and are on track for 2 more this week. This relentless pattern has kept reloading working in tandem with the sudden stratospheric, allowing for the persistent cold and wet weather across the United States, which makes you think one of these systems has to produce. Well it is becoming increasingly likely that we will see our first notable winter storm of the season Thursday night into Friday, which is uncommon for this time of year. Currently, our first coastal system is developing in the Southern States that will hug the coastline tonight into tomorrow delivering a soaking rain to our region leaving behind a key piece of energy over Texas, and a fresh injection of cold air in the Northeast. This is where things start to get interesting… The piece of energy left behind is likely to develop into an Upper Level Low that tracks northeastward toward the East Coast, developing an area of low pressure off the coast that rides up the coastline. As the storm gains latitude, there is forecasted to be a high pressure over Maine that prevents the cold air from escaping. This is called cold air damming which we see very often in the winter time. The dewpoints are also forecasted to be in the lower 20’s which can allow for evaporative cooling. Evaporative cooling is when latent heat is absorbed by heavy precipitation in the atmosphere, which in turn causes the column of air in the atmosphere to cool down to the surface. These 2 phenomenons will likely play a huge role in precipitation types throughout the region as the system approaches. AS OF RIGHT NOW, most major modeling suggests that a majority of the region will start out as snow quickly turning over to rain at the immediate coastal areas as warmer air invades. The urban corridor (NE-PA, NW-NJ, Hudson Valley) looks to stay some type of wintery precipitation for the majority of the event.
The upper level low placement will be vital as models have been trending in a more favorable in the placement of it, allowing for colder air to be kept in place meaning more wintery precipitation farther southeast and the urban corridor to stay snow for the whole event. I will get into more details tomorrow about potential snowfall accumulations as we will have a better idea of the storm setup. Get ready for Winter 2018 – 2019 everyone because it’s coming sooner than you think. Next update will be tomorrow evening.
P.S. Our last notable winter storm in November for our region was a couple weeks after Sandy in 2012 where a foot of snow fell in some counties in NJ!!!
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