Blizzard Warnings issued ahead of major snowstorm

Forecast models have come into better agreement on a more organized snowstorm impacting the region primarily from tomorrow evening through Friday morning. Uncertainties still remain regarding specific details and whether the storm will track closer to the coast than modeled, but we have laid out some of the essential details in a public overview below.

Potential Hazards: Significant snow, with a general 6-10″ of snow expected across the region. There is the potential for snowfall amounts of 12″ or higher in the Hudson Valley, southern CT, and eastern Long Island. The cold temperatures will lead to a powdery snow, and combined with northerly winds around 20mph with gusts to near 40mph, will lead to blizzard conditions at times, particularly closer to the coast. Roadways will become quite slick, and wind chills will be in the single digits and even below zero at times during the storm. If you are out, make sure to bundle up with several layers. Travel is likely to become very difficult at times.

NAM model showing heavy snow throughout the area on Thursday night into Friday morning.

NAM model showing heavy snow throughout the area on Thursday night into Friday morning.

Timing: Light snow may break out across the region as soon as midnight and into the early morning hours on Thursday, as the initial overrunning portion of the storm begins — owing to increasing moisture moving atop a dome of cold air. However, most data is consistent in keeping the most steady overrunning precipitation to our north. Thus, although some light snow can be expected throughout the overnight, it will be intermittent and should not accumulate much. Much of the same can be expected for Thursday morning and Thursday afternoon, as light overrunning snow will remain primarily to the north — so intermittent light snow and flurries can be expected.

Conditions will start to deteriorate by later Thursday evening, with steady light to moderate snow and temperatures falling from the 20s into the teens. Moderate to at times heavy snow can be expected from 9:00pm through 7:00 or 8:00am Friday morning. During these periods of snow, expect reduced visibilities and dangerous travel. By Friday morning, snow will begin to move out but temperatures will be falling through the teens. The exact timing for the heaviest snow is still a bit uncertain — but some data is hinting at a wave of heavy snow from around 8:00pm through 11:00pm Thursday, then a bit of a lull back to light and moderate for a few hours, before the comma-head develops and wraps heavy snow back into the region later in the overnight. The chance of school closings for Friday is moderate to high at this time.

Uncertainties: The continued uncertainties stem from the eventual track of the low pressure system, associated with the mid level disturbance. Forecast models continue to struggle a bit with the eventual track of the low pressure system — and multiple low pressures which are forecast to develop near the coast.  A weaker or farther southeast track would result in lower impacts in our area.

However, models have continued to trend stronger with the northern stream piece of energy, which is phasing into our system, and forcing a deeper trough. For more technical details on this piece of energy and the overall setup, check out our technical write-up.  Owing to this, models have gradually shown a more organized storm system, with a surface low tracking closer to the coast. If this were to occur, mid and upper-level dynamics would significantly increase, and snowfall amounts would have to be increased to 8-14″, or even 10-16″, in some spots. Based on the trends in the modeling data, it is more likely that we’d have to increase our snowfall forecast than decrease it.

Stay tuned over the next few hours as more information becomes available.