Coastal Storm Possible for Friday in the Northeast...

A nearly stationary upper-low over eastern Canada has kept the weather cold across the Northeast and the Great Lakes since late last week.  Areas of vorticity rotating around this low has generated a dusting of snow last Saturday night and again last night (after midnight and during the early morning hours of today) in New York City. Very light snow that is not being detected by radar is falling now in the city at 11:30 a.m.  This pattern also produced heavy lake effect snows this past weekend across the Great Lakes.  The GFS and ECMWF models during earlier runs from last night and yesterday afternoon were not in agreement on a potential coastal storm for Friday. However, the new 12 Z GFS runs is more in line with the ECMWF that generates a coastal storm that is just inside the 40/70 benchmark which would lead to a mixed snow, sleet and rain event for the coastal sections. The EWMWF offers a colder solution that is near the 40/70 benchmarks that will produce mainly snow for the New York City metropolitan area. However, now both models are coming into agreement. The Canadian model is also developing a coastal storm that could produce snow here in the New York on Friday.  The NAM model at 12Z is forecasting that the storm does not intensify significantly and passes eastward well out to see off the Southeast coast.   
About 10 days ago, the ECMWF model generated a storm which did not materialize and the GFS correctly forecasted that a storm would develop. In any event, if the storm develops, it appears that it will be fast moving and will not be a major storm but could produce a quick, significant accumulation. Since the precipitation will arrive in the morning with the heaviest precipitation during the afternoon, it is likely that the temperature will rise above freezing producing a changeover in the city and along the coast. This pattern bears watching in the next couple of days. 
George Wright is a Certified Consulting Meteorologist for Wright Weather Consulting, LLC. George is also a meteorologist with ABC News and Cablevision News 12. Our website is WrightWeather.com.