12:50 PM | ****Blizzard watch already posted for DC, Baltimore, other areas likely to follow****

12Z GFS total snowfall from upcoming storm; map courtesy "stormvistawxmodels.com", Capital Weather Gang

Major storm

Confidence continues to grow for a major - and perhaps widespread crippling storm - for the Mid-Atlantic region from later Friday into early Sunday morning.  The DC National Weather Service has already posted a blizzard watch for the DC and Baltimore metro regions for Friday afternoon into Saturday night.  NOAA’s 12Z NAM and GFS computer forecast models are out and continue to show a major storm for the I-95 corridor.  The 12Z Euro has edged the heavy snowfall zone slightly farther to the north in its latest model run .  It looks like it'll be a high-impact and long-lasting storm that has the potential to dump 1-2 feet of snow on the I-95 corridor region from DC-to-Philly-to-New York City.  It is quite likely that somewhere in the Mid-Atlantic region there will be 30+ inches of snow accumulation from this upcoming system by the time early Sunday morning rolls around.  In fact, the latest GFS model run suggests 30+ inches are possible in and around the DC metro region (see GFS snowfall map above, Canadian forecast map is below). 

This storm is likely to include some serious blowing and drifting, coastal flooding and beach erosion given the sustained strong winds and full moon, and perhaps even some thunder snow and lightning.  Wind gusts could reach 70 mph at coastal locations by later Saturday and 50 mph at inland areas.  There is a chance for a changeover to or a mixing with rain and/or sleet for awhile during this storm; primarily, to the south and east of the big cities.  One other note, given the expected long-period of strong winds and the possible mixture in some areas of snow and rain, power outages are a concern as the weight may be too much for some tree limbs.  Stay tuned for updates, prepare – looks like this could be one of the all-time greats.    

12Z Canadian model total snowfall forecast map for upcoming storm; courtesy Weather Bell Analytics

Teaser snow event tonight

There is quite likely going to be a period of snow tonight across the DC and Philly metro regions as a weakening disturbance passes through the Mid-Atlantic.  A coating to an inch can actually accumulate tonight in the DC metro region and perhaps a dusting in and around Philly.  The system pretty much falls apart before it ever reaches the NYC metro region so nothing more than flurries are expected there. 

Meteorologist Paul Dorian

Vencore, Inc.