All signs continue to point to a major storm roaring up the east coast Monday night and Tuesday and it should result in a substantial snowfall for the I-95 corridor from DC-to-Boston. The “sweet spot” for heaviest snowfall amounts could end up being just to the north and west of Route I-95 where more than a foot can fall in the suburbs of the big cities. Mixing with rain or ice can become an issue to the areas just south and east of Route I-95 and there will be a sharp drop off in snowfall totals from that narrow zone to the coastline, but odds favor primarily snow in and to the north and west of the big cities. In addition to the heavy precipitation, winds will become a problem with this powerful coastal storm and power outages are even a possibility in areas with heavy, wet snow accumulations and strong wind gusts. While the brunt of the storm will be Monday night and Tuesday morning in terms of heaviest snow, there will be enough instability in the upper-levels of the atmosphere that some “wrap around” snow is quite likely later Tuesday and Wednesday that can add some accumulations to the totals. It stays very cold following the storm on Wednesday and Thursday as well and, believe it or not, there could be another threat of snow for next weekend.
It stays cold, but dry right through the day on Monday at which time low pressure will be dropping southeastward through the Ohio Valley. By late Monday night, a coastal low will begin taking over as the primary low probably right near the Outer Banks of North Carolina. This low will intensify rapidly as it turns northeast likely reaching a position off the Delaware coastline come early Tuesday morning (inland solution for the storm track is less likely). The upper level features that will help spawn this major and slow-moving system will eventually coalesce into one deep upper-level trough in the Northeast US. The likely arrival time for the snow in the Mid-Atlantic's I-95 corridor on Monday night is as follows: DC metro region 5-9pm, Philly metro region 7-11pm, NYC metro region 9pm-1am. Preliminary snowfall estimates are as follows: DC metro region 8-14 inches, Philly metro region 10-16 inches, NYC metro region 12-18 inches. Winds should persist out of the Northeast during the storm and could gust to 30 mph in DC, 40 mph in Philly and 50 mph in NYC (even higher gusts likely at coastal areas).
Check back to the web site for updates as this is a complicated storm and a slight shift in track can make a big difference. The last great snowstorm during the month of March for much of the Mid-Atlantic region was the "Storm of the Century" in March 1993.
Meteorologist Paul Dorian