A significant winter storm is expected to unfold this weekend in portions of the east; it will likely bring heavy snow in excess of a foot to portions of New England, strong winds in portions of the Mid Atlantic, and the threat of severe thunderstorms and isolated tornadoes down the East Coast into the southeast. Ahead of the storm system, the National Weather Service has begun issuing Winter Storm Watches for portions of the northeast. While some computer forecast models suggest blizzard conditions are a remote possibility for other storms in the extended forecast this month, it is unlikely blizzard criteria will be met in this weekend’s storm.
Before the storm hits the northeast on Friday, a weak high pressure system will be in control. With the high in place, Friday will be a quiet and pleasant day across much of the I-95 corridor with temperatures at or above normal levels for this time of year. Mid and high level clouds will increase late in the day as the winter storm takes shape to the west.
A phasing of northern and southern stream troughs over the Great Lakes region will spur cyclogenesis over the Southeast on Friday night. This low is expected to rapidly intensify as it moves northeast late Friday night and Saturday. The primary surface low will track right through the I-95 corridor, bringing up milder, moist air from the south on its eastern side while cold northwest winds wrap around on its backside.
A surge of moderate to heavy rain will move up the east coast late Friday night into Saturday morning, with rainfall amounts of 0.75-1.0″ expected. Some locations could see rainfall amounts double that, especially in thunderstorms that could fire-up near the frontal passage associated with the system. Cold air will be locked in place across northern New England to produce only snow from this system; to the south, rain will change over to snow as the cold air wraps around behind the storm. While little to no accumulation is expected in the big I-95 cities such as Washington, Philadelphia, New York, and Boston, several inches of snow could fall just north and west. Much heavier snow will fall over interior and northern portions of New England, where 12-18″ is expected.
This will be a very windy storm as the low pressure “bombs-out” over the northeast. As the pressure drops dramatically, winds will increase through much of the East. Wind gusts to and over 40m mph are possible, with the strongest winds expected late Friday into the middle of Saturday.
In addition to strong wind gusts that could create some damage, there is also the risk of severe weather from this storm from the Mid Atlantic south. Right now, the National Weather Service’s Storm Prediction Center believes the greatest threat of severe weather from this winter storm will be across southeastern Virginia, eastern North and South Carolina, southeastern Georgia, and the northern half of Florida excluding the panhandle. Thunderstorms are possible anywhere from New Jersey south to Florida; in this area, some storms can help mix stronger winds above the surface down to the surface, leading to isolated damage issues.
The storm will rapidly pull out of the area later Saturday with only flurries lingering over northern New England on Sunday in the storm’s wake. High pressure will return again, allowing the eastern U.S. to recover from yet another mid-March winter storm.