Winter Storm Fortis Continues to Impact Interior Northeast; Heavy Snow, High Wind Threat From New England Bombogenesis

Brian Donegan
Published: December 29,2016
Winter Storm Fortis is spreading snow across parts of the interior Northeast and will only intensify overnight, bringing heavy snow and strong winds to much of New England and some heavy lake-effect snow to the Great Lakes snowbelts.
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Snow began spreading across the Northeast Thursday morning, though along the Interstate 95 corridor south of Boston, rain has been the main precipitation type.
Fortis has already produced snow totals of a half foot or more in six states: Maine, Massachusetts, New Hampshire, New York, Pennsylvania and Vermont.
Thundersnow was reported in parts of Connecticut, including Litchfield, early Thursday evening, as well as near Watertown, New York. More thundersnow reports came in later Thursday evening from all across eastern Massachusetts, including the Boston metro area, as well as southeast Maine in the Portland area. As if thundersnow weren't enough, a report of thunder graupel (snow pellets) came in from Oswego, New York, from a heavy lake-effect band.
(INTERACTIVE: Driving Difficulty Map)

Current Radar, Temperatures, Winds, Conditions

Winter storm warnings have been posted from western Massachusetts to Maine, over areas likely to see the heaviest snow from Fortis. A winter storm warning is also in effect in the highest mountains of eastern West Virginia and northwest Maryland.
Lake-effect snow warnings and advisories cover parts of central and western New York, northwest Pennsylvania, northeast Ohio, the Upper Peninsula of Michigan and far northern Wisconsin.

Winter Weather Alerts

A southward plunge of the jet stream, or upper-level trough, is intensifying over the eastern half of the country. In response, an area of low pressure has developed at the surface near the Northeast coast, and will be pushed northward into far eastern Canada.
(MORE: Winter Storm Central)
This low is expected to undergo "bombogenesis," a rapid strengthening within a period of only 24 hours, Thursday night into Friday. As a result, about a 12- to 18-hour period of heavy snow and strong winds is expected over much of New England.
Here's our current forecast timeline and snow, wind forecasts for Winter Storm Fortis.

Thursday Night - Friday

Thursday Night's Forecast

• This is the time period where low pressure near the New England coast intensifies (bombogenesis).
• Snow, heavy at times, is expected over much of northern New England, particularly in northeast Vermont, most of New Hampshire and all but the immediate Maine coast.
• Thundersnow is likely in parts of New England due to the storm's rapid intensification.
• Lake-effect snow will develop in most of the Great Lakes snowbelts as even colder air filters in on the backside of Fortis.
• Both the New England snow and lake-effect snow will taper off later Friday as the low pulls northward into Canada.

(FORECAST: Erie, Pennsylvania | Concord, New Hampshire | Bangor, Maine)

Friday's Forecast

Snowfall Forecast

• Winter Storm Fortis will produce snow totals of 6 inches or more through Friday in the mountains of eastern West Virginia, as well as over a large swath of western Massachusetts, Vermont, New Hampshire and Maine.
• Over a foot of snow is possible in parts of New Hampshire and Maine, where snow rates over 1 inch per hour may occur Thursday night into early Friday morning.
• Lighter accumulations are expected the closer you get to the Interstate 95 corridor. Washington D.C., Baltimore, Philadelphia and New York City are expected to see rain. Boston may mix with snow at times, but very little accumulation is expected.
• The lake-effect snowbelts in Michigan, northeast Ohio, northwest Pennsylvania, and western and central New York could also see up to a foot of snow by Friday night.

Snowfall Forecast

Wind Forecast

• Fortis's strongest winds are expected to be along coastal Maine late Thursday night into Friday, with gusts over 50 mph possible. This could lead to some tree damage and power outages.
• Some wind gusts from 40 to 50 mph are possible along the rest of southeast coastal New England, including the Boston metro, Thursday night and early Friday morning. Some sporadic tree damage and isolated power outages are possible.
• Considerable blowing and drifting snow is expected from western Massachusetts to Maine Thursday night into early Friday. 

Wind Forecast

Be sure to check back with weather.com for updates as Fortis continues to impact parts of the Northeast.
Incidentally, "Fortis" (FOR-tis) is a Latin word for strong.

Snowfall Totals, So Far

Here's a list of the highest snowfall totals in each state from Fortis, as of Thursday evening.
Connecticut: 4 inches in Tolland
Indiana: 2.5 inches near Elkhart
Maine: 11.8 inches in Hollis
Massachusetts: 10 inches in Fitchburg
Michigan: 2.8 inches near Oshtemo
New Hampshire: 13.6 inches near Strafford
New Jersey: 2.9 inches in Wantage
New York: 6.5 inches in Phoenicia
​Ohio: 2.5 inches in Seven Hills
Pennsylvania: 6 inches in Canadensis
Vermont: 9.8 inches in Landgrove
​West Virginia: 2 inches near Cherry Grove
Wisconsin: 3 inches near Montreal

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