Winter Storm Fortis to Bring Heavy Snow to Much of New England; May Undergo Bombogenesis

Brian Donegan
Published: December 28,2016
Winter Storm Fortis will bring heavy snow and strong winds to much of New England, and the Great Lakes region could see heavy lake-effect snow during the final days of 2016.
(MORE: The Science of Naming Winter Storms | 2016-2017 Winter Storm Names List)
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.
Lake-effect snow watches, 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, will intensify over the eastern half of the country beginning Thursday. In response, an area of low pressure will develop 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 along with an outlook on who may see the heaviest snow from Winter Storm Fortis.

Thursday

• Snow will spread from southwest to northeast, from the Appalachians of West Virginia and Pennsylvania to northwest New Jersey, New York state and New England.
• Mainly rain is expected along the Interstate 95 corridor from Boston to Washington D.C. and points south and east of there, due to influences from the milder ocean air. 

(FORECAST: Pittsburgh | Albany, New York | Portland, Maine)

Thursday's Forecast

Thursday Night - Friday

• This is the time period where low pressure near the New England coast intensifies (bombogenesis).
• Snow, heavy at times, is expected over virtually all of northern New England and portions of southern New England west of Boston.
• 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

Snow, Wind Outlook

• 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, New York City and downtown Boston are expected to see rain.
• Fortis's strongest winds are expected to be along coastal New England and Long Island Thursday night into Friday, with gusts over 50 mph possible. This could lead to some tree damage and power outages.
• Considerable blowing and drifting snow is expected from western Massachusetts to Maine Thursday night into early Friday. 
• 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.

Be sure to check back with weather.com for updates over the next couple of days as we fine tune the details of this forecast.
Incidentally, "Fortis" (FOR-tis) is a Latin word for strong.

Snowfall Forecast

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