Up to 18 inches of snow is possible by early Thursday in the high-end scenario from the National Weather Service. NWS labels that layer experimental and puts the odds of exceeding it at about 1 in 10, with its expected totals running far lower. Drivers heading north this week also face hurricane-force gusts at elevation and the first frost of the season.
Snow Totals On The Map
The heaviest band on the agency’s 72-hour high-end snowfall map, running into early Thursday, sits over the White Mountains of northern New Hampshire at 18 inches. Far northern Maine and the Adirondacks of northern New York reach 5 inches each in that run, while Colorado’s high country shows 1 to 2.
The previous high-end map had 12 inches in the same part of New Hampshire, 6 in northern Maine, 3 in the Adirondacks and an inch in Vermont’s Green Mountains.
NWS’s expected forecast, the version it considers most likely, tops out near 2 inches in northern New Hampshire. The early snow arrives as NOAA’s Climate Prediction Center gives a very strong El Niño better than a 90% chance this fall and winter, with its next update due Thursday.
How Much Snow Has Fallen So Far
Light snow fell at the Mount Washington summit station for about four hours Monday evening, followed by blowing snow and freezing fog overnight. Precipitation logged at the station since Monday morning comes to 0.11 inch of liquid, and the earliest of it, on Monday morning, fell as rain.
The NWS point forecast for the summit has no more snow through Thursday morning, when a 40% chance of showers arrives with temperatures in the low 40s. According to the Mount Washington Observatory’s higher summits forecast, snow and ice on the trails should hold until early Tuesday and then gradually melt, with traction still useful in places into early Wednesday.
Gusts On The Summit
Gusts on the summit came within a few miles per hour of 100 three hours in a row Monday night, reaching 96 mph, then 98 and 97 while the snow was still falling. An earlier NWS summit forecast, issued Monday afternoon, had allowed for gusts as high as 120 mph that night. By late Tuesday morning the top gust had slipped to 74 mph, and NWS expects gusts as high as 95 on the summit Tuesday before they ease to around 70 overnight. The observatory has a wind chill advisory in place through Tuesday evening, with wind chills as low as 15 below, and forecasts gusts up to 40 mph at trailhead level Tuesday morning.
Driving Below The Snow Line
Monday’s snow stayed above the valleys, and NWS Gray expects clear skies and light winds Tuesday night to bring widespread frost, which leaves any wet patches on Route 16 through Pinkham Notch and Route 302 through Crawford Notch at risk of freezing. A frost advisory from NWS Gray covers much of the coastal plain in Maine and parts of New Hampshire overnight into Wednesday morning, so slick spots are possible well south of the mountains too. The observatory’s forecast of gusts up to 40 mph at trailhead level Tuesday morning also covers the open stretches of those roads, so tall vehicles and anything towing may feel it.
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