Plain-language summary:
A significant snowstorm featuring dry,
fluffy snow will end tonight, leaving for a dry Monday and Tuesday. A major
storm will bring snow changing to rain along with strong winds, even damaging
winds in some spots, from Tuesday night into Wednesday. After a warmup
Wednesday, it will be modestly cooler for Thursday and Friday with some snow or
rain showers. Another storm is likely next weekend, with the best chance of
significant snow and ice being north of the U.S./Canada border, with it possibly
changing to rain later in the storm again in many areas. More and more cold air
will slowly reach our area from the northwest afterward, with colder, snowier storms
possible the following week.
Meteorological discussion:
A
significant snowstorm is occurring across all of northern New England and even
into southern Quebec, significantly farther north than projected a few days ago
due to the piece of energy being a bit stronger and the associated trough being
a bit more negatively tilted than earlier modeled.
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| Source: TropicalTidbits |
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| Source: TropicalTidbits |
The heaviest precipitation
and banding are still mostly to the south, though there are also a lot of
terrain modulations, with downsloped areas on the western slopes of the Green Mountains
seeing as little as 3” (8 cm) while other higher elevation locations received
up to 14” (35 cm). With cold temperatures and light winds throughout the lower
troposphere, the snow has accumulated efficiently with what moisture is
available, being dry with a snow to liquid ratio of 14:1 or higher in most
areas. This is the first snowstorm this winter to feature such dry, fluffy
snow.
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| Source: TropicalTidbits |
As the
storm pulls off tonight and winds turn to northwesterly, snow showers will end
in most areas, except along northwestern slopes of the Appalachians where additional
light snow accumulations are likely. A chilly but not very cold high pressure
sets up to the north over central Quebec Monday night, as a strengthening storm
heads into the Great Lakes on Tuesday. Southeasterly winds will strengthen on
Tuesday as the storm approaches, with snow beginning Tuesday afternoon in
eastern Ontario and Tuesday evening or night farther east. Snow will change to
rain in northwestern New York by Tuesday evening, southern Quebec to southern
Maine on south by later Tuesday night, and in northern Maine by Wednesday
afternoon, as the low pressure tracks into central Quebec and starts to occlude
and weaken. With strong southeasterly winds, precipitation amounts will be heavily
terrain-modulated, with up to 3” (75 mm) of total precipitation on the
southeastern slopes of the White Mountains, while the downsloped areas of the
northern Champlain Valley and southern/eastern St. Lawrence Valley may only see
0.3” (8 mm) of total precipitation. Snow accumulations will be heaviest in the
Laurentians and northern Maine before the changeover to rain, possibly up to 8”
(20 cm), with other areas seeing much less accumulation that will be washed
away and melted by Wednesday afternoon as temperature soar well above freezing.
The winds will be the strongest along the downsloped western and northwestern
slopes of the Adirondacks and Green Mountains, as well as along the Maine
coast, where wind gusts of 70 mph (110 kph) are possible Tuesday night into
early Wednesday morning, though the very strong winds will likely not be widespread
due to some low-level cold air ahead of the storm that will help stabilize the
lower troposphere and prevent the winds aloft from fully mixing down to the
surface. There is no arctic air immediately behind the storm, so a flash freeze
will not occur on the storm’s back side, with it not going back below freezing
until Thursday morning northwest of the Appalachians and Thursday night
southeast of the Appalachians.
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| Source: TropicalTidbits |
A
couple of weak disturbances will lead to some scattered snow or rain showers as
it turns modestly colder Thursday and Friday. An arctic air mass will then push
southward into the western and central U.S. as the -PNA favors a trough in western
North America, with another system late in the week ejecting from the Rockies
and likely make for another strengthening storm that heads into the Great Lakes.
However, a -NAO and -AO will help to push cold air from the Arctic into the
mid-latitudes in general and could thwart another big warm surge in New England
on north, perhaps forcing coastal redevelopment instead that would keep the low-level
cold air in, though this is up for debate. Still, with more cold air, there
will probably be widespread snow and perhaps ice with this storm, at least on
the front side before possibly changing to rain, despite the rather unfavorable
storm track. Areas north of the U.S./Canada border are the most likely to see significant
snow and ice.
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