Plain-language summary:
At least partial sunshine will lead to
rapidly rising temperatures today after the cold temperatures yesterday and
last night. A little rain in southwestern areas and snow elsewhere is expected
tonight into tomorrow morning, especially over higher terrain, but amounts will
be light everywhere. A major warmup with some showers occurs Tuesday and
Wednesday, with the warmest temperatures occurring in northwestern New York west
of the Adirondacks. A sharp cold front Wednesday night into Thursday morning
will lead to a quick-hitting line of thunderstorms, along with a rapid drop in
temperatures, with a bit of snow possible at the end of the event. After a dry
and cold Thursday, it will quickly turn much warmer by next weekend and beyond,
likely with little or no precipitation. It may finally turn colder and stormier
after the first week of March, perhaps leading to late-season snow if the air
masses over Canada are still cold enough.
Meteorological discussion:
After a cold day yesterday, a rarity
this winter, southwesterly wind ahead of a moisture-starved clipper quickly
passing through northern Ontario, combined with at least partial sunshine, will
already warm it up to near or just above freezing for most of the region again
today. Tonight into tomorrow morning, the clipper will bring a little rain west
of the Appalachians and snow east of the Appalachians and in southern Quebec.
However, with the low-pressure center and dynamics going well to the north, amounts
will be very little except in higher terrain of the Laurentians and maybe Adirondacks
and Green and White Mountains, where there will be upslope enhancement, and
even there, few places will get more than 2” (5 cm). A weak high pressure noses
in briefly from northern Ontario Monday night, but the air mass will hardly be
cold at all, still warmer than average for this time of year.
 |
| Source: TropicalTidbits |
After that, a strong low pressure will
eject from the Rockies on Tuesday and quickly move northeastward through
Wednesday and Thursday. This Colorado low is associated with a -PNA
characterized by a pronounced upper-level trough in western North America and a
pronounced upper-level ridge in eastern North America. This is a classic setup
for springlike warmth to surge into our region, especially with no antecedent
cold air mass and little snow cover to provide any resistance. Warm and moist
air will simply flood in, accompanied by showers. The sharp cold front
associated with the storm will spark thunderstorms from west to east Wednesday
night, especially in northwestern New York, where it will be the warmest and most
unstable. Strong southerly winds will lead to some cooling maritime influence east
of the Adirondacks, though it will still be much warmer than average. It will
turn sharply colder behind the cold front, with the cold air arriving at the
low-levels first. If the system is elongated enough with energy lingering behind
over the Ohio Valley by Thursday, precipitation could linger just long enough
for rain to change to a brief period of snow over the region. However, with the
fast-moving nature of the system and the lack of a consolidated storm behind
the cold front, nobody will likely see >1” (2 cm) outside of the higher
terrain.
 |
| Source: TropicalTidbits |
The cold air will retreat very quickly
as another deep upper-level trough enters the western U.S., building the ridge
again in the eastern U.S. By next weekend, it will be much warmer than average
again, with high pressure and some sunshine. The ridge will be so strong that
it will deflect any big storm well to the northwest for a while, although a
weaker slow-moving storm tunneling underneath the ridge through the
mid-Atlantic U.S. could bring light rain to southern areas at some point. There
are some signs that after the first week of March, the -PNA, +NAO, and +AO
teleconnections will neutralize or even weakly change sign, allowing cooler air and more troughing to
return to the region. This could open the door to some late-season snow, if the
cold air source over Canada is still sufficiently cold then.
 |
| Source: TropicalTidbits |
 |
| Source: Climate Prediction Center |