Chilly tonight, then light snow late Monday through Tuesday morning; then turns drier with one more cold shot and then turns milder with rain returning late Friday into Saturday; brief cooldown and then warmup afterward but then it becomes uncertain

Plain-language summary:

 

After the coldest night of the fall so far tonight, a weak and elongated disturbance will bring light snow Monday afternoon into Tuesday morning, except in Maine where it will stay dry. With marginal temperatures typical for November, the greatest accumulations will be in higher elevations. Another brief cooldown follows later Tuesday into Wednesday with dry weather, but it quickly warms up through Friday. A potentially two pieced-storm will bring a widespread light to moderate rain later Friday into early Saturday, with the chance of heavier rain in Maine. It will cool down at least briefly after that for next weekend, but it is unclear if warmth or chill dominates afterward.

 

Meteorological discussion:

 

The coldest air mass of the season is upon us with a central Canadian cold air mass with a high pressure approaching. Low-level clouds have been stubborn, especially along and northwest of the Appalachians, due to low-level moisture trapped underneath an inversion, which happens frequently in late fall. However, the clouds will gradually clear through tonight. With good radiational cooling resulting, almost everywhere will fall below 23F (-5C), with the colder hollows getting down to 10F (-12C)! However, with no snow cover and no true arctic air mass, these temperatures will still be quite far from even daily records.

 

Source: TropicalTidbits

 

Monday afternoon, a disturbance elongated in the north-south direction will move into our region. With the west-northwest flow aloft, moisture will be rather limited, leading to light precipitation amounts. Although the flow will turn to southerly just ahead of the system, the preceding cold air mass will be strong enough that precipitation will fall as snow for most areas, perhaps except the southern Champlain Valley and southwestern St. Lawrence Valley. Surface temperatures will be above freezing initially, but evaporational cooling and melting snowflakes as precipitation starts will cool it down to just above freezing. With the west-northwest flow aloft, the true mild air from the U.S. Plains will never reach our region. The lower elevations will see <1” (2.5 cm) of snow due to marginal temperatures, while up to 2” (5 cm) of accumulation is expected over the colder higher terrain. Maine and eastern Quebec will miss the precipitation, as the system weakens and jumps offshore to the Gulf of Maine.

 

 

Source: TropicalTidbits

 

 

Source: TropicalTidbits

 

A brief cooldown follows as another modestly cold central Canadian high moves in Tuesday night into Wednesday, but then the high pressure quickly moves offshore, with southerly flow on the back side leading to quickly warming temperatures and dry weather through early Friday. A northern low-pressure system moving east into northern Ontario and central Quebec later Friday will provide light to occasionally moderate rain for Friday evening and night, though the timing is a bit uncertain. There could also be a southern system in the southeast U.S. that strengthens as it moves along or just off the U.S. East Coast that could complicate the setup and lead to a Nor’easter bringing heavier rain to Maine. The modestly cold air behind the northern system will likely not meet whatever Nor’easter that forms in time to produce any significant snows in our region.

 

Source: TropicalTidbits

 

The pattern becomes rather uncertain and changeable after next weekend. There will likely be at least a brief modest cooldown and then some mild days afterward, but whether mild or chilly days dominate is questionable. There will be shots of cold air penetrating at least into the central U.S., but it's not clear if the cold air will readily spill eastward into our region.

Source: TropicalTidbits