Plain-language summary:
The incredible April snowstorm is ending, with gradual clearing and warming through Monday. During the eclipse Monday afternoon, some thin high clouds are likely in southern Quebec and Vermont, with it being almost cloudless to the east, while somewhat thicker clouds are expected over northwestern New York and eastern Ontario. It will continue to slowly warm up afterward, with two systems bringing rain from Wednesday through Saturday before it turns cooler but not particularly cold next weekend. The overall weather pattern continues to look mild afterward, though there is the possibility of a cold shot or slow-moving storm bringing cool and unsettled conditions for a few days.
Meteorological discussion:
Aside from a few snow showers in the mountains today into tonight, the incredible April snowstorm is finished. It was one of the biggest April snowstorms on record in the region, with some even lower elevations spots receiving >12" (30 cm) and some higher terrain locations receiving >24" (60 cm).
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| Source: National Weather Service |
The slowly-moving, almost vertically stacked low-pressure system that brought the snowstorm is slowly weakening and moving to the east. Residual low to mid-level moisture will still result in plenty of clouds tonight, and in northern New England away from the lower elevations, even for tomorrow, despite precipitation ending. However, as surface high pressure and upper-level ridge axis slowly approach, descent and gradual drying of the column will occur until it becomes virtually cloudless by Sunday night into Monday morning. It will also gradually warm up as the pool of cold air generated by the storm modifies and moves to the east. Initially, the snow cover will reflect the April sun away and keep temperatures cooler, but as the snow quickly melts to nothing by Monday in most areas, that effect will disappear.
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| Source: TropicalTidbits |
Then, a low-pressure system in the Great Lakes approaching from the southwest will weaken as it tries to push into the ridge will spread mid to high-level clouds during the day Monday, a little earlier than modeled a few days ago. They will first overspread northern New York and eastern Ontario Monday morning into early afternoon, and then Vermont and southern Quebec Monday evening, though the clouds are expected to thin as they move eastward. The clouds should be high and thin enough to just act as a bit of a filter for the solar eclipse in Vermont and southern Quebec, whereas they will likely be slightly thicker in northwestern New York and eastern Ontario. New Hampshire, Maine, and the Eastern Townships of Quebec will have virtually cloudless skies. With the dry air in place, temperatures will likely drop by 4-7C from before the eclipse starts to the end of totality, with it rising that much afterward, at least in areas with mostly clear skies. Somewhat cloudier areas to the west and areas outside the path of totality will see a somewhat less temperature drop and subsequent rise. High temperatures will be 10-14C in lower elevations and somewhat cooler in higher elevations.
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| Source: Tomer Burg |
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| Source: TropicalTidbits |
As the weakening low-pressure system is mostly blocked from pushing northeastward, it will remain dry in our region through Tuesday night. A dry backdoor cold front will sneak into eastern Quebec and eastern New England Monday night, but otherwise, there will be little change in the weather. The low-pressure system eventually will bring mostly cloudy skies and some showers on Wednesday. A second storm comes out of the Rockies and into the southern Plains later Tuesday into Wednesday, and then strengthens while tapping into rich Gulf of Mexico moisture. With the blocking pattern disappearing, the storm will move faster northeastward and eventually bring warmer temperatures, rain, and breezy conditions to our region as it passes well to the north over Quebec. With the southerly winds, the heaviest rain will likely be in southern facing slopes of the Appalachians and Laurentians, which will receive upslope enhancement, with somewhat less rain in the Champlain and St. Lawrence valleys due to downsloping.
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| Source: TropicalTidbits |
A colder air mass follows for the end of next week into next weekend, but with no arctic air, it will only be slightly cooler than average, with no snow expected outside the mountain summits. The cool down appears to be short-lived, and weather pattern continues to look overall mild over almost all of North America afterward, with little or no arctic air or high-latitude blocking. Also, repeated storms and upper-level troughs moving into western North America, which promotes a ridge in eastern North America. However, the ridge may be too far south to allow the warmest air to reach our region, and this also allows for the possibility of a cold shot into our region coming directly from the north the middle of the following week that could lead to a little snow in higher elevations, though this will likely be short-lived. There is also some chance, as is always the case at this time of year, for slow-moving cut-off lows to bring chilly and unsettled conditions for a few days.
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