Plain-language summary:
Rain in Maine, except snow in higher elevations of northwestern Maine, will end tonight, with it turning briefly warmer and drier for Monday. A line of showers will arrive Monday night, and then scattered showers will dominate Tuesday and Wednesday, with it even turning cold enough for snow on Wednesday, perhaps even at lower elevations, though accumulations will likely be limited to higher elevations. It will then briefly turn drier Thursday and then somewhat warmer Friday before likely rain on Saturday before a likely drier cooldown for a couple of days afterward. Warmth may become more dominant in late April, though confidence is not particularly high on this scenario yet.
Meteorological discussion:
Nor'easter brings rain and snow to Maine today, dry elsewhere
A weak Nor'easter that brought wet snow from southern Vermont to southern Maine yesterday morning had weakened and slowly moved northeastward, leading to a weakening or dissipation of precipitation afternoon. However, the Nor'easter is slowly strengthening again, now in the Gulf of Maine, leading to moderate to heavy precipitation in Maine, mostly rain but also wet snow in northwestern Maine with a small slushy wet accumulation possible. This slow-moving storm has been tricky to predict, as is often the case with coastal and/or slow-moving storms, with models struggling on the details all week long. Areas to the west will stay dry today but mostly cloudy, except areas northwest of the St. Lawrence River, which will see more sunshine.
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| Source: TropicalTidbits |
Warmer and drier briefly Monday, showers Monday night through Wednesday, with even snow mixing in on Wednesday even at lower elevations but accumulations mostly at higher elevations
The Nor'easter will finally move completely out of the way by tomorrow, with ridging briefly taking over leading to warmer, even slightly above average temperatures, with some sunshine, making it feel truly springlike. However, another storm will already be pushing into the Great Lakes from the west, and it moves into central Quebec Monday night, it will bring scattered showers associated with the weak cold front, moving west to east. Cold air aloft (though not as cold as last week) follows for Tuesday and Wednesday as an upper-level trough deepens in the eastern U.S. again, a downstream response to the upper-level ridging in western North America (+PNA) that has been a little more persistent than models originally indicated. Initially on Tuesday, the cold air aloft along with lingering moisture will lead to surface-based instability and convective showers along a secondary cold front, with the low-level cold air lagging behind the second front and the April sun doing its best to heat up the low-levels. The low-level cold air will push in by Wednesday, and with the upper-level trough still overhead, scattered rain and snow showers are likely, with snow likely mixing in even at lower elevations at night and early in the morning through Wednesday night. This cold air mass is not as cold as last week's cold air mass, with low elevations staying near or above freezing with little if any snow accumulation. However, higher terrain could see up to 6" (15 cm) or snow, especially along and just northwest of the Appalachians, such as the Adirondacks, Green Mountains, and White Mountains, where both colder temperatures and upslope enhancement of precipitation will contribute to the snow accumulations.
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| Source: TropicalTidbits |
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| Source: Climate Prediction Center |
Turns briefly drier Thursday and then somewhat warmer Friday, then possible rain on Saturday before another possibly drier cooldown for a couple of days
The cold air will modify Thursday and Friday with drier conditions, and it will feel springlike on Friday when the sun is shining, but it will still not be particularly warm. With the upper-level ridging in western North America persisting, upper-level troughing will still be favored in eastern North America, cutting off any real surge of warmth from the south and west. Another low-pressure system tracking into southern Quebec on Saturday could lead to a brief warmup, especially in southern areas, but also clouds and rain, before another cool shot associated with a central Canadian high pressure system arrives for a couple of days. That cool shot is more likely to be accompanied by clearer skies, leading to surface daytime temperatures not being so cool, though that would also increase the chance of a hard freeze at night.
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| Source: TropicalTidbits |
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| Source: TropicalTidbits |
Warmth may become more dominant in late April, but confidence is not high
There are indications of the western North American upper-level ridging being replaced by upper-level troughing (-PNA) about a week from now, which would promote storms ejecting out of the Rockies, a downstream ridge over eastern North America, and more surges of warmth and possibly moisture into the eastern U.S., like for most of March. It remains to be seen how much of the warmth penetrates into eastern Canada, or if there's still enough cold air just to the north to create a stormy battle zone in our region, especially with the slightly negative NAO that could push the jet stream south, but it seems more likely that above-average temperatures will dominate in our region, which would really advance spring. It is still too early to have high confidence on this scenario though.
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| Source: TropicalTidbits |
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