Plain-language summary:
After a lack of thaws since the beginning of January, it will be rather mild from Monday through Wednesday or Thursday, with light rain and snow showers, with mainly rain expected south of the U.S./Canada border but snow more likely to the north and over very high elevations. A period of heavier snow will occur in the Laurentians Monday evening, and somewhat heavier precipitation is possible region-wide on Thursday. It will then turn much colder on Friday with likely snow showers, before a clipper brings light snow to our region next weekend, and then it turns much colder for a few days afterward. A big storm is possible around March 4, perhaps with mixed precipitation, before turning much colder again but possibly drier afterward.
Meteorological discussion:
Thaw starting with little or no precipitation outside snow in Laurentians Monday evening
This winter, especially since the beginning of January, has been marked by a lack of thaws that is unusual in recent winters, allowing the snowpack to build up, especially in February which has been the snowiest month of the winter for most. However, the snows have mostly shut off this week with drier but still cold weather, and now, a mild spell will be upon us for at least the first part of the upcoming week. Although the +PNA is allowing deep westerly to west-northwesterly flow, preventing warm moist air from the Gulf of Mexico from entering our region, the +NAO and +AO promoting repeated surface low-pressure systems to pass to the north is allowing low-level westerly and southwesterly flow that is dominated by Pacific air downsloped off the Rockies, cutting off any arctic air. This is a mostly dry flow as well, limiting any precipitation, though one disturbance with westerly low-level flow is producing light upslope snow showers in the Adirondacks, Green Mountains, and Eastern Townships of Quebec today while it is still cold enough for snow, while another stronger low-pressure system moving into James Bay tomorrow evening will produce southerly to southwesterly low-level flow with upslope snow in the Laurentians while it rises above freezing with little precipitation elsewhere.
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| Source: TropicalTidbits |
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| Source: Climate Prediction Center |
Mild Tuesday through Thursday with some rain and snow showers, then turning much colder on Friday with snow showers, clipper produces light to moderate snow next weekend
After the low-pressure pushes to the northeast of our region on Tuesday, we will be left with mild Pacific air with periods of sun and clouds. The higher late February sun angle will lead to temperatures rising well above freezing, likely in the 40s F (5-9C) in many areas, especially south of the U.S./Canada border, with the deep snowpack and some clouds perhaps inhibiting even warmer temperatures. Some rain showers are possible Tuesday night as a very weak disturbance rolls through, with temperatures too warm for snow at lower elevations, and there will likely not be much precipitation anyway given how weak the dynamics are. The disturbance will bring slightly cooler air on Wednesday ahead of another weak but slightly stronger low-pressure system aimed right at our region on Thursday. Temperatures look very marginal with perhaps a brief period of snow changing to light rain in southern areas with snow more dominant north of the U.S./Canada border, northern Maine, and at very high elevations. Another weak disturbance could bring widespread snow showers along and northwest of the Appalachians on Friday before a very cold Arctic air mass comes in directly from the north with no modification before quickly turning milder south of the U.S./Canada border over the weekend as a clipper moves into or possibly even north of our region, bringing light to possibly moderate snows to many especially in higher terrain, eastern Ontario, southern Quebec, and northern Maine.
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| Source: TropicalTidbits |
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