Plain-language summary:
After last night's snowstorm south of the U.S./Canada border exits this afternoon, there will be a few snow showers along and northwest of the Appalachians this evening, but it will otherwise be dry through Tuesday morning. Some snow showers and perhaps even a few snow squalls along and northwest of the Appalachians are likely Tuesday evening. Then, a bigger storm on Thursday will likely bring heavy snow along and northwest of the St. Lawrence Valley, with at least a burst of snow to start to the south. Another storm with substantial snow for some is likely next Sunday. It will then turn cold again, and additional storms are possible, though it could also turn drier, and then eventually not as cold.
Meteorological discussion:
Snowstorm exits, snow showers this evening and Tuesday evening
A quick-hitting snowstorm south of the U.S./Canada border is quickly exiting this afternoon, leaving behind mostly dry conditions. However, a very weak low-pressure area centered in the Laurentians will bring a few snow showers this evening along and northwest of the Appalachians. It will then be a dry Monday and early Tuesday, though another weak disturbance tracking over southern Quebec will likely trigger a few snow showers or even snow squalls late Tuesday into Tuesday night, again mostly along and northwest of the Appalachians. It will turn very cold behind it as Arctic surface high pressure moves overhead the region, with many areas going below 0F (-18C).
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| Source: TropicalTidbits |
Major storms likely Thursday and next Sunday
There is an incredible amount of storminess in North America next week due to repeated storms hitting the U.S. West Coast and then traversing across the contiguous U.S. Meanwhile, upper-level ridging in Alaska and a negative AO will send arctic air into the mid-latitudes, with surface high pressure to the north of the storminess establishing and maintaining low-level cold air. This will occur even with a positive NAO, which will keep systems moving quickly and prevent any particularly meridional flow patterns. An elongated storm early in the week will pass to our south, but a stronger storm ejecting out of the Rockies will help build an upper-level ridge downstream in the western Atlantic, causing the storm to track much farther northwest. The storm will then move northeastward and collect moisture from the Gulf of Mexico, something that has not really happened this winter so far. Starting yesterday, models have consistently shown the surface low-pressure tracking up the St. Lawrence Valley, implying that the heaviest snow falls along and northwest of there, with areas to the south getting a burst of snow before getting dry slotted and possibly even changing to ice pellets, freezing rain, or rain briefly. This winter though, the trend has generally been for more suppression and weaker systems, so I wouldn't be surprised if it trends back southeast. Still, the details of the storm track and intensity remain to be ironed out, and that will determine who gets the heaviest snow and how much.
It turns colder behind the storm, but a moisture-laden disturbance coming in from the Pacific Ocean will reach the western U.S. on Friday and then track eastward across the contiguous U.S., reaching the U.S. East Coast by next Sunday. Given how much energy is involved with that, it is unlikely that our region will see nothing from it, but it is too early for any details, which would depend on the strength, location, and orientation of the disturbance as well as any interaction with the polar jet. It does appear that there will be enough cold air around for there to be a substantial snowstorm in at least parts of the area, though early indications are that it might favor southern areas. Mixed precipitation could also occur in southern areas if the storm is stronger and/or tracks farther north. It is remarkable how strong the signals have been for both storms next week for a few days already, given how far out the storms are.
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