Plain-language summary:
It is a quiet, seasonably cold, and mostly sunny weekend weather-wise as a moisture-rich storm misses to our south again. It will then turn milder through Tuesday with very minor snows late tonight and Monday night. It then turns colder late Wednesday through the weekend with storminess possible starting Friday but the overall weather setup is slow-moving, messy, and uncertain. It then turns cold and dry for a few days before potential thawing and storminess for the last week of February.
Meteorological discussion:
Mostly sunny this weekend, then milder through Tuesday with very minor snows
It is a quiet and mostly sunny weekend weather-wise as a moisture-rich southern jet disturbance to the south will be pushed out to sea by an unfavorable suppressive zonal jet stream configuration, making for a missed opportunity for a big snowstorm that some models showed a week ago, typical of recent winters. It will be seasonably cold or somewhat colder than average, especially at lower elevations which are actually colder than higher elevations due to the clear skies, widespread snow and ice cover, and surface high-pressure overhead that while is not arctic in nature, is sort of generating its own low-level cold with weak wind underneath the inversion aloft.
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| Source: TropicalTidbits |
A weak, stretched-out piece of energy extending north of the main storm will bring a little snow to the Adirondacks and maybe eastern Ontario and southwestern Quebec tonight, but accumulations for most will be minimal. However, the persistently cold weather pattern is changing, with a -PNA and associated western North American trough, not seen much this winter, promoting an upper-level ridge in the central U.S. Meanwhile, not far behind, an elongated clipper whose center will pass over northern Quebec will bring light precipitation all the way down to the Adirondacks and northern New England Monday evening, likely as snow for most, though the low-levels are warm enough for a bit of rain or freezing rain in the downslope-warmed areas of the southwestern St. Lawrence Valley and far northwestern Adirondacks. Accumulations will be light for almost everyone regardless. Given the clipper's track and southerly winds, the heaviest snow will likely occur in the Laurentians. After that, with some clearing of clouds and the stronger February sun, Tuesday will be the warmest day in a month or more, with many lower elevation locations reaching or exceeding 40F (4C).
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| Source: Climate Prediction Center |
Turns colder later Wednesday through rest of week, with moisture-rich storm suppressed to the south again
However, an arctic surface high-pressure will nose into Quebec behind the clipper on Wednesday, leading to low-level cold air from the north to enter our region, ending the brief thaw and squashing the real warm air to the south. The associated upper-level trough will dive into Atlantic Canada, and the northwesterly flow aloft in our region will again suppress the first storm ejecting out of the Rockies resulting from the -PNA pattern to the south of our region. It is amazing how good this Atlantic Canada trough is at suppressing rich Gulf of Mexico moisture this year! This is yet another missed opportunity at a bigger storm in our region, perhaps except southern Vermont to far southern Maine. It is also a bit surprising this time given that the high-latitude blocking is weakening (NAO actually turning positive) and models showed a potential thaw several days ago, but this winter just has not favored big, moist storms to come from the southwest, with Atlantic Canada upper-level troughs seemingly always cutting off the otherwise moist southwesterly flow. The suppressive flow will not only push the precipitation south of our region, but also make the area of precipitation very narrow, with snow only on the northern edge of it.
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| Source: TropicalTidbits |
Uncertain and messy weather pattern Thursday through following Monday with multiple chances of storminess, though unlikely to get any one big storm
Beyond Thursday, the weather becomes increasingly uncertain and messy as multiple disturbances eject out of the broad, slow-moving upper-level trough in the western U.S. through next weekend. The disturbances will track along a battlezone between the warm, moist Gulf of Mexico air to the south and arctic air to the north that is trying to squeeze the warmth and moisture southward. It is also not clear how slowly the Atlantic Canada upper-level trough will move; some models show it getting reinforced and getting cut-off from the main polar jet to the north, causing it to meander around there until next weekend, which would leave our region dry, especially northern areas, as the confluence and west-northwest flow aloft suppresses all the disturbances to the south and weakens them, an amazing outcome given all the storminess entering the western U.S. However, other models are showing it moving out faster and too far east to affect our weather by later Friday, which would allow a second storm to move in and produce snow and possibly mixed precipitation in southern areas by Saturday. There might even be a third storm for the following Monday, but how all these pieces interact is a big question mark, and I wonder if there could be too many disturbances for any one of them to be a major storm, a frequent occurrence in recent winters. It also appears to be a rather slow-moving weather pattern with the upper-level troughs almost becoming cut-off, making the weather especially difficult to predict.
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Source: TropicalTidbits |
Cold and dry for middle of following week, then possible thaws and resumption of storminess
After the series of disturbances, it will likely turn cold and dry again for a few days as a surface high-pressure likely coming out of the arctic settles in as the upper-level ridge briefly returns to the western U.S. However, beyond that, another upper-level trough is likely to enter western North America, perhaps farther north than the one this upcoming week. Many models are showing this to promote a storm to track farther north from the central Rockies to north of our region, leading to a thaw and rain. However, they also showed this at times for this upcoming week, and I am a little skeptical for now. All it takes is one well-timed disturbance to bring arctic air just ahead of the Rockies storm, and it would thwart the thaw and lead to snow instead. Long-range signals point to a southern U.S. ridge and some upper-level troughing in western Canada appear to be favored, a bit different from most of this winter but more typical of a La Niña winter. While not the ideal setup for big snow and storminess and especially the (now rare) Nor'easters, it is perhaps a less blocked weather pattern with more ups and downs in temperatures and regular storms criss-crossing the U.S. and southern Canada without necessarily being suppressed to our south as much. That also opens the possibility of thaws if the storms are stronger and track farther north. However, western Canada appears very cold, and some of that is likely to reach our region. Ideally for big snows in our region, we would want upper-level troughs digging just to our west or southwest with an upper-level ridge over Atlantic Canada to prevent suppression and allowing the storms to intensify as they approach our region, but that appears to be very rare in recent winters.
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| Source: TropicalTidbits |
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