Period of snow tonight and rain or snow Monday night; cold and dry Tuesday and Wednesday; then likely winter storms on Thursday and next Sunday and possibly more beyond with rather cold pattern

Plain-language summary:

 

After the coldest night of the winter so far and probably the entire winter for many, it will quickly warm up through tomorrow, even to above freezing for many areas south of the U.S./Canada border tomorrow. This will be accompanied by a burst of light to moderate snow, heaviest south of the U.S./Canada border tonight, as well as a period of snow in northern areas and rain changing to snow farther south tomorrow night. After turning much colder on Tuesday and Wednesday, a storm with snow possibly changing to ice and then rain at the end will occur on Thursday, with any changeover most likely in southern areas. Afterward, it will be cold and dry on Friday and Saturday before another storm, perhaps a widespread snowstorm, occurs on Sunday, though it is too early to be certain of this. While details of individual storms remain to be seen, the stormy pattern likely will continue beyond next weekend with plentiful cold still around.

 

Meteorological discussion:

 

Period of snow this evening, then period of snow or rain changing to snow Monday evening

 

Last night was the coldest night of the winter so far and probably for the entire winter for most areas, with widespread -10F (-23C) or lower along and northwest of the Appalachians away from urban areas and bodies of water, with some cold hollows even below -20F (-29C). The Arctic surface high pressure is moving off to the east, with southerly winds ramping up and some sunshine filtered through mid and high-level clouds warming it up quickly. A short burst of light to moderate snow is expected this evening, heaviest south of the U.S./Canada border this evening as a weak piece of energy enhances lift for a few hours. Behind that, southerly to southwesterly flow will advect much warmer air from the southwest, with many areas south of the U.S./Canada border reaching above freezing tomorrow with a little sun and little or no precipitation for most. However, another piece of energy moving eastward will bring another round of precipitation Monday evening. With the mild temperatures tomorrow, many areas south of a line from just south of Ottawa, Ontario to Bangor, Maine will start off as rain before evaporational cooling and some cold advection changes any rain over to at least wet snow before ending, though southern Vermont to far southern Maine may see all rain and only light rain. In northern areas, the rain and snow could be heavy at times despite the piece of energy being relatively weak, but that sometimes happens when there is forcing for lift aloft with relatively low stability and mild temperatures that can hold more moisture. With winds being temporarily weak during the disturbance, and temperatures being controlled more by latitude than elevation, precipitation and snow amounts will be latitude dependent and not be particularly elevation dependent, with the snow jackpot likely being around the Ontario/New York border eastward to central Maine.

 

Source: TropicalTidbits

Cold and dry Tuesday and Wednesday, then winter storms likely Thursday and Sunday

 

Arctic air mass returns for Tuesday and Wednesday, though it will not be as cold as last night. Meanwhile, a storm and upper-level trough ejecting out of the central Rockies, with a building ridge just off the Southeast U.S. coast, will lead to the storm tracking northeastward into the Great Lakes or Ohio Valley, with still some disagreement on the storm track and intensity. A stronger storm will push farther north and lead to a period of snow to change over to ice and then possibly rain right before precipitation ends, as the warmth first pushes in aloft but the low-level cold air taking longer to scour out. The changeover would be most likely south of a line from Ottawa to Montreal to Bangor, Maine. A weaker storm will stay farther south, leading to entirely frozen precipitation for most, and all snow from central New England on north. Colder air returns on Friday and Saturday before another storm likely takes aim at our region next Sunday. Initial indications are that this storm will track a little farther south than Thursday's storm, making it more likely for a widespread significant snowfall for our region, even in southern areas, though it is far from certain being still a week out. However, these storms going straight west to east from the U.S. West Coast to U.S. East Coast tend to be relatively easy to predict, with little or no phasing with other disturbances in another branch of the jet stream to complicate things too much.

 

Source: TropicalTidbits

 

Source: TropicalTidbits

Stormier and cold pattern likely to continue after next weekend

It seems like the increased storminess this week could be the start of the long-awaited stormier pattern. Ensembles indicate that upper-level troughing will generally prevail over the Rockies or move eastward into the Plains after next weekend, with the ridge just off the Southeast U.S. coast remaining prominent and helping to prevent storms coming out of the Rockies from being suppressed like in all of January. Storms taking this northeastward trajectory usually strengthen at least slightly, leading to good dynamics for ascent on the northern side, and also bring in Gulf of Mexico and western Atlantic moisture into the region. The upper-level ridging over Alaska ensures that there will continue to be an ample supply of cold air surging southward into the mid-latitudes, even farther south than next week as the AO turns negative, for the moisture to run into, favoring snow as precipitation type if the storm track is not too far north and west. A not-too-negative PNA (associated with an upper-level trough in western North America) would prevent storms from tracking too far northwest. If the trough moves eastward and deepens into the southern U.S., that would force a lot of cold air southward into the U.S. Plains, amplifying the pattern and potentially leading to Nor'easters that bring widespread heavy snow to New England. This pattern is why most models and CPC are showing a stormier and snowier February than average for our region. However, just how much snow anybody gets depends on the particular details of individual storms (e.g. track and intensity dictating the swath and intensity of snow from each storm) which won't be known until we get closer to each storm.

Source: TropicalTidbits

Source: TropicalTidbits