First taste of winter for Northeast with major storm system
Monday, December 4, 2017, 13:56 - December 1st marked the first day of meteorological winter, and while autumn has been deficient when it comes to snow and cold for most of the country, this new month looks to make up for lost time.
A big pattern change is on the way from coast to coast. As the Pacific Northwest gets a break from the relentless unsettled weather of the past month, the action finally spills over the Rockies, spawning a low pressure system that will bring rain, snow, and the potential for severe weather to much of the eastern half of the country in the week ahead. Read on as we break down what to expect.
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The first weekend of December saw above-average highs for most of the country east of the Mississippi, but those temperatures are about to come tumbling down. A powerful low pressure system developing Sunday night over the northern Plains will send a plume of moisture into the western Great Lakes by Monday morning, marking the start of a string of stormy days for the Upper Midwest and Great Lakes region.
Rain, along with a strong final push of warm air, move into the Upper Midwest through the pre-dawn hours on Monday, with heavy rain and even a few thunderstorms expected into the western Great Lakes by Monday morning. This surge of warm air will be short-lived, however, as the potent system pushes east. The cold front following quickly behind brings the risk of snow through the northern High Plains starting by dawn on Monday morning, along with the risk of a mixed area of sleet or freezing rain. Rain changes to snow as the system moves east through the day; Fargo should be into the frozen precipitation late Monday morning, with snow moving into Minneapolis through the evening hours.
Click play to watch below: Storm track and timing
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The strong winds that brought the surge of warm air ahead of the system turn against the region, too, bringing cold gusts from the north and ramping up the wind chill. Blizzard conditions are possible over parts of the Upper Midwest, especially closer to the Canadian border in Minnesota. These strong winds from the north and northwest will continue whipping up the freshly-fallen snow through Tuesday night.
Click play to watch below: Snowfall forecast
The system continues its march east on Tuesday, as the main area of low pressure pulls north toward Hudson Bay and the cold front drapes the country from the Great Lakes to the Gulf of Mexico. Areas of snow will linger across parts of the Upper Midwest and western Great Lakes, as winds become favorable for lake-effect snow - something that will become a fixture of most of next week across the region.
Further east, rain will mark the front's passage. A band of heavy rain and showers associated with the cold front pushes through western Pennsylvania and the Ohio Valley Tuesday morning, reaching New England and the Mid-Atlantic by Tuesday evening. A few rumbles of thunder are possible throughout the day ahead of and along the front, though these storms will most likely be non-severe in nature.
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The bulk of the system is expected to have push offshore by Wednesday afternoon, with showers lingering through the morning for eastern New England, parts of the Atlantic coast, and northern Florida. Behind that, Wednesday will be dry away from the Great Lakes, but this drying out will be accompanied by diving temperatures as cold air surges down from the north.
The lake-effect snow machine will be firing up courtesy of these cold winds from the northwest, and models suggest that flow off the lakes will be in place at least through next weekend. This will lead to some significant snow accumulations for parts of Michigan, Pennsylvania, and Upstate New York through the rest of the week.
Watch below: Lake-effect snow forecast
This week's pattern change will set the pace for the month ahead, according to longer-range guidance. A more amplified jet stream pattern - with a strong ridge in the west and a deep trough in the east - suggests that cold air will be in place for at least the next few weeks across the east.
Thumbnail courtesy: David Wilson from Oak Park, Illinois, USA [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
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