A storm around Thanksgiving will cause significant travel delays for tens of millions of people as it brings torrential rain to areas along the East Coast and the lower Ohio Valley, but snow will fly and accumulate farther north and west, AccuWeather meteorologists warn.

The storm dropped several feet of snow on California’s Sierra Nevada Range through Tuesday night and brought wintry conditions to Utah’s Wasatch Range and Colorado’s Rocky Mountains by midweek. Airline delays and cancellations at Denver International Airport can have far-reaching impacts across the country on a very busy travel day. While the storm delayed most long-distance travel in the East, it could scupper all travel and outdoor plans on Thanksgiving Day.

The rain will cause problems ranging from puddling and the risk of hydroplaning on the highways to poor visibility due to spray from other vehicles and areas of dense fog.

Low cloud cover and rain can also slow down air traffic. There will be more flight delays and cancellations as the storm hits major eastern hubs.

There is good news for the duration of the rain in the East: Most of it will be limited to a few hours in the Southeast from Wednesday night into Thursday as a cool front advances steadily, although gusty thunderstorms and torrential rain are possible.

Further north, rain will be limited to the first part of the morning around Washington, DC and should exit Philadelphia by the midday hours. Around New York City, rain will drench parade-goers in the morning, and it may take until the afternoon for the rain to completely clear the metropolitan area. Rain will continue throughout the day in the Boston area and possibly even into the evening.

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Further north and west, the bulk of the rain and snow will occur in the Ohio Valley states Wednesday evening and end by Thanksgiving morning.

“Where snow falls along portions of the Interstate 70 and 80 corridors in Illinois, Indiana and Ohio and continuing into part of western Pennsylvania, most of the snow on the roads will melt,” said Bernie Rayno, Chief On-Air AccuWeather meteorologist. “But where and when there is a steeper downhill slope, there can be some muddy and slippery areas.”

Further east, near I-80 and north of I-90, snow will increase in intensity and accumulate on colder, unpaved and elevated surfaces, as well as on some roads.

Slippery weather is expected in higher elevations from northern Pennsylvania and western, central and east-central New York State to central New England. In Northeast New York and northern New England, snow will accumulate on lower elevation roads and in the mountains.

The heaviest snow will fall in higher elevations from northeastern Pennsylvania and eastern New York to Vermont, New Hampshire, Maine and western Massachusetts, where 3 to 12 inches of snow may accumulate. The wide gradation of snowfall will be associated with increasing elevation. AccuWeather Local StormMax™ snowfall of 15 inches is most likely on the ridges.

The snow will be wet and sticky and will weigh down some trees and power lines, creating a risk of sporadic power outages. A power outage is never a good thing, but for many who prepare holiday meals, a power outage could really throw a wrench into their holiday plans.

As the storm moves northeast, January-like cold air will move across the Midwest later Thursday and Thursday evening and across the East Thursday night into Friday. In most cases, roads will dry out, but there may be some locations in the northern states and perhaps the southern Appalachians where moisture and slush will remain and become icy as temperatures drop.

As the cold air blows across the Great Lakes, it will bring severe weather, streaks of snow and heavy snow squalls that could create dangerous conditions for travelers after Thanksgiving. The lake effect may begin as early as Thursday over the Upper Midwest, but will significantly strengthen throughout the Great Lakes and interior Northeast Thursday night into Friday and may last through the weekend and early next week. The lake effect could have a much more serious impact on travel than the Thanksgiving storm over land, as it could strand motorists on highways.

As colder weather continues next week, storms from western Canada, known as Alberta Clippers, are expected to sweep across the Great Lakes and into the Northeast. These storms may carry light to moderate snow to the northeast coast.

Cold weather and snow of any kind evoke different emotions among a large group of winter sports fans. Ski enthusiasts will be pleased with next week’s pattern, which will capture much of the extended Thanksgiving holiday. Even where no fresh snow falls, many ski areas will be able to make snow and open slopes in the coming days due to the colder conditions.

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