Northeastern US storm to deliver rain, wind, snow and usher in much colder air

A strengthening late-week storm will unleash flooding rain, wind and a wintry mix as it ushers in much colder air to the northeastern U.S., acting to trigger the first episode of lake-effect snowfall for some areas to the lee of the Great Lakes.

Two separate systems will combine to produce this multi-faceted and winterlike storm, including one storm that will first spread snow across the Midwest and another that will form along the mid-Atlantic coast.

Rain and wind to cause flooding and bring down autumn color

Wet weather will begin to infiltrate the Northeast early on Friday, including across Ohio, the Virginias and Maryland. By the middle of the day, rain will be falling across much of New York and Pennsylvania.

Early in the day, the heaviest rain will likely be confined to the Appalachians. However, heavier rain will shift into Maryland, eastern Pennsylvania and the Hudson Valley by the afternoon and evening hours.

"The timing of the steadier, heavier rain in the I-95 corridor, from D.C. to New York City, means that the evening commute could be troublesome," said AccuWeather Meteorologist Steve Travis.

At times, downpours could reduce visibility for motorists and create ponding on the roadways.

Through the evening, rain will continue to advance north and east into New England. This could make for wet high school football games or even the cancellation of some high school sporting events.

Download the free AccuWeather app to check how much rain is expected for your area and also to check MinuteCast® to see when rain will be arriving.

Rainfall amounts through Friday night will generally surpass 0.50 of an inch of rain but could reach as high as 1.50 inches where the heaviest rain falls.

Low-lying and poor drainage areas will be most likely to get any flooding. However, the falling leaves this time of year could expand flooding and travel issues.

"Heavier rain and any breezy winds could increase the number of leaves falling off the trees. In addition to the leaves that have already fallen, these could clog storm drains, leading to urban flooding issues," Travis added.

Wet leaves also create a more slippery surface on roads and sidewalks, which can prompt the need for more cautious driving tactics.

Snow to mix with rain in New England

Noticeably cooler air will be present across much of the Northeast ahead of this storm; however, the air will still fall short of the freezing mark, removing the chance of widespread snow across the region.

Northerly locations will still have the chance for snowflakes to mix in, especially as temperatures fall on Friday night.

"Other than at the onset of the storm, where the Laurels of Pennsylvania and in the Alleghany Plateau New York could get some snow, the majority of the snow with this storm will fall on the western flank," Travis said.

By Friday evening, most of the rain will be done across western New York and northern Pennsylvania, but that's when there could be a change to snow.

"Although a lot of accumulation is not expected, there can be an inch or two of accumulation, especially on grassy surfaces," Travis added.

Higher snowfall accumulations will be confined to the higher elevations or any spot located under a lake-effect snowband into Saturday night.

December-like air to grip the Northeast for the weekend

Progressively colder air will pour into the region Friday into the weekend.

"After being in the 50s in Philadelphia on Friday, temperatures will drop to the middle 40s during the weekend," said AccuWeather Senior Meteorologist Mike Doll.

Similar temperature falls will occur in D.C. and New York City.

Meanwhile, high temperatures will be mainly confined to the 30s in cities like Pittsburgh; Buffalo, New York; and Burlington, Vermont.

Communities from the Appalachians on west will end up being as much as 20 degrees below normal.

Brisk winds on Saturday will make it feel even more wintry. With gusts up to 35 mph at times, AccuWeather RealFeel® temperatures will drop into the teens and 20s.

This will be one of several waves of cold air over the next week that will expand from the core of cold gripping the northern Plains.

Lake-effect snow downwind of the Great Lakes

The cold pushing over the Great Lakes Friday and through the start of the weekend will create prime conditions for lake-effect snow.

"As cold air rushes over the Great Lakes, some lake-effect snowbands will really fire up," said Travis.

Areas particularly at risk will be the Tug Hill Plateau east of Lake Ontario and in ski country of western New York.

"While the higher elevations will get the most snow, some people living in the valleys could see snow this time as well," Travis added.

Snowfall accumulations will be high enough to require plows and shovels for those downwind of the lakes.

Any heavier snow squall can drop visibility very quickly, leading to difficult driving conditions.

While the lake-effect snow is expected to shut off on Saturday night, this will likely be the first of several events in the next week or two.

"The long-range weather pattern continues to show waves of cold across the Great Lakes," said Doll.

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