Multiple weather threats will be deployed across the eastern half of the U.S. from Friday through Monday. Credit: CNN Weather

(CNN) -- A powerful storm will affect much of the eastern half of the U.S. this weekend with torrential rains, heavy storms, hurricane-force winds and even snow.

The weekend storm will begin to take shape on Friday as an area of low pressure develops in the southern Plains. Leftover energy from a deadly atmospheric river in the Northwest earlier this week will reach the central U.S. and increase the strength of the developing storm.

  • One person dead after the powerful atmospheric river that fell on the northwest of the US with more than 200 mm of rain

The storm's impact will linger until late Friday, when it becomes more organized and moves from the southern Plains into the Midwest.

From there, the storm's impact will increase substantially, with heavy rain, thunderstorms, and gusty winds reaching across the East over the weekend.

Saturday: Severe Storms

As the storm strengthens and expands its reach on Saturday, severe weather will stretch more than 1,930 kilometers from the Gulf Coast to the Canadian border.

Chance of severe thunderstorms in portions of the South on Saturday.
Credit: CNN Weather

Thunderstorms will rumble Friday night with a small window in which isolated severe storms could develop across parts of Oklahoma, Arkansas and Texas, ahead of Saturday's threat to the south.


The main thunderstorm event will get underway across portions of the south Saturday morning as a cold front associated with the short easterly storm across the region. Some of these storms could become severe and bring gusty winds and hail. A slight risk, or level 2 of 5, of severe storms is forecast in parts of Texas, Louisiana, Arkansas and Mississippi, especially Saturday afternoon.

As the odds of damaging thunderstorms increase Saturday afternoon, the storm will also spread rain across a wide portion of the country, from the Gulf Coast to the Midwest. Rain will begin in the early hours of Saturday in parts of the Midwest and Mississippi Valley and spread eastward throughout the day.

Rain will be steady as the day progresses and could become heavy at times, especially in the south.

Fortunately, the storm is likely to move at a rapid pace that will prevent precipitation totals from skyrocketing, but any soggy rain could cause flooding problems.

Strong winds will also accompany any precipitation, even outside of thunderstorms.

A thin swath of snow accumulation is possible Saturday from Wisconsin to Michigan's Upper Peninsula, but this will be mostly a rain event for much of the Midwest.

Sunday: Strong Wind

The storm will reach its maximum strength in the afternoon as it expands and engulfs much of the East. The storm's wind gusts will be significantly stronger on Sunday compared to Saturday and could knock out power and disrupt travel.

Widespread gusts of between 65 and 80 km/h will hit the Mid-Atlantic and Northeast. Gusts will be even higher, reaching 96 km/h Sunday night in New England and coastal areas of New York and New Jersey.

Predicted wind gusts are shown Sunday night in the East. Credit: CNN Weather

Such strong winds, especially when combined with rain, could topple some trees and cause power outages. High winds and rain can also disrupt air travel through the corridor and lead to slowdowns for drivers.

Outdoor Christmas decorations that are not secured can be blown away by the strongest winds.

Rain will be the main type of precipitation from Florida to New England, with widespread amounts of 25 to 50 mm. Higher totals are possible for areas drenched by multiple rounds of downpours.

Some thunderstorms will make their way into the rain zone, including in the North. A few storms may become severe on Sunday, with an area from Georgia to Virginia most likely to endure a handful of damaging storms.

Rain may change to wet snow across higher elevations in West Virginia, Pennsylvania and New York on Sunday night as cold air pushes eastward in the tail of the storm.

Predicted snow accumulation for two different weather models is shown. Taken together, these two forecasts provide a good idea of how much snow could fall this weekend. Swipe to see each forecast.

Portions of New England could change to a wintry mix of rain, snow and freezing rain late Sunday night and continue for a while Monday.

The exact times of change and amounts of snow will depend on how quickly cold air can enter the region.

Monday: Cold envelops the east

The storm will begin to move away from the East Coast on Monday, but rain and snow will continue across much of New England and parts of upstate New York through the afternoon before tapering off in the evening. Rainy and windy weather will come to an end in New York City on Monday afternoon, while gusty winds will slowly subside in the rest of the Northeast except New England.

Monday will be much colder across the eastern half of the country as a result of the storm. The temperature difference between Monday and the weekend above the average December temperatures will be most marked from the southeast to the northeast.

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