The National Weather Service has updated its seven-day forecast to include Thanksgiving Day. And while the chances of rain and snow are low for most of the country (save for parts of the Southeast and mid-Atlantic) next Thursday, some chilly temperatures are expected, especially in the northern Plains.

Days after a bomb cyclone took aim at the Pacific Northwest, killing two people and leaving behind widespread damage, an atmospheric river linked to that system continues to dump record-breaking rainfall on Northern California.

Some California locations have seen more than 20 inches of rain over the past three days, UCLA climate scientist Daniel Swain said in a press briefing Friday, noting that those totals were “exceptional and record-breaking.”

“This storm is not over yet,” Swain added. “In fact, it is set to peak in certain places.”

The atmospheric river began drifting south Friday, bringing heavy rain to San Francisco. Downpours continued in Marin, Sonoma and Napa counties, where double-digit rainfall totals have already been observed.

The National Weather Service has issued flood warnings and watches throughout the northern portion of the state and more rain is expected over the next week.

The twin weather systems impacting the Pacific Northwest and the Northeast have left hundreds of thousands of people without power. According to PowerOutage.us, more than 100,000 customers were without power in northeast Pennsylvania and more than 36,000 in central New York early Friday afternoon as heavy snow knocked down trees and power lines.

In the Pacific Northwest, nearly 200,000 customers remain without power in Washington state in the wake of this week's bomb cyclone. In California, the number climbed to over 36,000.

States with the most power outages (as of 1:30 p.m. ET):

• Washington: 188,292

• Pennsylvania: 127,166

• New York: 36,689

• California: 15,502

Source: PowerOutage.us

While heavy rain and snow are impacting millions of people in the Northeast today, conditions are expected to simprove by later this weekend, according to the National Weather Service:

A winter storm warning remains in effect today for portions of northeast Pennsylvania and central New York, where up to a foot of snow or more is possible in the higher elevations.

The National Weather Service in Binghamton, N.Y., said snow fell one-to-two inches fell per hour across western portions of the Catskills overnight, warning that "heavy snowfall could bring down trees and wires due to the weight of the snow."

"Totals will be highly elevation dependent," it added. "Accumulations of 1-4 inches in valley locations with totals of 6-12 inches above 1,500 feet. Totals of 12 to 16 inches in the highest elevations."

The atmospheric river thats wreaked havoc in the Pacific Northwest this week will "produce one last round of heavy rain/mountain snow and strong wind gusts" across the region Friday, the National Weather Service says.

According to its latest short-range forecast, three to five inches of additional rain is expected across portions of Northern California, with up to 10 inches of rain possible for the northern Sierra Nevada region.

In addition:

Heavy mountain snow is expected over the Washington Cascades and Northern Rockies through Saturday. Multiple feet of snow are likely to accumulate over portions of the northern Sierra (above 7000') by Saturday evening. Strong winds will continue across coastal areas of northwest California into western Washington, and over south-central Oregon. These winds may blow down trees and power lines, and additional power outages are possible.

Temperatures for much of the U.S. will be below normal temperatures for this time of year from Nov. 29 through Dec. 5, according to the National Weather Service.

American Airlines is calling out passengers who try to budge in the boarding line. How would it work?

If a customer boards before their assigned boarding group and their ticket is scanned, the new software won't accept their boarding pass. It will also make an audible sound to alert the gate agent and customer that their group hasn't been called yet.

The technology is expanding to more than 100 airports across the U.S., just in time for the busy Thanksgiving holiday travel season.

Read more from WJZY: American Airlines adding new technology that calls out boarding line rule-breakers

Photos show the effects of heavy rains and wind due to a strong and lingering atmospheric river affecting Northern California.

Coastal areas of northwest California are expected to see "dangerous flooding" because of the ongoing atmospheric river conditions, according to the National Weather Service.

Venado, Calif., has seen 12.68 inches of rain, while 16.2 inches of snow have been reported in Mazama, Ore., meteorologists said.

Below are other snow, rain and wind totals resulting from the atmospheric river conditions in the region.

Weather could disrupt travel on the Tuesday and Wednesday before Thanksgiving, which are some of the busier travel days of the holiday week.

"One storm over the eastern half of the country is forecast to spread rain and snow showers across the Great Lakes, while periods of rain dampen areas from the Ohio Valley southward into Arkansas and Tennessee," AccuWeather meteorologist Brian Lada said in an online forecast.

"Rain could then advance toward the major Northeast cities along the Interstate 95 corridor Wednesday."

Meanwhile, the weekend storm affecting the West Coast will push inland, bringing rain and snow in the mountains, including the Sierra and Rocky mountains.

Weather troubles may complicate an already busy Thanksgiving holiday travel week ahead, when an estimated 80 million Americans are expected to travel, according to AAA.

For those looking to get a head start on travel over the weekend, much of the U.S. will be dry, except for the West Coast and Northeast. From California to the Pacific Northwest, rain and mountain snow will extend eastward into the Rockies, according to Weather.com.

In the Northeast, travelers could see portions of rain and higher-elevation snow, which could affect air travel due to strong winds, so be prepared for some delays, USA Today reported.

More than 23 million people are under winter weather advisories, most of whom are in the eastern U.S. and Great Lakes region. This includes parts of New York, Pennsylvania, West Virginia, western Virginia, western North Carolina, Kentucky, Indiana, Ohio and Wisconsin.

Northern Pennsylvania and southern New York could see at least 6 inches of snow, while the mountains of West Virginia, Maryland and southwest Pennsylvania could see up to a foot of snow.

Eastern Wisconsin could see between 3 and 4 inches of snow, with wind gusts up to 40 mph, according to the National Weather Service.

Light snow could reach as far south as North Carolina.

Meanwhile, parts of the Northwest in Washington, Idaho and Montana are also under advisories where heavy snow is forecast through Sunday, according to the weather service.