Northwest US braces for up to 15 inches of rain and a foot of snow in the mountains as 5,000-mile 'atmospheric river in the sky' stretching from China to British Columbia moves east

  • The Pacific Northwest was hit with heavy rains and strong wind on Wednesday
  • Meteorologists say the weather is caused by an enormous, 5,000-mile long atmospheric river that spans from China to North America 
  • Wind gusts of up to 45 miles per hour and 1.5 inches of rain were anticipated on Wednesday in Seattle 
  • The stormy weather is a prelude to what is expected to be an even wetter weekend in the region 
  • High-altitude locations could see between 10 and 15 inches of rain 
  • At least one foot of snow is expected to accumulate in Washington’s North Cascades mountains 

The Pacific Northwest was hit with heavy rains and strong wind on Wednesday thanks to an enormous, 5,000-mile long atmospheric river that spans from China to North America.

Wind gusts of up to 45 miles per hour were anticipated on Wednesday in Seattle where forecasters say up to 1.5 inches of rain could drop, according to The Seattle Times.

The stormy weather is a prelude to what is expected to be an even wetter weekend in the region.

High-altitude locations could see between 10 and 15 inches of rain while several inches of precipitation are expected in coastal areas as well as Seattle and Portland.

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The Pacific Northwest was hit with heavy rains and strong wind on Wednesday thanks to an enormous, 5,000-mile long atmospheric river (seen above) that spans from China to North America

The Pacific Northwest was hit with heavy rains and strong wind on Wednesday thanks to an enormous, 5,000-mile long atmospheric river (seen above) that spans from China to North America

Wind gusts of up to 45 miles per hour were anticipated on Wednesday in Seattle where forecasters say up to 1.5 inches of rain could drop

Wind gusts of up to 45 miles per hour were anticipated on Wednesday in Seattle where forecasters say up to 1.5 inches of rain could drop

The stormy weather is a prelude to what is expected to be an even wetter weekend in the region

The stormy weather is a prelude to what is expected to be an even wetter weekend in the region

A few feet of snow are being predicted for mountain peaks in Washington and Oregon.

At least one foot of snow is expected to accumulate in Washington’s North Cascades mountains.

Flooding is even possible in some parts of western Washington state, according to the National Weather Service.

‘Heavy #rain at times this week, could cause urban & street flooding! Be sure gutters & storm drains are clear of leaves & debris!’ the NWS tweeted on Wednesday.

Atmospheric rivers are long and narrow bands of water vapor that form over an ocean and flow through the sky.

They occur globally but are especially significant on the West Coast of the United States, where they create 30 percent to 50 percent of annual precipitation and are linked to water supply and problems such as flooding and mudslides, according to the National Oceanic and Atmospheric Administration.

A few feet of snow are being predicted for mountain peaks in Washington and Oregon

A few feet of snow are being predicted for mountain peaks in Washington and Oregon

Atmospheric rivers are long and narrow bands of water vapor that form over an ocean and flow through the sky

Atmospheric rivers are long and narrow bands of water vapor that form over an ocean and flow through the sky

Formed by winds associated with cyclones, atmospheric rivers typically range from 250 miles to 375 miles in width and move beneath the influencing effects of other weather.

The storm systems could bring welcome relief in the form of rain to Northern California, where wildfires have ravaged thousands of acres in wine country.

Some areas could see up to a quarter-inch of rain, which will help firefighters get the blazes under control. 

Most atmospheric river events are weak. 

But the powerful ones can transport an amount of water vapor equal to 15 times the average flow of water that flows out of the Mississippi River's mouth, according to NOAA's Earth System Research Laboratory. 

Meteorologists in the Seattle area are warning of possible floods this weekend. A stock image of the Seattle skyline is seen above

Meteorologists in the Seattle area are warning of possible floods this weekend. A stock image of the Seattle skyline is seen above

Last year, California saw record precipitation that ended a five-year drought thanks to an atmospheric river.

The improvement came despite the presence of the weather phenomenon known as La Nina, a cooling of waters in the central and eastern Pacific that is sometimes linked to unusually dry conditions. 

The lack of a La Nina influence and the disappearance of high pressure ridges over the West Coast that kept storms away in recent years has opened the door to atmospheric rivers.