National Weather Service United States Department of Commerce

Arctic Air Bringing Cold Temperatures to the Eastern Half of the U.S.; Strong Clipper System Wednesday and Thursday

Arctic air will continue below normal temperatures across the eastern half of the U.S. through today. A strengthening clipper storm will track north of the Great Lakes midweek with a widespread snow and gusty to strong winds through the region and into the Northeast U.S. followed by some lake effect snow. Read More >

A prolonged snow event brought heavy snow to many parts of eastern Washington and north Idaho during the weekend of 26-27 Jan 2008. While many locations of the Inland Northwest (such as the Cascades and Panhandle mountains) are used to heavy snowfall, this event was more than some residents were prepared for. More than a foot of snow fell over a large area including the populous Spokane/Coeur d'Alene metro area.

On Friday afternoon, forecasters continued to see the potential for a major winter storm event. A very moist low pressure system was nearly stationary off the west coast, bring heavy amounts of rain and mountain snow to California. Meanwhile a strong but somewhat dry cold front was moving down from the Gulf of Alaska. All indications pointed to a moist warm front from the California low moving northward and colliding with the cold front. The result would be a stationary front that would bring heavy snow to the north of the front and rain to the south on Saturday afternoon and evening. Eventually the cold air would push the front back to the southeast and into Montana.

 

IR Satellite Summary

 

The toughest part of the forecast was pinpointing exactly where this front would stall over the Inland Northwest. Computer forecasts showed various scenarios. Eventually the forecast was for the heaviest snow to fall south of Spokane over the Palouse and into the central Panhandle.

The satellite loop below shows the evolution of the event. The fronts did indeed collide as expected. However, the resulting stationary front set up a bit farther north than expected. This resulted in heavy snow over the Spokane/Coeur d'Alene metro area with mostly rain over the Palouse. By Saturday night the front had begun to slowly move to the southeast as expected.

 

IR Loop

 

A somewhat unexpected feature of this storm was the second surge of moisture from the California low early Sunday morning. This can be seen in the satellite loop above with a second area of enhanced clouds (pink and purple) moving into the area on Sunday. This surge pushed the front back to the north, redeveloping snow over the metro area, which persisted through the day. Eventually the front did move into the Palouse and southern Panhandle before exiting the region.

The image below show the radar mosaic for the event. The images are taken every three hours. You can easily see how stationary the front was on Saturday and Sunday, with nearly idential images for several hours. It's also easy to see how the precipitation started to move out of the area but was pushed back to the north on Sunday morning.

 

Radar Loop

 

A high resolution (every 30 minutes) loop of the radar imagery can be obtained if you click here. The file is very large (more than 6 Mb) and may take a long time to download.

Below is a loop of observed temperatures throughout the event. As you can see, warm air pushed into the southern Panhandle and the Palouse as temperatures warmed into the 30s and even lower 40s. Meanwhile cold air remained to the north and west.

 

Surface Temperatures

 

By Ron Miller