November 22, 2011 in City, Idaho

Wind, rain, mountain snow, heavy runoff expected

By The Spokesman-Review
 
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Turbulent, changing weather is bringing a mix of conditions across the Inland Northwest from high winds to heavy mountain snow.

Lower mountain slopes are vulnerable to small stream flooding as the change to a subtropical flow of air is threatening to unleash the snow pack below 3,500 feet in elevation. It is bringing temperatures in the middle to upper 40s across lower elevations today and Wednesday.

Snoqualmie Pass on Interstate 90 has been closed off and on throughout today, initially for avalanche control in the eastbound lanes, but later for all lanes.

With temperatures warming at middle elevations, lower-elevation passes should be negotiable in coming days.

At lower elevations, highways should be free of snow and ice during the Thanksgiving travel period. Periods of rain are expected in the Spokane and Coeur d’Alene areas through Thursday with drier conditions on Friday through Saturday night. More rain is in the forecast mainly for Sunday night.

Today’s high in Spokane reached the upper 40s as a warm front made its presence known east of the Cascades under a strong southwesterly flow off the Pacific Ocean.

Even more rain and high mountain snow are expected through Wednesday. Snow levels are rising above 5,000 feet.

Several school districts in Northeast Washington cancelled classes today because of treacherous driving conditions.

Spokane had about a third of an inch of rain overnight. Locations in mountain areas of Northeast Washington and North Idaho had higher amounts of precipitation. To the north, snow has changed to rain at lower elevations.

Tonight’s forecast calls for a tenth to a quarter inch of additional rain in Spokane. Accumulations will continue tonight and on Wednesday before the storm begins to ease on Wednesday night and Thanksgiving.

Winds in Spokane have been gusting to 33 mph at Spokane International Airport this afternoon.

A wind advisory remains in effect for the Spokane area, Coeur d’Alene, Columbia Basin and Palouse region through Wednesday morning.

An avalanche warning was posted for the eastern slopes of the Cascades north of Mission Ridge near Wenatchee.

The severe weather is being carried by a strong Pacific storm that reaches southwest into subtropical water, and is carrying a succession of waves of precipitation. The parent low over the northeast shore of the Gulf of Alaska is drawing up the mild air laden with moisture.

The mild flow should continue into the weekend, although the heavy precipitation will move to the west and leave the Inland Northwest under a drying trend on Thursday through Saturday.

The southwest flow splits apart late Saturday, causing the northern segment to push a cold front toward the region, ending the subtropical onslaught across the broader region.

Some parts of the Cascades could see up to 3 additional inches of precipitation. Mountains in the Inland Northwest could see 1 to 1.5 inches over the coming day and a half.

Forecasters said the snow pack should absorb the rain at elevations from 3,500 and higher, meaning ski areas are not likely to lose their base snowpacks, an important component to keeping open this time of year.


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