Special Weather Statement
There will be enhanced potential for ...

Pattern Change Coming, Western Cold Shot, Snow

By By Alex Sosnowski, Expert Senior Meteorologist
December 29, 2010, 1:28:48 AM EST

A major shift in the jet stream will drive cold air southward in the West as the year winds down and 2011 approaches.

A forecast dip in the jet stream will drive cold air southward into the West from midweek on. Just like a seesaw, warmer air will spring northward in the East.

The cold air had departed much of the West in advance of the monster California storm.

The coming new cold will fall short of the outbreak that occurred around and just before Thanksgiving. However, it will send temperatures 10 to 15 degrees below average over much of the West at its fullest extent.


The new air mass will set the stage for a chilly, if not cold, New Year for revelers in the West.

In addition, cold will spread into Southern California including, Pasadena, for the Rose Bowl Parade and game.

Western Weather Expert Ken Clark stated, "People camping out for good seats at the parade had better be prepared for nasty, freezing cold."

"The cold will fall a couple of degrees shy of the levels reached in late November over growing areas of the San Joaquin Valley, but will raise concerns for frost/freeze damage," Clark added.

The frost/freeze risk in California will follow the same in Florida by several days.

Along with the progressive cold from northwest to southeast in the West, snow will spread southeastward, and not just along the Rockies and upslope areas of the High Plains.


Significant snow is likely to reach well into the Four Corners region and will create problems for travelers through mountain passes from the Cascades to the Sierra Nevada and southern Rockies late in the week.

Clark said, "Salt Lake City, Boise, Spokane and Reno will get snow from this upcoming pattern change and the storm that it spawns."

Snow could also fall at fairly low elevations for a time in the coastal Northwest during the mid- to late-week period. "Some of the hills around Seattle may get a few snow showers," Clark added.

By New Year's Day, Eastern and Western parts of the nation will be nearly exact opposites as far as temperatures are concerned, compared to Christmas Day.

Meanwhile, a substantial storm will take shape at the junction of the cold air in the West and the building warmth forecast for the East, over the Great Plains.

The storm could evolve into a blizzard from parts of the central High Plains to the Upper Midwest over New Year's weekend.

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