Real Winter temperatures on the way

The Pacific NW will be having winter temperatures this coming weekend (12/12/08-12/14/08) and into next week.  This cold airmass had been seen in the forecasting models for at least a week - and it still looks like the models are holding up.  The snow possibilities are looking iffy - getting the moisture and the cold at the same time here is always difficult.  Usually though, cold comes in with a dry airmass.  Getting a storm like the 1991 Halloween Blizzard is not very likely around here.

We'll see what happens.  Sunday looks like the best chance of snow down in the Willamette Valley.  That's when the cold and moisture have the best chance of meeting up for a dance.

Cold forecast from The Oregonian website

SPECIAL WEATHER STATEMENT

NATIONAL WEATHER SERVICE PORTLAND OR

443 AM PST THU DEC 11 2008

ORZ005>009-014-WAZ023-039-112300- LOWER COLUMBIA-GREATER PORTLAND METRO AREA- CENTRAL WILLAMETTE VALLEY-SOUTH WILLAMETTE VALLEY- WESTERN COLUMBIA RIVER GORGE-UPPER HOOD RIVER VALLEY- GREATER VANCOUVER AREA- INCLUDING THE CITIES OF...ST. HELENS...CLATSKANIE...HILLSBORO..PORTLAND...OREGON CITY...GRESHAM...SALEM...MCMINNVILLE...DALLAS..EUGENE...CORVALLIS...ALBANY...HOOD RIVER...CASCADE LOCKS..MULTNOMAH FALLS...PARKDALE...ODELL...STEVENSON...SKAMANIA..VANCOUVER...BATTLE GROUND...WASHOUGAL 443 AM PST THU DEC 11 2008

A STRONG COLD FRONT EXPECTED TO MOVE THROUGH FRIDAY AFTERNOON WILL USHER IN THE COLDEST AIR MASS SO FAR THIS SEASON...THEN A SECOND COLD FRONT...WITH ARCTIC ORIGINS...IS EXPECTED TO SPREAD EVEN COLDER AIR IN FROM THE NORTH SUNDAY AND SUNDAY NIGHT.

LOW TEMPERATURES IN THE WILLAMETTE VALLEY WILL FALL TO 15 TO 20 BY SUNDAY AND MONDAY NIGHTS...WITH HIGHS NEAR FREEZING SUNDAY THROUGH TUESDAY. EVEN COLDER TEMPERATURES ARE POSSIBLE IN THE UPPER HOOD RIVER VALLEY AND COLUMBIA RIVER GORGE...WITH LOWS AS LOW AS 10 TO 25. ..AND DAYTIME HIGHS JUST 15 TO 25.

THE COLD AIR MASS WILL ALSO BRING A CHANCE FOR LOW ELEVATION SNOW SHOWERS. FRIDAY NIGHT THROUGH SATURDAY NIGHT THE FLOW WILL REMAIN ONSHORE. THIS WILL KEEP THE LOWEST ELEVATIONS ON THE VALLEY FLOOR AND THE MAIN CITY CENTERS FROM GETTING ANY SNOW ACCUMULATION. SNOW WILL MIX WITH THE RAIN AT TIMES AND COULD BRIEFLY CHANGE TO ALL SNOW BUT NO ACCUMULATIONS IS EXPECTED. HOWEVER IN AREAS ABOVE 700 TO 800 FEET THE PRECIPITATION WILL BE MAINLY IN THE FORM OF SNOW. SEVERAL INCHES OF SNOW ACCUMULATION IS LIKELY IN THESE AREAS ABOVE 700 FEET THROUGH SATURDAY NIGHT.

ON SUNDAY ANOTHER STORM AHEAD OF THE ARCTIC FRONT WILL DROP SOUTH ALONG THE COAST. THE STRENGTH AND MOISTURE AVAILABILITY IS STILL UNCERTAIN AT THIS TIME. HOWEVER IF THIS TRACK HOLDS THERE WILL BE A VERY GOOD THREAT OF STICKING SNOW TO THE VALLEY FLOORS. THE SNOW THREAT WILL CONTINUE INTO SUNDAY EVENING BEFORE THE SNOW TURNS TO FLURRIES OVERNIGHT.