The new forecast models are increasingly threatening for colder temperatures and lowland snow from Sunday through Wednesday of next week, although none of the forecast are ideal for a truly major event.  But you might consider getting prepared:  make sure you have chains and windshield decider for your car, be ready to protect sensitive plants– you know what I mean.  The TV stations should get all their colorful parkas cleaned and ready (no Jim Forman jokes…yet!).  And local DOT folk should stock and make sure their staff are well rested.

  On the left is the average of the ECMWF (European Center for Medium Range Forecasting) ensemble forecasts for upper levels (500hPa).   The average or mean of an ensemble or collection of forecasts tends to be more accurate than individual forecast model runs.  ECMWF has the world’s best global ensemble. The right is their single “deterministic” forecast.   Both show an upper trough offshore–a pattern very close to the typical western Washington snow configuration.   The U.S. model, which initially was much less threatening, has now come much closer to the ECMWF solution. 
  Our high-resolution regional models, forced by the NWS GFS model, indicates some snow (light) on Sunday, and a much more serious threat late Tuesday into Wednesday.  Lots of uncertainty, of course, at this range. Here are the 24-h snow predictions ending Monday at 4 PM and 4 AM on Wednesday.  Lowland snow in the forecast. 

The mountains are going to get it..no doubt about that…which is very good news for skiers.  Wax your skis!