Long Range Outlook: Winter Dry Spell Resumes For February

January 30, 2012

I just checked the long range maps again…and don’t see much of anything different from what I saw Friday. 

Amazing agreement on long range models showing strong ridging building over the Western USA and all the way up through Western Canada from this Thursday onward.  There MAY be some sort of change as we get past about a week from Saturday. 

But the screaming message is:

  1. Little to no rainfall is likely from this Wednesday afternoon through at least the 10th of February, possibly longer.
  2. Little or no snowfall in the Cascades for the next 10-14 days…essentially the first half of February could be snow-free in the mountains.    Just 3-5″ at best late tomorrow through Wednesday morning.
  3. No flooding, windstorms, snow to lower elevations…or strong wind for 95% of us during this period.
  4. Lots of chilly nights, sunny & comfortable days, and lots of fog at times in the Willamette Valley too during this period.  East wind developing Thursday in the Portland Metro area SHOULD keep the fog at bay for most of us Friday and beyond.
  5. The mountains and coast will be unusually warm this coming weekend.  60-65 is possible either day on the beaches and lots of 40s/50s at the ski areas.
  6. The other 5% that will get strong wind?  The west end of the Columbia River Gorge and east Portand Metro area will see gusty east wind beginning Thursday afternoon and it’ll continue for many days after that.

In this pattern strong high pressure sets up east of the Cascades and the Gorge wind machine will really get going.  For those that like to go experience the wind, this COULD be the strongest of the season so far due to several factors…one would be the orientation of the upper level ridge, slightly to our east or right overhead.  That’s always good for optimum placement of the surface high to our east.  The other is very warm 850mb temps Friday-Sunday, especially on the ECMWF.  It has temps up around +10 or slightly higher.  During the worst east wind episode I’ve seen since the late 1990s (January 2009), 850mb temps were up in the +15 to +18 degree range.  This causes the inversion to be quite low and strong, forcing all the air through a narrow vertical “channel” as well.   So this weekend might be “the big weekend” at Vista House.  Let’s aim for a 110 on the steps this time.  Plus, a mild sunny weekend in Portland always brings out the unsuspecting convertibles and sunglass wearing tourists…great fun.

So is winter over?  It could be, but that’s unlikely.  Remember last year?  You may recall that we had a month of dead weather from mid January to mid February.  Then a total pattern change with tons of mountain snow and our 2nd snowfall of the season around the 25th of February.  That is unusually late, but it can happen.  We never really recovered out of the cooler and wetter pattern until late July!

For the geeks, here are the 4 weekly ECMWF maps showing the forecast pattern over the next month:  2 weeks of strong ridging, then some sort of retrogression somewhere in the 2nd half of February.  Only 21 days away!  That was a joke for the regulars, of course we can’t predict too much 3 weeks ahead…

Chief Meteorologist Mark Nelsen