Mainly Calm Weather Heading into December

November 26, 2017

9pm Sunday

Thanksgiving Weekend is wrapping up now with lots of you at home relaxing, getting ready to head back to work tomorrow.   I had some leftovers here at work…very nice.

Last week was quite warm, which cancelled out the cold first half of the month.  You can see the Pacific Northwest is running about average temp-wise so far this month.  The nation as a whole has been warmer than average:

Skiing has been shutdown on Mt. Hood now due to the washout through Thanksgiving Day.  Timberline just announced they won’t open again until Friday and Meadows/Skibowl are on hold as well, waiting for more snow this week.  The good news is that there IS some snow coming for the Cascades this week, 2-3″ fell this evening, and another 10-20″ is likely by next Sunday.  Here’s the ECMWF snowfall forecast:

Along with the 12-20″ (very dense & solid) base already on the ground that should allow some basic ski runs to open next weekend at both Timberline and Meadows.  Skibowl might be tougher since some of the snow falling this week won’t get below 5,000’…we’ll see.

In the lowlands it’s been a wet November once again but not crazy “flooding wet”.  In general it hasn’t been stormy this month like we sometimes see.

The rain this week should be relatively light.  I see one weak cold front coming through Tuesday, then another on Thursday afternoon/evening.  Other than leftover showers Friday and Saturday, that’s it for the next 7-10 days.   In fact the Friday/Saturday showers aren’t more than just showers because the main energy with that cold system dives south into California instead of heading into the Pacific Northwest.

If I don’t sound real enthused about the upcoming weather it’s because I’m not.  The pattern over the next 10+ days signals a very slow start to “meteorological winter” which begins on December 1st.    There DOES appear to be a change in the pattern about 8-10 days out.  A strong upper-level ridge builds right over us or just to the west, blocking storms and giving us mainly dry weather for NEXT week.  For now there is excellent agreement on this basic feature…look at the forecast GEM, & ECMWF ensemble averages of 500 millibar height 10 days from now…on Wednesday the 6th.


Then the GFS & ECMWF 5 days later…this is two weeks away…

They all look the same!  That’s some unusual model agreement that about 8 days from now the pattern will change.  It’ll feature an upper level ridge in the West (dry & mild) and cold troughing in the Eastern USA.  This is more likely a chilly east wind pattern for us, depending on the orientation of the upper-level ridge.   I will mention this in the 12 Day Trend…a graphic I use from time to time in the 2nd half of the 10pm show.


By the way, note this isn’t a 12 day FORECAST, but a general trend.  In fact I’d rather not have those “40s” on there or specific clouds for each day, so don’t read too much into that.  I like the text part best.

Regardless, it’s obvious the early part of December will not feature much active weather.  Weather Geeks:  Get your Christmas shopping and chores done now…who knows what is around the corner in mid/late December!  As I recall some seasons that started out slow suddenly saw the weather action pick up after early December (2008).  I think 2007 was pretty quiet too early on, followed by tons of foothill snow.

Chief Meteorologist Mark Nelsen