rain

7pm Sunday…

Today was spectacular wasn’t it?  Other than some spots of morning fog, wall-to-wall sunshine for the entire region.  I just caught the sun setting from our Shilo Inns Seaside camera out at the coast

Cam Seaside

Portland made it above 70 degrees today, the first time we’ve reached “normal” in 11 days!  It was quite a cool end to September and early October too.  I suppose that’s perfectly reasonable after months (years) of above average temps.  The warm temps were courtesy of a warmer atmosphere overhead plus a good amount of morning easterly wind.  Vista House gusted to 42 this morning; a small preview of the upcoming 5 months.

Tomorrow will be dry west of the Cascades from Longview to Eugene, at least up until around 5pm.  At some point after that (depending on location) the chance for showers picks up and your home may even get an hour or two of steady rain between 5-11pm Monday evening.  The rain will be along a strong cold front.  Freezing levels start at 11,000′ tomorrow at 5pm and within 12 hours plummet to 4,000′!  It’s another sharp upper-level trough dropping out of Alaska, headed for Washington and Idaho.  This one appears to be slightly colder than the one a week ago, for our area.  Not as cold for the northern Rockies.  But we’re also 8-10 days deeper into the autumn season; the same airmass overhead should be a bit cooler in the lowlands.   So even with partial clearing Tuesday afternoon plus a mainly sunny Wednesday, it’ll be tough to get out of the 50s.

I don’t see much rain out of this cold front tomorrow evening through Tuesday afternoon.  In fact much of the lowlands will see less than a tenth of an inch.  The flow will be strongly “orographic”, meaning the strong west/northwest wind overhead will squeeze a lot of precipitation out of the clouds in the Cascades and Coast Range.  About 10 times as much!

RPM Precipitation Accumulation

Much of this precip moves over the Cascades before snow levels drop much.  There should be enough precipitation left after a changeover to snow that Timberline sees 3-7″ snow and 1-2″ at Government Camp.  That’s from 5am Tuesday through evening.  Here’s the WRF-GFS snow forecasting ending Wednesday AM:

or_snowacc.72.0000

Weak upper-level ridging returns Wednesday through at least Friday, possibly through next Sunday.  Models disagree on whether a quick-moving disturbance late Saturday and Sunday gives us showers.  We’ll see if they get their act together the next few days.  This means that for about a week beyond this Tuesday we won’t get much rain.  Total rain for the next 10 days from both GFS & ECMWF show 1/2″ or less in the lowlands west of the Cascades.

Other than the shot of cold air Tuesday with a bit of mountain snow, nothing all that interesting occurs between now and mid-month.  I don’t see a “stormy Eastern Pacific” pattern setting up through at least the middle of NEXT week.  It’s typically too early for that, but every few years we do get October storms.   There doesn’t appear to be a good pattern for the “October thunderstorms” either.

Summary

  • We’re going to be dry far more often than wet the next 10 days, you will have many opportunities to participate in outdoor activities/recreation.
  • There’s no sign of significant snow in the Cascades the next 10 days (that’s normal for October)
  • Expect lots of sunshine Wednesday-Friday, maybe parts of next weekend too.

By the way, peak color on our leaves tends to occur within the next two weeks, often around the 20th of October.  Of course each tree species is different, but that seems to be the case just about every year.

Chief Meteorologist Mark Nelsen

Recommended for you

Load comments