7pm Sunday...

Today was sure a gloomy day!  It seems like it rained at least a third of the day, but we only ended up with a few hundredths of an inch in the metro area.  That’s a classic warm-front setup

The system changed snow to rain in the Cascades.  After a big dumping above 5,000′ Thursday night through Saturday, now it’ll be mainly rain through Tuesday up there.

A warm but “flat” upper-level ridge is sitting over the NE Pacific Ocean.

That gives us lots of clouds, but not much rain.  Tomorrow another warm front sweeps mainly into Washington.  So we’ll see lots of clouds again but little rain.  On Tuesday a little “wiggle” moves over the top of the ridging and down over us.  At that point we should see at least a few hours of rain.  Then the ridge pops up again a bit stronger and closer to us.  Here’s Thursday, look at those 588 dm heights over Oregon!  

If it was early September we’d see 90s out of this pattern.  Instead, at the end of October, highs somewhere between 65-70 are more likely under dry offshore flow.   This means Wednesday and Thursday feature the best and warmest weather this week.

Then by this weekend the ridge pops up a bit farther west, allowing a cold upper-level trough to drop south out of Canada and into the western USA.  That looks chilly!

These maps are the ECMWF ensemble forecasts, but other models are similar.  Notice the real cold air doesn’t drop right over us, but a bit farther east.  The Rockies and Intermountain region get nailed with cold snow showers next weekend.  This should give us a round of dry/chilly northerly/easterly wind Saturday through sometime early NEXT week.    The result for our area will be a sharp drop in temperatures between Thursday and Saturday/Sunday.  Overnight lows will go from near 50 Wednesday to around freezing once again next weekend.  But not a whole lot of rain.  Check out the change in airmass on the ECMWF 850mb ensemble chart, quite a drop isn’t it?  Just 5 days ago there was not hint this would occur.  That ECMWF wanted to put the ridge right over the top of us, but now wants to dump come cold air south over the West.  This is the 3rd time this fall season we’ve seen this happen.  Very interesting…

Check out the ensemble runs from ECMWF, GFS, & GEM models.  All show 1″ or less rainfall in the Willamette Valley through these next two work weeks.  That’s through the first day or so of November.

 

 

 

 

 

It’s probably a bit premature to mention this, but why not…  It’s interesting that this is the type of pattern we can get during a weak El Nino winter.  Split flow can be common in those winters too.  We are on the warm side of ENSO neutral right now and it seems we’ll be right on the edge of weak El Nino conditions this year.  Just tossing that out there for fun.

Summary

• I don’t see much soaking rain for these last 10 days of October, but it will rain here and there.
• This work week features mild temps, Wednesday & Thursday should be the warmest!
• Next weekend may feature a nice chill; perfect for the weekend leading to Halloween.
• There’s absolutely no sign of a stormy weather pattern ahead.  I’m referring to our usual stormy setup with one area of low pressure after another giving us waves of strong wind and rain.
• Snow in the Cascades will gradually melt over the upcoming week.  A few more inches could fall later Friday or Saturday.

Chief Meteorologist Mark Nelsen