January Ends Mild, But Cool February Start

January 28, 2019

6:30pm Monday…

That gusty east wind did the job as we slept, clearing the fog and low clouds.  Most of us woke up to bright sunshine today.  Portland’s high temp surged from low 40s Sunday to low-mid 50s today.  You can see the cool easterly flow affecting the eastern edge of the metro area; Troutdale only hit 48.

pdx observed high today

That hazy sunshine plus breezy east wind continues through Wednesday morning.   Mild temperatures continue as well.  Most of the Pacific Northwest has been warmer than normal this month.

anomimage

This “cool season” so far in Portland has been the 4th warmest.  That’s from November 1st to now.  That explains blooming plant reports.  Looking around my garden/yard it’s as if it just went to sleep a bit, instead of everything totally dying off.  Looks ready to wake up again soon.

You can see the effect on snowpack.  Mt. Hood has now dropped to only 50% of average, with all of the Cascades well below normal for late January

or_swepctnormal_update

So what’s ahead?  Here’s what I see

  1. There is no sign of typical stormy weather in the next 10+ days; models continue the strangely quiet weather pattern through the foreseeable future.
  2. We’ll likely remain drier than normal in early February
  3. Temps cool below average for at least the first week of February
  4. Right now there is no obvious sign of lowland snow, but it’s definitely NOT time to pull out the “winter is over” fork. 

Today there is a strong upper-level ridge along the West Coast, and very cold trough (an extension of the circumpolar vortex) swinging down through the middle of the continent.

jet stream forecast 2017

This pattern was well-advertised by models 10-14 days ago; they did well with the general setup.  I mentioned last Monday that we would watch closely to see if any chilly air drops south this week (or beyond).  Models were hinting the ridging would back off to the west.  Apparently that IS going to happen.  Take a look at the ECMWF forecast for next Monday

jet stream forecast 2017_2

That general setup continues through the 10 day period on ensemble forecasts from most models.  Here’s Friday the 8th, you see the cold troughing over the West and high pressure in the Gulf of Alaska.

eps_500_fri8th

Beyond that, there are hints the ridge moves back over us or very close by.  This is the 15 day forecast for the 12th of February.

eps_500_tues12th

Last night’s monthly run of the ECMWF showed a similar setup with drier than normal conditions for February.  eps_32dayprecipanomaly

This would continue our theme of a “dud” winter; weak weather systems and no stormy upper-level low sitting over the Gulf of Alaska like we’d see in a normal year.

Of course with a cold trough nearby the next 10 days or so I’ll be watching closely to see if any one system digs farther south and/or combines with some moisture to produce snow down below 2,000′.  At this point nothing looks interesting on any model run.  Part of the issue is that we’re in that somewhat dry pattern the next 10 days.  ECMWF gives us only 1/2″ rain in the entire week from this Thursday to Thursday the 7th; the ridging is still quite close to us.

ecmwf_precip_168_portland_41

850mb temps may drop down around -5 to -6, which is great to get a dusting of snow into the Coast Range summits or even as low as 1,000′ west of the Cascades.  The ECMWF ensemble average drops to around -6 next Monday/Tuesday, but it’s also dry during that time.  With onshore flow and showers you need at least -7 to get excited about wet snow on the valley floor.

kpdx_2019012812_z500_t850_360

So if you’re a weather geek like me, keep a close eye on the next 10 days or so.  This is the type of pattern where something could suddenly change and we get a shot of cold air and/or quick snow.  But at this moment nothing specific is showing up on our models/maps.

Chief Meteorologist Mark Nelsen