Light Snow Showers Tonight

December 5, 2016

6pm Monday…

That was exciting earlier today; I think we all saw the snow and it appears just about all lowland areas stayed in the ZERO-1″ range we forecast.  It’s rare to get this lowland snow shower pattern just right.

So where do we go from here?  Basically the moisture supply dwindles tonight and tomorrow, so showers taper off and become more widely scattered.

marksnowovernight

With temps creeping back down close to freezing, a heavy snow shower COULD dump a dusting of snow just about anywhere.  That said, I bet 80% of us in the lower parts of the metro area end up with bare ground in the morning.  The RPM model paints that picture well…only scattered spots get 1/2″ or more, up in the hills

rpm_snowaccum

There is an additional issue.  Lots of wet roads.  In such a chilly air mass, any clearing sky could lead to icing on any exposed surface.  That means your local street could be icy during the morning commute.  OR, it could be icy from 1-3am, cloud cover moves in, and the ice melts.  In general I think we’ll be more cloudy than clear overnight so I didn’t hit the icy streets to hard in the forecast.

To summarize, our GO GUIDE covers it:

goguide

Give yourself a bit of extra time to check conditions (temperatures) before you head out Tuesday morning.  Then plan on some bright sunshine in the afternoon.  Well-deserved sunshine I think!

Chief Meteorologist Mark Nelsen

 


Post your Monday morning snow totals

December 5, 2016

Did you get snow at your home (or work) today?  Some of us did, a lot of us didn’t.  If you got 1/2″ or more put it in the comments below like this:

GRESHAM
1/2″
300′

We just need your location and depth, and elevation if you know it.

Keep weather discussion on the previous or future postings.

images


9am: No Sticking Snow For Most Today

December 5, 2016

Good Morning!

As I mentioned yesterday, if we don’t get heavy enough precipitation to drag down the snow level, the snow level will stay higher today (read in previous post).  That’s exactly what has happened.  Only .10-.15″ precipitation for PDX, Vancouver, & Hillsboro.  In fact Troutdale has only seen a trace!  As a result we’re at the lower end of that ZERO-1″ I forecast in the lowest elevations.  It’s been a mix of rain/snow showers, and the cool atmosphere can’t overcome the breezy/mixing southerly wind we were expecting as well.

This has screwed up the hilltop snow forecast.  I expected 1-3″ up around 1,000′ and above.  The lack of heavy precipitation is putting us at the lower end of that for sure.  So far at 1,000′ at my home (east of Troutdale) I have just a dusting.

You may remember my rant about snow level forecasting in these showery patterns.  We’re doing people a disservice by implying we have more accuracy than we do (in this pattern).  This morning is a perfect example of why forecasters (and the NWS) shouldn’t be forecasting snow level in increments below 1,000′ in a snow shower pattern.  A snapshot at 8:30am:  Staley’s Jct. on U.S. 26 west of Banks…elevation 200 feet.  A snowy road and maybe a half inch on the ground:

us26-at-staleys-junction3_pid2985

At the SAME ELEVATION, but 15 miles east on the west side of Beaverton…all bare and wet with no snow in sight:

26bethany_pid524

Then over on the eastside of the metro area just above Sandy…at 1,200′.  NO SNOW. The white stuff is left over from yesterday’s hail/graupel showers.

us26-at-firwood-rd_pid2331

So what was the “snow level” at 9am???  Under the heavy showers it was near sea level, where very little precipitation fell it was higher, up around 1,500′.  There you go…rant over for now.

THE REST OF TODAY

  1. Snow showers or snow/rain showers continue.  Some maybe be heavy this afternoon with a rumble of thunder if we get some sunbreaks inbetween.  Hail or ice pellets are possible too.
  2. NO ACCUMULATION AT THE LOWEST ELEVATIONS…HIGHWAYS REMAIN TOTALLY CLEAR unless we get hail/ice pellets out of a heavy shower suddenly in just one location.  Evening commute should be fine.
  3. A Trace to 2″ is still possible at/above 1,000′…more the higher you go

TONIGHT

Snow showers continue, could be a dusting on the hills overnight, but nothing likely in the lowest elevations.  Assuming we stay mostly cloudy, I don’t think leftover wet roads freezing are a problem, but I’ll look at that more closely this afternoon.

Chief Meteorologist Mark Nelsen