snow

7pm Sunday…

Hope you are enjoying the Super Bowl on FOX12 or anything else you are up to this Sunday evening.  I’m on a bit later tonight, around 8:30pm or so once The Masked Singer finishes up.  That gives some time for a quick blog post to let you know what’s up weatherwise for this first week of February

Quite a change today from the low 60s Friday.  We only hit 45 today and we’ll spend most of Monday in the 30s and lower 40s.  A cold upper-level trough is passing over the Pacific Northwest this evening.  Earlier we saw a few scattered showers pop up in the chilly airmass, producing a mix of rain, hail, and graupel.  Those were driven by the increasing February sun angle producing surface warming that bubbled up into the cold air above.  Now that the sun has set, we’re finished with those.

KPTV 2017 Default Earth

We’ll likely remain dry through about midnight.  With partly cloudy skies temperatures fall down to around freezing most areas west of the Cascades too.

Models are in pretty good agreement that the line of showers offshore moves inland after midnight.  These will be light showers, but with temps around freezing ANYONE COULD SEE A BRIEF DUSTING OF SNOW west of the Cascades.  That said, some of us will be slightly above freezing = no sticking snow.  Other areas may get a rain/snow mix, then partial clearing AFTER the showers pass by could lead to a wet road freezing.

The result will be a random mix of four road conditions west of the Cascades for the morning commute in the lowlands from Longview to Eugene:

  1. Dry roads: where showers don’t pass overhead
  2. Snow-dusted roads: snow showers have passed over w/temps near/below freezing
  3. Icy roads: snow/rain showers pass by, then skies clear = black ice forms
  4. Wet roads: snow/rain showers pass by, but temps remain above freezing

All of these could occur within just a few miles of each other so tomorrow morning is definitely the type of morning to keep an eye on your car thermometer and morning weathercasts (here on FOX12 of course!)

And of course I could see a few school delays as well.  But this is not a “widespread snow” sort of weather setup.

Snow Tonight Forecast 1

What are models saying?  They don’t do very well with this real marginal/light precipitation setup so you can’t look at any one specific location and claim it will/won’t snow and stick right there.  But you can get a general idea.  Here’s our GRAF model, the lightest color indicates 0.2″ to 1″ in this case.

GRAF Snow Accumulation

The WRF-GFS thinks most showers go south, a little better chance in south Willamette Valley = no snow for most

or_snow24.36.0000

And the HRRR, just a very light dusting in spots

hrrr_snow7am

The message in general is the same…almost all of us will see our day progress as normal Monday, but a few wake up to a dusting of white.

Tomorrow should be a GREAT day…partly cloudy with a bright blue sky.  Chilly start and end but around 45 mid-late afternoon.  Tuesday will be similar, although lots of us will start in the mid-upper 20s.  I’ll go 28 at PDX for Tuesday morning.  Once again we can’t seem to reach the cold nights we saw back in November.

Winter Coldest Day Each Year

A weak ridge of high pressure sits overhead Wednesday-Friday, bringing a mild south wind and rainy weather those days.

Models are still going for a little cooling next weekend, although nothing that would bring snow close to sea level again.  By next Sunday all models are bringing an upper-level ridge close to us again.  The GFS ensembles shown here for:

gfs_sunday9th

But just 10 days away (Wednesday the 12th), the GFS is trying to bring very cold troughing down over us

m500za_f240_bg_NA

The GEM (Canadian) says nope, ridging is much closer

gem_wed12th

The ECMWF agrees with the GEM, keeping temps relatively mild, but a little on the cool side through mid-February

ecmwf-ensemble-KPDX-daily_tmin_tmax_ecmwf-0644800

We may dry out a bit too with a closer ridge.  ECMWF ensemble average (for Salem) shows only 1.5″ rainfall during the next two weeks.  Operational (blue line) only around an inch.

ecmwf-ensemble-KSLE-indiv_qpf-0644800

By the way, 3 of the past 6 Februarys we’ve seen significant snow in Portland.  We’ll see what happens this month, but nothing suggests we’ll see measurable snow in the first 10 days of the month.

Mark Snow PDX February

Chief Meteorologist Mark Nelsen

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