9pm Update: No Frozen Precip Metro Area Monday

November 29, 2015

9:00pm Sunday

Most evening models are in now in.  Nothing has changed.  Possible arrival of any precipitation is midday or beyond within the FOX12 viewing area west of the Cascades.  Another big question is whether ANYTHING falls tomorrow.   Our RPM model is dry over the PDX metro area all day and the WRF-GFS has a trace to .04″ by late afternoon.

There is one spot that COULD see freezing rain in the morning; that would be if the precipitation arrives right away 7-9am in the coast range valleys.  Especially south of Grande Ronde.  Even just west of Corvallis could be a place that sees some spotty glaze early in the day

Of course I’m being a bit dramatic with the 1% chance in Portland, but you get the idea.

One other spot where we may see a glazing is tomorrow evening in the Columbia River Gorge.  Both the WRF-GFS and our RPM imply some upslope precipitation running into the west/central part of the Gorge from Crown Point to Cascade Locks.  That would most likely be freezing rain, possibly ice pellets closer to Cascade Locks.  I’ll be keeping a close eye on that tomorrow afternoon/evening for you.

MarkFreezingRain_Gorge

Chief Meteorologist Mark Nelsen


Freezing Rain Monday? Unlikely For Most of Us

November 29, 2015

You may be hearing rumors of something frozen appearing in the western valleys of Oregon/SW Washington Monday morning?  I think it’s pretty unlikely (as of 1:30pm Sunday) because I don’t think ANYTHING will be falling out of the sky…weatherwise at least.  I can’t account for dogs/cats/frogs etc…

I also don’t think the Monday morning commute will look like this…but it’s a cool pic I found online while relaxing with a warm drink:

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HIGHLIGHTS

  • It’s a cold day!  Airmass streaming out of the Gorge is the coldest this season.  Only 40 at 1pm in Portland.  Highs only around freezing in the western Gorge.  Lots of ice likely forming on waterfalls! (hint…please send pics to photos@kptv.com)
  • Another clear and cold night tonight.  A few upper teens again in coldest outlying areas
  • Clouds thicken up right after sunrise, it’ll be briefly sunny Monday AM
  • A shower is POSSIBLE after 10am or so.  Most likely it’ll stay dry
  • At that point it’ll be too warm (that’s IF a shower develops) for liquid raindrops to freeze to objects
  • It’s too warm overhead for give us sleet/snow, anything falling would be liquid

So the point here is that most likely Monday will be dry, but maybe a shower shows up midday or beyond.  Too “warm” at that time for freezing rain.  It will be a very chilly day with the cloud cover…highs the same or even a notch cooler than today!  Note several model forecasts of precipitation placement at 10am…looks pretty dry doesn’t it?  Click on each for a better view.

 

Now Tuesday night, when a more typical wet system arrives, could be a much bigger issue in the Columbia River Gorge.  It’ll be near/below freezing at that time so we could be looking at some freezing rain/ice storm action at that point out there.  More on that later

By the way, so we’re all on the same page, freezing rain is liquid rain that falls into a below-freezing airmass near the surface.  It freezes on contact, forming an icy glaze.

MarkFreezingRain

Chief Meteorologist Mark Nelsen