9:30pm Thursday...

It's been a busy week! I'm more regularly on the 4/5/6pm shows plus the 10/11. Not as much time for blogging on the weekdays so I'll make it brief tonight. But you can find me on TV of course!

We are in a classic gloomy weather pattern right now. Strong high pressure offshore at the surface and overhead is blocking storminess. But it's a "dirty ridge", meaning lots of clouds and a little bit of rain makes it over the top.

Satellite PACNW.png

This pattern holds through Monday! I've seen this setup in the past; almost constantly gray skies west of the Cascades but not much rain. Head up into the Cascades, foothills, or Coast Range and things turn wet quickly. Check out the precipitation forecast through Sunday. It's a highly "orographic" rain pattern meaning that almost all the rain falls in these spots.

GRAF_RAIN_NWOREGON.jpg

You want to find sunshine this weekend plus dry weather? Head east of Hood River in the Gorge or into central/north-central Oregon. No rain there.

So we have a big upper-level ridge offshore, and a deepening upper-level low over the center of North America

500mb_fri.png

Here comes the polar express! Bitterly cold air is about to pour into the central/eastern USA east of the Rockies. This is a chunk of the coveted "Polar Vortex" spinning south into southern Canada. Looks like it's going to sit over there for quite a while.

ecm_500mb_FRItoMONLoop.gif

Models are edging the cold air quite close to us Monday-Tuesday. Any closer and we'd be into a full-on arctic airmass. At this point it appears some of the cold air will be pouring into Eastern Washington/Oregon Tuesday. Cue the cold east wind through the Gorge Tuesday & beyond! We haven't seen much of that during this very mild winter.

Jet Arctic 850mb Temps2.png

How cold? Tough to tell right now (5-6 days out), but I think we at least have a "cold east wind period" on the way. That would be highs in the low-mid 40s in the metro area and widespread 20-28 degree lows. Add in a strong east wind = chilly! GFS is very cold again tonight, pushing -16 degree 850mb temps up against the east slopes of the Cascades and a -11 over us. It seems to be extra cold as we approach events, so I'm not sold on that. The WRF-GFS is ridiculously cold as well, that was a problem last winter. It'll warm as we get closer.

gfs_850thursday.png

ECMWF is likely more reasonable; chilly, but not extreme for midweek. This evening's GEM model was a bit milder than this.

ecmwf_850wed.png

I'm noticing low dewpoints on all models, that would be a refreshing change to our current moist/mild regime.

BIG PICTURE

  • We have 4 more mainly gloomy days ahead...if you need sunshine and guaranteed dry, head east of the Cascades
  • A change to sunnier but cool weather should show up Tuesday and continue for at least a couple of days
  • Prepare for the strongest east wind event we've seen in the Gorge since around Christmas. It's been a relatively quiet east wind season. Looks like that'll change middle of next week.  Here's the Vista House peak wind gust chart for the past two months
vistahouse.PNG
  • A few model members are attempting to bring in moisture over that cold air sometime a week from now or beyond. I'll take a much closer look Sunday evening when I have more time, but something snow/ice-wise might be up for the 2nd half of next week...maybe.

Have a good weekend!

Chief Meteorologist Mark Nelsen

Copyright 2021 KPTV-KPDX Broadcasting Corporation. All rights reserved. 

Recommended for you

Load comments