Afternoon Update: A Rainy & Windy Night Ahead

January 10, 2014

4:30pm Friday…

Just checked satellite pic and latest model info…everything is still on track for some strong wind at the coast and gusty wind here in the valleys the next 24 hours.

The highlights:

  • Turning windy and very warm overnight.  Temps remain near 50 or even warm well into the 50s
  • Heavy rain doesn’t really get going until after midnight.  So more dry than wet until 1am or so.
  • Strongest wind at the coast around 1am, a lull, then it picks up again around sunrise.
  • Strongest wind in the valleys between 1am-4am, then it quiets down towards sunrise.  Back to gusty again (but not as strong) the rest of Saturday
  • Rain to snow in the Cascades around sunrise, then heavy snow the rest of Saturday through early Sunday.
  • 15-25″ likely by the time it dies down Sunday evening.

Details are in the graphics:



Look at the latest satellite picture:



The surface low shows up nicely around 145W (way out there) and 47N.  That’s just about where it’s supposed to be according to models, maybe just a touch south.  But not enough to have an effect on a forecast.

We get two strong surges of wind, one between the warm front this evening and just ahead of the cold front that moves onshore around 1am.  That may or may not be the strongest for both the coast and the valleys.  That’s because with this particular storm we have a huge wind field moving onshore with the occlusion well behind the cold front.  That’s the 2nd chance for strong wind during the daytime.  I left peak gusts at 40-50 mph in the valleys due to a relatively weak OLM-EUG gradient of 10 millibars with the cold front.  But then the gradient ramps up to around 15mb midday.  We could easily see a peak gust around 50mph here in the valleys with the showers tomorrow; at that time it should be a real gusty wind with calm periods mixed with the strong wind.   So one spot may have a peak gust of 50 but another only gets 38.  My prediction is a gust to 42 mph at PDX.

Gusts above 40 will definitely do some natural tree pruning in our area since we’ve had such weak wind this winter.

The strong westerly wind behind the cold front runs right into the Cascades….which equals BIG DUMP OF SNOW!

Here is our RPM forecast:


It forecasts 15-20″, almost all of it above 4,000′.  The UW WRF-GFS is heavier:


forecasting 20-30″!  It’ll be interesting to see if this is enough to get the lower ski areas operating…I hope so!

Enjoy the stormy weather because the following 7-10 days look real quiet.

Chief Meteorologist Mark Nelsen