A Week of Wet Weather Ahead

7pm Tuesday…

Hopefully you’ve paid close attention to our forecasts the past few days.  If so, you’ve finished up any project that requires dry weather and are now ready for a week of rain.  No, it’s not going to rain for the next 168 hours non-stop.  Instead, we’ll see a succession of wet Pacific weather systems moving into the Pacific Northwest.

After a very wet September, the faucet has shut off this first half of October.  We’ve seen little/no rain the past 10 days in the Portland metro area

Rain PDX Last 10 Days

And of course it’s been a very cool 1st half of October; temperatures are running 5 degrees below average at PDX so far… THIS HAS BEEN THE COLDEST 1ST HALF OF OCTOBER IN PORTLAND IN MY LIFETIME!  Only two have started colder, October 1968 and October 1949.  Those were followed by some interesting winters…just throwing that out there.  I highly doubt what happens the first two weeks of October means anything about the upcoming winter.  Notice the last few Octobers have been wetter than average

October Rain Stats

A cool upper-level trough (dip in the jet stream) is sitting in the Eastern Pacific and moves a bit closer tomorrow


Tonight a weather system is sitting offshore; it’ll move inland Wednesday morning.  That system will be quickly overtaken by a cold front by tomorrow afternoon.  So we get two waves of rain tomorrow.  Behind that cold front, Thursday and Friday will feature the usual cold showers mixed with sunbreaks.  Friday night and Saturday a quick-moving trough spins up a surface low pressure system offshore.  Models are showing quite a slug of rain and gusty southerly wind with this one.


That said, I don’t see any hints that we’re entering a real stormy pattern with multiple areas of deep low pressure tracking along the coastline.  We’re just going to see a parade of wet and breezy  systems moving overhead.  In October, in this pattern, it’s possible to get those waterspouts or weak tornadoes too if the pattern is just right.  We’ll be on the lookout for that.

Now that you’ve finished planting your spring bulbs, garlic, or cover crops, you’re probably wondering how much rain is on the way?  Quite a bit!  The WRF-GFS from UW shows less than 2.50″ in the western valleys ending next Tuesday


ECMWF, GFS, & GEM models all show somewhere between 1.50″ and 3.00″ in the western valleys of Oregon and SW Washington.   Maybe 5-10″ wettest parts of Cascades and Coast Range.  This isn’t enough to cause flooding when spread out over a week, but it’ll help recharge groundwater I suppose

This slideshow requires JavaScript.

This is the reason that I’ve been saying to “wrap up all your dry weather projects” by tonight.  It’s going to be quite wet over this upcoming week.

What about more dry days?  Models are suggesting we get some sort of upper-level ridging over the USA West Coast starting a week from now.  All three of the above models show a strong ridge right over us 8-10 days out.  Here’s Friday the 25th

This slideshow requires JavaScript.

It’ll be interesting to see if we get a setup we’ve seen twice this autumn; a trough suddenly comes across the ridge, pushing it back to the west and putting us under cold northerly flow.  There are a few hints of that in the 12z ECMWF ensemble chart; some ensemble members take quite a dip in the 2nd week.

tseries_850t_000-360_Portland (2)

To wrap it up…enjoy your inside time this next week.  And enjoy the gentle Pacific Northwest rains splashing on your roof.

Chief Meteorologist Mark Nelsen

25 Responses to A Week of Wet Weather Ahead

  1. Andy says:

    Having some strong south winds down here in Albany. Is a low forming?

  2. JJ78259 says:

    Beautiful 90 degree weather here San Antonio today!

  3. Joshua Lake Oswego says:

    Bye bye weather for at least 7-10 days after Tuesday. October will end up way drier than normal. At least it has felt like fall and looked like fall.

  4. Jason Hougak says:

    First Winter Storm Warning for the season in the higher Cascades above 5500’ for 10-20”.
    So nice to see Mt. Hood covered in snow so early this season.

  5. runrain says:

    Maybe close to advisory level winds tonight? NWS says gusts to 38 mph.

  6. W7ENK says:


    27th Annual “Winter Weather Forecast Conference”

    From: Steve Pierce
    Oct 18 at 2:05 PM


    Contact: Steve Pierce, President, Oregon Chapter of the American Meteorological Society (AMS)
    KOIN 6 Meteorologist

    27th Annual “Winter Weather Forecast Conference” –
    Saturday 10/26 @ OMSI in Portland

    Portland, Oregon (October 18th 2019) – The Oregon Chapter of the American Meteorological Society (AMS) will host the 27th annual “Winter Weather Forecast Conference” this coming Saturday, October 26th @ 9AM @ OMSI in Portland. Meteorologists from across the Pacific Northwest will once again converge on Portland to give their annual forecasts for the upcoming winter to a capacity crowd of nearly 300 attendees. What lies ahead this winter? Come hear the latest details. Dr. Cliff Mass from the University of Washington will lead off the meeting beginning at 9AM with a special presentation. The Oregon AMS chapter will also be raffling off a $250 voucher to the Tolovana Inn Resort in Cannon Beach, along with a $300 Davis home weather station. This meeting is free and open to all ages of the general public.

    What: 27th Annual “Winter Weather Forecast Conference”
    When: This coming Saturday, October 26th 2019 @ 9 AM.
    Where: Oregon Museum of Science and Industry (OMSI) main auditorium, 1945 S.E. Water Ave. in Portland.
    Driving directions to OMSI: http://tinyurl.com/6rrz8em.
    Meeting and parking cost: This meeting is free and open to all ages of the general public. Free parking in all OMSI parking lots.
    Overnight Accommodations: For overnight accommodations in Portland, please see: http://tinyurl.com/7boqrsf
    Agenda: Meteorologists from across the Pacific Northwest will once again give their weather forecasts for the upcoming winter.

    Who is the Oregon AMS? The Oregon chapter of the American Meteorological Society (AMS) was founded in 1947 and is the single largest local chapter of the American Meteorological Society (AMS) in the country, with approx. 180 members. The Oregon AMS chapter normally hosts meetings from September to May that are free and open to all ages of the general public. The Oregon AMS welcomes the public to become chapter members for just $10 per year. The Oregon AMS chapter mission statement reads, “The purpose of this society shall be to advance professional ideals in the science of meteorology and to promote the development, exchange, and application of meteorological knowledge.” Our meetings are always found on our web site: http://www.ametsoc.org/chapters/oregon

  7. Roland Derksen says:

    I find that some of our colder winters don’t reveal themselves until December. Remember Nov.2008 and 2016? Both milder than average here in BC, but it got cold in the next month.

  8. MasterNate says:

    Pete Parsons winter forecast for ODA does not bring excitement.

    • JohnD says:

      I know what you mean Nate. I’m on Pete’s emailer too and enjoy them–and his work of many years, The current analog is not great. BUT (dating myself) I do remember well the early arctic blast in Nov. 1977 along with the HEAVY PDX snow event then. I was just out of college at the time-holed up-on my way east for a new job. Forecasters missed it up until the event had already begun.
      Otherwise only time will tell.
      It sure seems like the early fall this year is a harbinger of an exciting winter ahead!

      • MasterNate says:

        Like Pete said, he may need to change a couple of those analog years next forecast so hopefully his long range outlooks will change next month. I too am excited about the upcoming Winter. What a beautiful Fall we are having.

        • On the subject of analogs, I believe four of the five winters that have followed Octobers whose first half has been as cold as the one we have just had, have been cold and snowy in the lowlands. Plus it’s looking like an ENSO-neutral winter is coming; many of those have ended up cold and snowy.

        • Larry says:

          rubusleu is this true? do you know which years this occurred? I just want to check the statistics for myself. 🙂

  9. W7ENK says:

    0.40″ of precip at my place in Milwaukie yesterday.

    0.03″ by 6am this morning.

    Rain picked back up just after I left for work. Hasn’t really rained much today, near as I can see.

    Not nearly as wet as I was expecting, based on everyone’s forecasts. So far, this series of systems has been a little bit of a let-down.

  10. MasterNate says:

    New blog by Cliff. The BLOB is dying! Here’s hoping for a cold and snowy winter!

    • Jason Hougak says:

      This blob differs that it’s a shallow layer of warmer than normal water vs the previous blob that was a deep layer of warmer than normal water. If anything it’ll help feed more moisture into our incoming fronts.

  11. Jake in Gresham says:

    Moss powder set on the roof and gutters cleared. Bring on Fall I say. I’m curious what the rain total will be for me a week from now.

  12. j2m says:

    Interesting that both winters of 1968-69 and 1949-50 started out with colder Octobers as both ended up having colder temps and more snow in December/January than most winters.

  13. Lynn says:

    Dying to know your thoughts on winter ❄️!!

  14. W7ENK says:

    This shouldn’t come as a surprise to anyone, it’s about time.

  15. tim says:

    Again, why can’t this possible cold trough happen in December or January i don’t understand . i guess it’s all about timeing it’s just been bad timeing for the past several years now.

  16. JohnD says:

    Very intriguing–as always! Thanks Mark!

%d bloggers like this: