Wettest Month of The Year

Probably not a surprise, but we are just now entering the wettest part of the year here in western Oregon and Washington.  The new 1981-2010 averages (30 year averages) show that November has once again claimed the trophy for Portland’s wettest month of the year.  Of course December isn’t far behind.  Then it just gradually trails off through late winter and spring.  Interesting that the wettest days of each year (on average) are from Thanksgiving through the first week of December.  Then it’s on to the dry season right?  Not quite.

So how wet does it look?  Actually I don’t see a ton of rain over the next 7-10 days.  Models haven’t been doing too well on the details weatherwise beyond Sunday or Monday.  For example, the 12z GFS had a relatively progressive flow into the Pacific Northwest, while the newer 00z run has far more digging of energy well out into the Pacific, leaving part of next week dry, and not big soakings anytime in the next 7 days.

The setup for the next 3 days is interesting with a surface low moving onto the central Oregon coast Saturday, then sitting somewhere between Astoria and Santiam Pass for the following 24-30 hours.  This gives an easterly flow through the Gorge, upslope easterly flow into north-central and central Oregon, and the possibility for low snow levels on the east slopes of the Oregon Cascades…maybe down to or a little below 2,000′.  Not a ton of moisture to work with, but something to keep an eye on later Saturday night and Sunday A.M. 

The big snow this weekend will be down in the south Cascades.  Our RPM is showing 10-20″ south of Willamette Pass as moisture swings inland around that surface low.

Speaking of the RPM, I’ve finally made a text output product (above) on our new graphics system that works correctly.  You can see 00z and 12z text output for PDX on my weather page here:  http://www.cascadeaccess.com/~mnelsen/markswxlinks.html

It’s on a pulldown menu in the MODEL DATA section.

Chief Meteorologist Mark Nelsen

151 Responses to Wettest Month of The Year

  1. PaulB/Eugene says:

    Late Sun PM:

    Still not seeing any intrusion of arctic air in areas W of Cascades of OR/WA through day 10

    That being said….late Saturday night (144 hours from now) models…such as MM5 GFS 00Z…track a strong surface low across western WA. This system seems as if it will be quite moist…..with precip rates over .1-.2 inches an hour possible over the areas just to the NE of the surface low track and points south. This would be sort of a slam dunk for snow Dec-Feb…..temps will be borderline for lowland snow at this point…it looks to me…with mid-upper 30s and chunky rain more probable…if models trend colder then we could be talking some snow down low…..

    Cascades could get quite a bit of snow…especially S of the low as the colder maritime air works it way in this weekend…..

  2. W7ENK says:

    It just started drizzling here in Milwaukie… so much for a completely dry day.

    FWIW, my mean temperature for the month of November (so far) is only 44.0F, making this the third coldest month of 2011 behind January and February, but not by much. If this cold blast holds true next weekend, that could send this November carreening (plummeting?) to the top (bottom?) of that list.

    Only time will tell…

  3. 00z EURO shows the PV rotating south-southeastward into northern BC/AB. Major Arctic Blast for southern BC, and possibly here as well given 500mb configuration. Ensemble 500mb Height Anomaly is outstanding looking.
    Also models agree on a strong weather system(Finally) around 975-980mb diving southeast into our area. Even though this is not a typical or classic path/track for winds it may be very active.

  4. pappoose in scappoose says:

    900 PM PST SUN NOV 6 2011


    • Josh in Puyallup says:

      There it is folks the NWS kiss of death. Expect highs in the 70’s with crystal clear skies for 2 months.

      In all seriousness. Fingers crossed, toes crossed, arms crossed, and legs crossed.

    • Both 12z euro and 00z GFS show strong looking system dropping down from Gulf of Alaska next weekend. Sure looks colder + active. Stay tuned….

    • W7ENK says:

      I won’t buy it until there’s 3 inches of snow on my street…

      After last winter, I know better!

    • Jake-(Gresham) says:

      I’m curious what December will bring. That’s when the la la land fun really gets interesting and/or depressing lol!

    • Ilya Khleboyko says:

      I hope it’s not this Saturday. Anything but this Saturday. I have a funeral to attend and they’re spreading my friends ashes near the coast. :/

      Apparently this storm is comparable to the 1995/1983/1963/1880 storms.

  5. Benjamin (West Salem) says:

    I am not the best at reading the models, but the last few runs of the GFS have been all over the place and very different from what the EURO has been putting out for the 7 to 10 day period. It just seems like there is a bigger spread of solutions for that time period then normal. just my opinion

  6. 00z GFS looks like potential snow issue next Sunday nite…………. Hmmmmm

  7. o.c.paul says:

    Accuweather is always one of my weather sources this time of year. (along with all the brainiacs on this blog) They always have snow in lala land. Their forecast has snow and rain for the 16th and 17. Wishcasting? Maybe…..

  8. The nicest November weekend weather I can remember, blue skies dawn to dusk Saturday and Sunday. Maybe the twilight can still be seen on the webcam.

  9. Longview - 400 ft says:

    Currently 41.2
    Yesterday’s high – 44.6
    This morning’s low – 32.5

    Rob, keep the postings coming please!!!

  10. W7ENK says:

    I decided to take advantage of the sunny weather this morning and photograph some of the fall color around the neighborhood.


    Being almost the second week of November, it amazes me how many of the trees around here are still GREEN! It seems to me like everything is set back by at least 6 weeks… still.

  11. Garron says:

    What an amazing morning!!!!! Some might argue it’s a little TOO nice, and that it should be raining cats and dogs by now, but not me. Went for the walk, IN SHORTS!!!!! Then decided it would be a shame not to BBQ some rib eye’s on a day this nice, house windows opened. I was noticing that two of my maples haven’t yet begun to turn color all that much, yet the one right next door is almost bare. ( The two maples are protected between houses) Also the seed pods, or those “little helicopter dudes” as my friends son calls them haven’t yet begun to drop yet either from the maple trees. Isn’t it a little later than usual for the seed pods not to have dropped?

    • W7ENK says:

      Hahaha! We posted pretty much the same thing… except I missed you’re part about the ribeyes! So, what time should I head on over? You want for I to grab some beers on the way? 😉

    • Jesse-Orchards says:

      You’re walking in shorts, opening all the windows in the house and BBQing when it’s in the 30s and 40s out? Little cold for that I would think.

      And the reason the trees are so behind, in my opinion, is the extremely late start they got. We have had more than enough cold weather at this point that they shouldn’t be as far behind as they are. I had my 7th sub-freezing low of the season this morning, and PDX is running almost six degrees below average for the month so far. Great BBQing weather!

    • W7ENK says:

      Sure, why not BBQ? I tried BBQ-ing in K Falls one winter’s eve,
      –19F at 4,400 feet… yeah, not so much! After an hour, the meat was still raw and I could comfortably set my hand directly on the grill with the coals burning less than two inches below. I think with temps of +45 or so at virtually sea level, grilling should work out quite well.

    • Jesse-Orchards says:

      Oh, sure. I was just giving him a hard time. Such a Summery post for such pre-Wintery weather!

    • W7ENK says:

      I do think you’re correct in that the late start to new spring growth has led to the late transition from green to color to bare… but it just seems like it’s much TOO late at this point. I mean, it’s nearly the second week of November and many of the trees have yet to change? Aren’t our trees mostly bare by now??

      Karl, you’re our resident expert on this stuff, any insight?

    • Down here it was a pretty darn nice October. Maybe that has something to do with the later leaf drop. My neighbor has two big Red Maples. One was totally red two weeks ago and the other is just now turning. Just individual variations I would say.

    • Jesse-Orchards says:

      I think it’s a combination of the mild nights through the first half of October and the late start to foliage season. Kind of a perfect storm for late fall foliage. Things are catching up pretty good at this point, though. Just about every tree I have seen around town (in Vancouver) has changed. The consistently cold mornings the last few weeks have helped.

      And don’t ask Karl, he’ll just delusionally claim Portland is on its way to becoming the new Sacramento and tell you to plant a palm in your yard. 😆

    • Karl Bonner says:

      Still tons of beautiful colors in The Dalles and the orchards are just beginning to turn (finally!). I think Jesse nailed it, the warm September and mild start to October delayed the onset of foliage a bit this year. I think we still have at least 3-5 days around here before the colors begin to gradually fade out.

  12. Josh (Gresham) says:

    ‎12z EURO! Sub 975mb Low Drops south around hr 168 spreading the cold trough south with it…

  13. Laurie (Sylvan) says:

    I’m in LA where it is pouring this morning. I wonder if this will be another weird La Nina, in which LA isn’t dry.

  14. Chillier than I thought it would be this morning. The temp is 30 here.

    I see the temp is holding at 34 at Kelso with fog now.

  15. 6z GFS is very similar to 00z EURO/GEM in how it handles the 500mb pattern progression, but it is much better than the 00z GFS. The cut-off low dives southeast down to southern California and does not phase back into the northern stream much like the 00z runs showed last night. Next week(Beyond Day 8) we are awfully close to a modified arctic blast. It does appear that perhaps there is some model consensus with the 500mb pattern evolution. I’m a little eager to see 12z runs today.

  16. 00z GFS Ensembles

    6-10 Day 500mb Height Anomaly

    11-15 Day 500mb Height Anomaly

    • Jake-(Gresham) says:

      Not to jinx us but I’d be such a shame if this pattern didn’t hold into December when we can actually have a decent shot of getting some snow!

  17. Muxpux (Longview) says:

    Kelso reporting 34 currently. That’s the lowest the airport has been do far this fall. Should finally hit the freezing mark here tonight. I see castle rock touched 32 then bumped up to 33.

    Here at my place on my (probably inaccurate) station, I got 36.9 but it is only about 5 feet from the house on the front porch. So yeah. Also, clear starry night here

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