Slowly Drying Out Tonight

I see dewpoints are SLOWLY dropping off this evening as we get a drift of drier air coming down from the north.  The good news is dewpoints are much lower to our north (low-mid 50s in Puget Sound), and we get increasing north and northeast wind the next 48 hours.  That should bring us back down into “normal” territory by midday tomorrow.  Basically the humid weather is finishing up this evening.  Temperatures are dropping more quickly this evening as a result too.  We had 3 consecutive record warm lows (61, 63, 63) at PDX, which appears to be the first time in 10 years we’ve seen such a warm stretch…and highly unusual for the last half of the month too. 

Two real nice days ahead with slight offshore flow tomorrow and stronger easterly flow on Thursday.  850mb temps peak out near +20 C on Thursday too.  That should push us well into the 80s.  With the decreasing sun angle and daylight hours, it becomes very hard to get temperatures much above 80 over the next couple of weeks.  But conditions are perfect for that to happen on Thursday.  A weak shortwave trough passing overhead Friday morning gives us a southwest push.  Our RPM model and the WRF-GFS say widespread low clouds in the Valley the first part of the day.  That’s a tricky forecast because in early October once you get the low clouds in the Valley they can easily be stuck there most of the day.  I’ll ignore that for now and go for mid 70s.

Beyond that a stronger trough comes through here very late Sunday or Monday.  That’s the next chance for rain.  But it’s not the start of a wet spell…it appears a longwave ridge wants to stay nearby for a good chunk of next week too.   Hopefully it’ll be nice and dry again, although I see the 00z GFS is looking similar to the humid pattern we just had…plenty of rain to the north and warm air down here.

Chief Meteorologist Mark Nelsen

64 Responses to Slowly Drying Out Tonight

  1. High 70°
    Low 58° this morning (looks like it will cool lower than that by midnight)

    The cooler and dryer air feels good.

  2. Hayfork, Calif in Trinity County had a 66 degree diurnal change today

    High: 104 Low: 38

  3. Boydo3 500' North Albany says:

    When this nice weather ends sometime in mid to late October I think I’ll be able to breathe a sigh of relief. We actually will get a nice stretch of dry weather to end the summer. Indian summerish. The fall colors will be really, really fine!

    • Rob "Wrath" S.E. Portland says:

      All this nice weather is going to lull us to sleep, then La Nina takes hold with a roaring jet, increasing systems, and possibilities of wind storms!

  4. Rob "Wrath" S.E. Portland says:

    Red Mound is still 93F as of 7:21 PM!



    MAXIMUM 106R 357 PM 103 1993 86 20 74
    MINIMUM 56 621 AM 44 2007 53 3 54
    AVERAGE 81

  6. 09-29-2010 Oregon Temperature Extremes

    High 97 at Agness
    Low 74 at Red Mound

    High 59 at Charleston
    Low 30 at Seneca

    Largest Diurnal Change: 55 degrees
    Foster Flat (88/33)

  7. Brandy says:

    I noticed alot of you have posted your winter predictions on last post. I was wondering if it is going to be just colder/snowier then last year or colder ect. Then in years past? I have been watching the signs of nature and I have had both frogs and crickets on my porch this year already and nome last year. I know it is weather folk lore but it is fun. Thanks

  8. Low clouds just beginning to burn off here. Looking at the visible satellite it appears I am one of the last spots to do so. 😦

  9. Rob "Wrath" S.E. Portland says:

    12z EURO sure has a rather dynamic looking system off Vancouver Island at the end of the run.

  10. Kyle From Silverton says:

    How long are you going to remain here in Silverton Andrew?

  11. Cgavic says:

    Didn’t the weather people say that this week would be sunny. Period???

    Foggy in sandy

    Actually, I base my lookout on what the national weather service discussion website says.

    • Ryan (Walnut Grove) says:

      Sun is breaking out here on Swan Island.

      This time of year if we have morning clouds it takes longer for them to burn off. In July they burn off around 10-12am. By late September/October they burn off 1-2pm if at all.

    • Kyle From Silverton says:

      Still cloudy. Cloudy and still so it’s still cloudy. :p

      64F and 57F dew-point.

  12. Andrew Johnson says:

    Still in the clouds down here in Silverton. There has even been a little drizzle and mist this morning. Currently 65 degrees.

  13. Jesse-Orchards says:

    I don’t think it’s gonna hit 80 today…

  14. PDX Weather Nut says:

    Would the forecast high of 85 for Thursday break a record? Probably close to one if not …

  15. Low temperature of 74 this morning at Red Mound

    Gotta love that thermal trough.

  16. muxpux says:

    wierd. Longviews in full sunshine, and according to satellite, portland/vancouver still is socked in. thats a pretty rare occurence this summer.

    • Ryan (Walnut Grove) says:

      Not entirely with a rapidly weakening sun angle. Isn’t it pretty common for Longview to break out of the clouds while Portland/Vancouver stay under clouds in Fall/Winter?

      It is technically fall…

    • muxpux says:

      well, usually with a westerly wind, longview gets that marine push up the columbia from the ocean (sort of the opposite from the gorge portland has to its east) which means as the low clouds burn off they tend to linger up here longer.

      i believe today that after the low clouds moved in, the wind switched allowing us to clear out, and leaving portland in a sort of “bowl” not letting you guys clear out as quick.

      just a hunch.

    • pappoose in scappoose says:

      I think you’re correct muxpux.

  17. Clear and crisp 45 degrees this morning at Astoria. Wish I could be at the North Coast today for the 70’s and sun.

  18. RobWaltemate says:

    Wind here are switching to the Northwest, which is what I consider a “summer” type of wind down here. Usually means for us that dry cool air, and not much rain.

    Curently at 3 mile N or Long Beach at 7:48
    Temp 52.8 DP 51.1 presure 30.09 and steady wind off and on at 3-9 mph from NW.

  19. Boydo3 500' North Albany says:

    It would be cool if Mark started a “winter weather predictions only” topic so we could include the winter prediction posts from the earlier ones and have a reference to see who does well and doesn’t. Mark?

  20. Punxsutawney (aka HIOPHIL) at work by Sunset High elev ~280' says:

    I didn’t see the text output for the 00z GFS, but it didn’t look that warm, certainly not cool to cold though. After Thursday, the 06z GFS does not have a high above 80, and after Sunday it doesn’t have a high above 72. In fact the beginning of next week looks to have highs around 60 +- a couple of degrees. FWIW, the extended looks drizzly, and check out the 850mb temps at the very end of the run. Will have to wait and see if the 12z continues the trend and what the EURO thinks…

    • Punxsutawney (aka HIOPHIL) at work by Sunset High elev ~280' says:

      Oh, and right and front of me, next Thursday has a 77. :\

      I would say that’s warm for this time of year.

  21. Rob "Wrath" S.E. Portland says:

    I see the flow has started to turn offshore according to the OTH-GEG Cross Cascade gradient. PDX-DLS isn’t quite there yet, but has progressively weakened now only reading +0.4mb.

  22. Karl Bonner says:

    Wishful thinking forecast:

    Wed-Sat: mostly sunny with highs 80-85 but The Dalles could hit the upper 80s on Thu/Fri.

    Sun-Mon: somewhat cool and drizzly, highs upper 60s west side and low 70s East Gorge.

    Tue-Thu: more warm weather near 80.

    Fri-Mon Oct. 8-11 : first cold snap. Patchy frost in the South Valley with highs only in the mid to upper 50s.

    Tue-Sat Oct. 12-16: true Indian summer, highs mid to upper 70s with fiery foliage.

    Sun Oct. 17: “Winter” begins for the Northwest with torrents of rain.

  23. Kyle says:

    I’ll complain about that time several years ago we were forecasted 2-4 inches of snow and as soon as the NWS issued a WSW the storm de-materialized into nothing. Nada zippo. 😦 :p

  24. W7ENK says:

    [Milwaukie] 9/28/2010
    79.3°F High
    66.0°F Low
    62.2°F Now
    N 11.0 mph at 4:08p

    • W7ENK says:

      I’m curious; Does fog count as a Trace of precipitation if it’s so thick you can see the little droplets suspended in the air, making the grass and trees wet, but not the pavement?

      Just trying to figure out (based on this alone) if yesterday had a Trace, or if I should mark it as dry.

    • CoCoRaHS would have you enter a trace.

  25. 09-28-2010 Oregon Temperature Extremes

    High 95 at N. Fork Malheur River
    Low 67 at Red Mound

    High 61 at Yachats, Timberline Lodge 6K & Mt Hood Test Site
    Low 28 at Beatty

    Largest Diurnal Change: 59 degrees
    Beatty (87/28)

  26. jackfrost says:

    All this dry weather is making for a very tough fall salmon season! I wish it would just rain already! LOL

    • Justin (Brush Prairie) says:

      Sarcasm? We’re finishing up one of the wettest Septembers on record.

    • pappoose in scappoose says:

      Justin, this time of year the fishing community is waiting for fall rains to bring up the salmon/steelhead run. It’s like us weather geeks waiting for wind/snow/ice, it can’t happen soon enough. I love fishing for steelhead/trout/salmon.

    • Rob "Wrath" S.E. Portland says:


  27. 59 here now , but just up the road my in-dash thermo coming home dropped to 55 degrees just east of the BG Lake entrance at 1040pm. Thick ground fog has developed in that area but clear skies here just up the hill a few feet.

  28. W7ENK says:

    The cooler breeze feels so nice! 🙂

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