Offshore Flow Kicking In…

snapshotSome image sizing issues tonight, not sure why, but now I’m getting annoyed.  Click on the image to actually take a look.  This is the anniversary of the Yacolt Burn.  Larry from the blog posted the link…lots of info there.  Imagine 370 square miles of forest burning just northeast of the Metro Area.  And that all burned in less than 2 days!  1/2″ ash fell in Portland itself, paint peeled off buildings in Yacolt with the fire only 1/2 mile away.  This was an east wind episode that drove the fire 30+ miles from north of Carson all the way to just east of Yacolt and Battle Ground.

Luckily, for this year, we just had a bunch of rain in the Cascades so fire danger isn’t all that high.  Plus logging practices are quite a bit different.  For example in a dry east wind we don’t burn slash piles as they did back then.  In general people are far more careful nowdays. 

I see the wind is beginning to blow at Larch Mtn (WA) and Three Corner Rock in the Gorge.  I took a hike up to that 2nd spot in July.  A nice view, but it did look like it sure was exposed.  Somehow I missed the RAWS station, must have been gagging on a Clif Bar at the time.  If I recall correctly that was the time I ran out of water halfway through a hike…tough.  Okay, I digress a little bit.  The easterly gradient through the Gorge should go up to 4 millibars or so, enough to get east wind to PDX by midday or early afternoon.  Assuming that happens, the 92 shouldn’t be hard to hit.  We hit 91 last year on the same day!  The 850mb temp was only 18 and tomorrow’s is forecast to be around 21-22.  So the potential is definitely there for 92-96 degrees.  Okay, out of time…need to drive home.

Chief Meteorologist – Mark Nelsen

58 Responses to Offshore Flow Kicking In…

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

    Surface gradients

    As of 8 PM-Current|Hourly Change
    PDX-DLS: -3.0mb | 0.5mb Increase
    TTD-DLS: -3.2mb | 0.5mb Increase
    If the offshore flow persists tonight it is going to be mighty warm east of I-205.

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

    Hmmm well based on the AFD, and your info Tyler I’d say it is at the least a possibility which needs to be monitored. It would be nice to see tonight’s 00z WRF-GFS show CAPE developing further north and also the 500mb model showing S-SSE winds aloft.

  3. Tyler says:

    The GFS shows some QPF early Sunday and then again late Sunday.

    The RPM model shows southerly flow until about 4 am Sunday. Notice it also shows a switch to “onshore” wind tomorrow at 8 AM.

    Check out the WRF from the NWS…the image shows a nice band of precip moving in from the SW.

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

    Excerpt from the NWS AFD


  5. Andrew Johnson (Silverton) says:

    I am at 86 right now.

  6. Punxsutawney (aka HIO Phil at work by Sunset High) says:

    93.1 at my station at 4:00pm

    Station, Temp, 24hr Change, Wind

    HIO, 93, +10, VRBL 5

    PDX, 93, +12, E 15

    VUO, 95, +14, E 9

    SLE, 92, +9, NW 5

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

    Observations as of 3 PM
    Portland 92F
    Salem 90F (Silverton Gardens 88F)
    Vancouver 94F
    Troutdale 89F
    Hillsboro 92F
    Aurora 94F
    Surface gradients

    As of 3 PM-Current|Hourly Change
    PDX-DLS: -3.0mb | 0.5mb Decrease(Peak -5.2mb 10 AM)
    TTD-DLS: -3.2mb | 0.5mb Decrease(Peak -5.9mb 10 AM)
    OTH-GEG: -3.8mb | 0.4mb Decrease(Peak -6.4mb 9 AM)

  8. Tyler says:

    This is about as empty of storms that I can remember the Pacific.

  9. 91.4F here currently with a continuing east wind…

  10. Tetra says:

    It’s 85F now. I wonder why I am not as warm as everyone else.

    It’s too bad we are having ridgey widgey weather. 😦 It’s ridgey widgey time.

  11. Punxsutawney (aka HIO Phil at work by Sunset High) says:

    93.4 at my place in Hillsboro

    Station, 3:00pm Temp, 24hr Change, Wind

    HIO, 92, +11, E 5

    PDX, 92, +12, E 14

    VUO, 94, +13, ESE 9

    SLE, 90, +9, NW 5

  12. Tyler says:

    Finally Vancouver makes it up to 90 with an east wind.

  13. Tetra says:

    *FEELS* more like 85F after walking in the sun.

  14. Tetra says:

    It finally made it to 82.9F here.

  15. Punxsutawney (aka HIO Phil at work by Sunset High) says:

    2:00PM Temps

    91.8 at my station in Hillsboro.

    Temp, 24 hr change and wind.

    HIO, 91, +13, ENE 10

    PDX, 91, +15, E 6

    VUO, 88, +11, W 7 – needs to get in on the east wind action.

    SLE, 87, +9, NNE 5

  16. Might as well chalk up another 90° day…..

    89.3F Td 56.4 RH 33%…east winds to 18mph…

  17. Punxsutawney (aka HIO Phil at work by Sunset High) says:

    HIO on route to 96 today which would be a record.

    Station, Temp, 24 hr change and wind as of noon.

    HIO, 85, +12, E 6

    PDX, 79, +10, NW 7

    VUO, 79, +9, W 6

    SLE, 79, +13, VRBL

  18. muxpux says:

    great weather this weekend for the “end of the world rod runs” at Long Beach.

    always a hit and miss at the coast. one year i remember t-storms and lightning, and last year was drizzly and cold.

    already 75 at astoria!

  19. Anthony Bertolo - Gresham (500') says:

    100 Would be pushing it, but mid-90’s isn’t far off at all.

    I really don’t like what I see in the models. I was looking forward to some Fall like weather but it looks like Summer just doesn’t want to stop, no real sign of Fall anywhere in the forecast (LaLa land has been hinting at maybe a shift but it has been doing that for over a week now).

  20. Christiana--Forest Grove says:

    Rob–Thanks for talking about Sept. 11 as someone who grew up in NYC I can’t ever forget.

    Weather question: heard a forecast that said we could hit a 100 on Saturday. I know that in September it is different to 100 than in July.

    • Jesse-Orchards says:

      Saturday looks like 90 at best.

      We’ve never hit 100 this late in the season, so yes, a mid-September 100 would be different, being that it is climatologically impossible.

    • Punxsutawney (aka HIO Phil at work by Sunset High) says:

      Well HIO has recorded a 100 on the 8th, only 3 days ago. And a 98 on the 16th, and a 97 on the 22nd, so I would not say impossible for the next few days. Highly unlikely, and probably needing the perfect setup of warm overnight temps and offshore flow to happen.

    • Jesse-Orchards says:

      Nah, it’s climatologically impossible at this point.

      It’s never happened in the decades of records we use to define the capabilities of our climate. It has never happened this late in the season, at any major NW Oregon station. Thus, I can say with a fair degree of certainty that 100+ this late in the year is climatologically impossible in our current climate regime.

      No if’s and’s or but’s really.

    • …nothing is impossible, especially when we are in the midst of a record breaking year….perfect setup, yes, it would take that, bound to happen…probably someday!!….
      Ive noticed that when folks say impossible, it just opens the door to possibilities……
      see ya’all with plenty of pics in a week or so!!!

    • Punxsutawney (aka HIO Phil at work by Sunset High) says:

      I would also add that the climate is warmer here currently than in past recorded history, making it more likely that it will happen some day. A slight variation on those days I mentioned and it happens.

    • Rob "Wrath" S.E. Portland says:

      Hmmmm 100F this time of year. I’d have to say it seems very hard to attain, perhaps upper 90s? I do think it is not entirely impossible though rather extremely unlikely.

  21. sundaze says:

    Hey MARK! *^#%#!&% You always do this… OFFSHORE? What do you mean… I can’t tell if it’s coming or going…

    • Mback says:

      Offshore wind, or flow as it is often called, means the wind is coming out of the East and flowing offshore, or off the beaches. This East wind is a warm wind for us in the summer and a brutally cold wind in the winter. To recap, offshore wind is wind coming out of the East and headed to the West, an onshore wind is wind coming out of the West and headed to the East. Hope that helps.


    • I would of hoped sundaze was just kidding because of the Labor Day Laugh thread. I guess you never know.
      Currently 71.1° after a low of 51.9°, light WSW winds here.

  22. Punxsutawney (aka HIO Phil at work by Sunset High) says:

    Cool in Hillsboro this morning. Down to about 53 at my place and 51 at the airport, no wind.

    Warmer and just a bit of a Northerly wind here at work.

  23. Timmy_Supercell (Hillsboro) says:

    Some interesting stuff Mark, didn’t even know about that fire. Crazy.

    Not too many reports came from that line of severe t’storms in ND. South of the ND border, there was a report of golfball sized hail w/ 60 mph winds. Thats the most severe they got last night.

    Speaking of t’storms…

    SPC is forecasting thunderstorms along a narrow strip from southeast CA to the northern OR Cascades. A small trough off the southwest CA coast will be cutting through to the north, feeding some moisture soon.

    Here is the trough now:

    And as it cuts through:

    It starts to fizzle out by hour 54Z.

  24. Kay Bradley, TTD says:

    Worth mentioning – I just noticed Larch Mtn has a yellow caution the on the past two hours’ readings.

  25. Kay Bradley, TTD says:

    Wind and warm temp, mostly, woke me up. Wow. 76 at Larch Mtn, 71 Troutdale, and 61 with west winds at PDX. It will be interesting to see how long this takes to spread out.

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

    Awake to let the Cat out, and sure enough east wind developing and temp up to 65F already and climbing. I see it is 70F in Troutdale and rising.

    Surface gradients

    As of 4 AM-Current|Hourly Change
    PDX-DLS: -3.7mb | 0.1mb Increase
    TTD-DLS: -4.5mb | 0.1mb Increase
    OTH-GEG: -6.1mb | 0.3mb Increase
    If I could have a moment please….

    Today we remember. We remember 9/11. We remember how history was forever changed. How tomorrow seemed so far away. How time seemingly froze. The courage and bravery, the heroes, those who were lost, and lives and families forever changed. We remember… a crime against America, humanity, and the entire world.

    A crime against all races, ethnic backgrounds, gender, men, women, and children alike. We remember that the Human Spirit is strong and will never be broken. We remember that today is a day to reflect, to mourn and grieve, to show sympathy and compassion, to respect others and be peaceful to all. Never forget!


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

    Right now it is a very pleasant 56.1F and I managed to cool the house down to 71F. Perfect for sleeping. I have a feeling though due to increasing offshore gradients that by 4-5 AM my temps will soar into the 65-70F range….

    Surface gradients

    As of 2 AM-Current|Hourly Change
    PDX-DLS: -3.4mb | 0.4mb Increase
    TTD-DLS: -4.0mb | 0.5mb Increase
    OTH-GEG: -5.3mb | No Change

    Good night.

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

    Surface gradients
    As of 1 AM-Current|Hourly Change
    PDX-DLS: -3.0mb | 0.5mb Increase
    TTD-DLS: -3.5mb | 0.4mb Increase
    OTH-GEG: -5.3mb | 0.3mb Increase

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

    Larch Mt.(Washington)

    Up to 76F on the heels of a very warm ENE wind.

  30. Mark Nelsen says:

    I fixed it…usually the image is around 90,000 kb. Instead it was 1.2 megabytes! Just trying to jam up everyone’s connection.

    By the way, Corbett sensor is off right now because the ISS on the sensor needs a new battery (I think). I need to get up there and replace it. So no wind observations for you Rob! What would you do if all the PNW weather obs. stopped showing pressure? That would be a REAL tragedy.

    • Rob "Wrath" S.E. Portland says:

      Mark, thanks for the update.

      Can you stay straight-jacket in a well padded room? Yeah that would be brutal for me.

  31. Tyler says:

    A repeat of the weather pattern at least. Not as much left up there to burn though!

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


    Wow 240,000 acres within 36 hours! I have to admit I knew nothing about the Yacolt Burn.
    Surface gradients
    As of 10 PM-Current|Hourly Change
    PDX-DLS: -2.3mb | 0.6mb Increase
    TTD-DLS: -2.7mb | 0.5mb Increase
    OTH-GEG: -5.2mb | 0.1mb Decrease

    • Jesse-Orchards says:

      Sure would be fun to see a repeat one of these days!

      East winds!!

    • Rob "Wrath" S.E. Portland says:

      Definitely not, but I do like your mocking of my “East winds!!!!!” I never knew you wanted to be in the Atmospheric Wrath fan club. 🙂

  33. …Mark…it’s taking forever to load what you posted…

  34. …first, and last for a week or so…

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