Unusually Warm Late October Weather; November Likely Starts Cool

7 pm Tuesday

I love it when I’m wrong…at least in this case.  A few weeks ago I figured we had seen our last 70 of the season since a week or two of chilly weather was on the way.  But today we just squeaked out a 70 degree temperature at PDX.  That was due to a very warm atmosphere overhead plus a mild offshore wind.

To show you how unusual today was…note we haven’t had a 70+ day in Portland this late in the season (October 24th or later) in 14 years!

We also saw the strongest Gorge wind so far this season…with gusts 50-60 mph in the Corbett area and Crown Point due to over 7 millibars easterly pressure gradient across the Cascades.  I think that Vista House sensor may still be damaged from last winter since it should have read a little higher (compared to Corbett).  That pressure gradient is dropping rapidly this evening and Gorge wind will turn breezy WESTERLY by midday Wednesday.  That’s due to an approaching cold front and lowering pressures east of the mountains.

This front will arrive somewhat dramatically tomorrow afternoon with a cloud deck turning our skies gray quickly the 2nd half of the day (after AM fog breaks out to sunshine).  I think we could get a shower or two but that should be about it with this system; it’s dying as it moves down over the Pacific Northwest.

Upper-level high pressure will rebuild three times over the next 10 days near the west coast of North America or in the NE Pacific.  Models are in generally good agreement on this, or at least their ensembles are.   First ridge is Thursday and Friday; right over the top of us.  Note the ECMWF ensemble 500 mb height anomaly.  This is a dry pattern for us with no wet Pacific weather systems able to make it to the West Coast

Then after a brief wave of energy gives us lots of cloud cover and onshore flow Sunday (but no significant rain), another ridge develops slightly farther west Monday:

This time it is slightly farther west, so we’ll turn cooler for Monday and Tuesday…but likely dry for Halloween.  By late next week, about 10 days out, ridging seems to want to develop even farther west.  That’s over/near Alaska.  The GEFS & Canadian ensembles have it closer to us.  Note the lower than normal heights in both of these charts out over the Easter Pacific west of California.  That implies some “undercutting” of the ridge by moisture and weak systems.

That’s a cool weather pattern for us in November, but still drier than normal.  This is also somewhat similar to what we saw last December/January (far warmer of course this time of year).  When wet systems would sometimes move into California while cool air came down from the north over much of the Pacific Northwest.  The combination of those two brought us numerous snow/ice events.  You can sure see the drop in temperatures after Halloween on the ECMWF ensemble meteogram:

and the GEFS anomaly chart.

“0” means average temperatures.  Note we go below average in early November as the ECMWF shows.

To summarize.  We have 3 more beautiful days Thursday through Saturday, although with another round of gusty east wind.  This will likely be the LAST of the mild/warm east wind patterns.  Next time that wind comes back it should be chilly…no warm east wind for you until at least the Ides of March!  Rainfall will likely be sparse for the next 7-10 days with little or nothing in the next 7.

Chief Meteorologist Mark Nelsen


35 Responses to Unusually Warm Late October Weather; November Likely Starts Cool

  1. Boring 550' says:

    Mark my words, snow will not stick below 1500ft west of the cascades in the upcoming cold spell. If it did snow this early, it would be a bad sign for our winter anyways. Let’s save these awesome patterns for D-F.

  2. Nahtalkin says:

    Watching the noon time news for the weather report, the lady anchor was very serious in her story telling about a 10 year old driver somewhere back east….wow so glad she filled us in on that important story….

  3. Roland Derksen says:

    My first frosts of the season often come around this time- if skies stay clear.

  4. Andy says:

    Looked at the models a few days ago. Maybe are first frost in most areas and low snow levels in the foot hills. Though a lot can change until then.

  5. gidrons says:

    Uh-oh. Don’t look at the models at a week from now.

  6. Dustin says:

    How long is this heat wave going to last?? This weather is horrific. Again I love Fox12, but what is going on with all these 1rst grade forecasts? Forecast wrong yet again today, I’m in Milwauke, and it’s 74°! It’s funny, I remember a few months ago Mark saying hot weather is “so easy” to predict. Apparently not. LLooks lke we are not going to have anything close to a winter in Portland this year. 😭😭😭

  7. W7ENK says:

    The weather this week, absolutely gorgeous! I’d be commuting by bike if it wasn’t dark so darned late in the mornings.

  8. Roland Derksen says:

    Periods of fog here this morning. The next few days could see fog in the mornings and/or evenings. Perfect weather for Halloween!

  9. High Desert Mat says:

    14 years ago. Nice analog. I could deal with another ’03-’04 winter.

  10. JERAT416 says:

    It sure is hazy in Portland. Is it smoke? Fog? Dust? Quality is 54 currently.

  11. Lee Wilson says:

    well, were running some small items and Halloween Blow Ups off solar power along with a small freezer and electronics.

    as it is cloudy.
    Yester day was great, we were cooking things 🙂

  12. Lee Wilson says:

    Well, after that winds torm, I mlched leaves..ut a second small windtorm..took them off the tree now the ground is soft and “fluffy”. Kind of hard to Mucl leaves when the once try Ground expanded lol

  13. Roland Derksen says:

    Yesterday in the sun I saw the temperature go up to 65F here. Today under low clouds and light drizzle, it will be hard to get past 50F.

  14. Erika says:

    Nooooooooooooooooooooooooooooooooo, we already had too many warm days, we don’t need more, yuck!!! Bring the cold weather already!!!! And more rain too!!

  15. I remember a fairly warm east-wind day in late February in Portland. I think it was 2016…about 60 degrees if my memory is correct.

  16. Paul D says:

    Bring on the cooler weather! I’ve got a new winter coat I’m itching to wear 😀

  17. How often do they need to fix/replace the sensor at Vista House?

  18. JohnD says:

    Thanks Mark. Good stuff.
    Looking forward to Saturday!
    ALSO I have to say that in all my years here as a Western Oregonian, I can’t recall a more vivid fall! Really beautiful!

    • Nahtalkin says:

      I agree, it’s hard to get work done here at the farm, have to keep stopping and take in the fantastic colors and bright sunshine….my favorite time of the year!

  19. JERAT416 says:

    Hey if it’s dry for the trick or treaters, that’s fine with me. Could be worse!

  20. W7ENK says:

    Today’s weather was absolutely spectacular!

    I had to drive to a job site up near Rainier this morning. Hit the road at 7am, I did a big loop up I-205, to I-5, to Longview, across to Rainier, then after the site visit, back down Hwy. 30 to Downtown. Little bits of fog on the way up, blue skies, warm sunshine… but the highlight of my trip was the trees. The fall color is at it’s prime!

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