Marine Inversion Is Gone = More Sunshine

Making my forecast here at 3:30pm (I work Sundays-Thursdays now) and I’m noticing it’s sunny just about through our whole viewing area.  This is on the day that we figured would be quite cloudy and cool.  We got the cool part right; but not the clouds.  I doubt anyone is complaining but let me explain…

During a good chunk of the summer we are under a marine inversion…quite strong on the coast and it comes/goes in the valleys.  That means relatively warm air is sitting over the Pacific Ocean-chilled airmass down near sea level.  But you can see what has happened today on the Troutdale profiler image below.  Time goes from RIGHT TO LEFT on this graphic:


This is temperature (well, virtual temperature but more/less the same thing) and wind direction/speed from the surface up to around 5,000′.  Note that yesterday AM/Midday it was cool above up around 4-5,000′, as you would expect.  But there was a second area just about as cool down around 3,000′.  That was the top of the “cool” marine layer.  It mixed out nicely in the afternoon, but you can definitely see the weak inversion.  Today is totally different with much colder air arriving above 3,000′.  You can see temperatures go from real chilly at 5,000′ up to reasonably cool down here at the surface AM/Midday today.  The result is a weak to non-existent marine inversion today.  That allows mixing and drier air to break up the cloud cover.  The end result is a sunny and pleasant 2nd day of the 3 day weekend!

The next 2-3 days appear to be similar, so I’m sticking with the morning clouds to afternoon sun routine through Wednesday.

Chief Meteorologist Mark Nelsen

43 Responses to Marine Inversion Is Gone = More Sunshine

  1. runrain says:

    Get out the hot chocolate, blanket, portable heater, and a good book because it Juluary Time!!

  2. WEATHERDAN says:

    71 and sunny at Noon. On our way to 82. This weekend we should get some much needed showers. Maybe .50 before we dry out early next week. Another but much weaker ULL is on tap for the middle of next week. We look to finally get back to normal by mid July. That is to say low 80,s. This upcoming round of precipitation is not unprecedented,nor is it all that unusual. We normally get about .40 of precipitation each July.. In the very hot Summer of 2009 we had one Sunday with over a half of an inch of rain and the afternoon was a rain cooled 58 degrees. In the also hot Summer of 1987 we had a Friday through Sunday July rain storm with over 2.5 inches of rain. So uncommon yes, unprecedented no. No heat wave on the horizon so enjoy the sunny day for the rainman commeth. Peace.

    • W7ENK says:

      So, you just cherry-picked two Summers more than 22 years apart in order to try and prove that this unseasonably cool and wet period that looms near is “not unprecedented, nor is it all that unusual.”



    • JJ78259 says:

      I wonder if July will be below normal temp wise. Most likely not in Salem!

  3. Dizzyland says:

    If Paul takes a trip in January to warm up south I bet we will have the overdue cold spell the Paul Haul. A Haul of cold air just pouring in bringing lots of low level snow 🙂

  4. Dizzyland says:

    Usually it just makes it a tad muggy down here in the valley.

    It’s been on the muggy side the last few days except at night but in the afternoon if you do any hard labor you’ll notice and so had other people.

    Last week it was dry a lot in the afternoons with humidity down to around 30 percent and felt much better.

  5. buffedman says:

    July Or January?

  6. Tyler Mode in Battle Ground says:

    47.5 for a low here in BG. 4th low in the 40s this month.

  7. I wouldn’t say yet that we’ve seen our warmest temperatures for the year. My general rule is to wait until mid-August (August 16th if you want to be specific). Of course, you get on occasion an unusual summer like 2011, where the warmest came in September, but that’s really rare.

  8. W7ENK says:

    Looks like a highly unusual, perhaps — dare I say — fairly unprecedented cool and wet period coming up for late this week, through the weekend and into next week. Temperatures 10 to 15 degrees below normal possible, with anywhere from 1 to 3 inches of rainfall, depending upon where you are. Sadly, the bulk of the moisture looks to dive to our South into Northern California… right where I’ll be camping starting Saturday.

    FML 😡

    • W7ENK says:

      This is what our forecast is supposed to look like in July.

      Unfortunately, not so much this year…

    • Boydo3 N. Albany says:

      I honestly doubt we get that much rain. But it will be funky at the coast. Bring a few extra tarps. And tequila.

  9. runrain says:

    By the time these upper lows stop dropping south from Alaska, it will be September and we’ll be entering fall-type weather anyway. Is it possible summer is over? Are the warmest days of the season behind us? Could be!

    • Boydo3 N. Albany says:

      Nope. In a couple weeks we will all be longing for this once again. Summer will return with a vengance! MARK MY WORDS!!! (or maybe not 🙂 )

    • JERAT416 says:

      No way summer is over! However, what I’m afraid of is HEAT! I’m thinking that we have a few nice days in the 80’s before the thermostat is turned up to where 88 or so looks cool. We will be baking but not hit 100 again this year I expect. Our indian summer will extend into late September/early October with days comfortable but cool nights, then the rainy season starts. Just my prediction. I’m banking on the end of next week to be sunny and warm since I’m hosting a group float down the Sandy River. Happy wednesday everyone!

    • runrain says:

      NWS is using terms like “gloomy” and “May-like” to describe our weather over the next several days.

    • runrain says:

      …and “damp” and “dreary”

  10. Wendy-Silverlake, WA says:

    Question for those of you in the Portland area that know the geographics of the area. Not trying to ask a dumb question, but it will probably seem that way.

    On Saturday there is forecasted rain in the morning then showers. We are supposed to go to Oaks Park on Saturday and so my question is when there are showers forecasted what are the chances that that particular area will see them. I know around here my house will be completely dry (usually) but five miles down the road it will downpour (usually) as that is the way the hills are. It’s pretty much the way it always is (with a few exceptions) so just wondering what the usual geography of that area may be. I hear about the dome all the time, but really don’t know where that is. Thanks for any advice you can give.

    • runrain says:

      You’ll be very close to The Dome. About 3-4 miles south east of there. You might even see Erik riding his bike home on the Springwater Trail. If you have time, there are some nice trails around the lagoon at Oaks Bottom. Or, walk down to Sellwood Marine Park and then over the new Sellwood Bridge. Some excellent views up there and you might still see the workers demolishing the old bridge. Upon viewing that old bridge from the new one, you might wonder how they even let people continue to use it over the recent past. It looks pretty ragtag!

  11. WEATHERDAN says:

    70 and sunny at 1:00 PM. 53 this morning felt good. Just wrapped up a very nice Independence Day weekend. Over the 4 day weekend it was 83, 87, 80, and 75 and was mostly sunny as well with just a few morning clouds. Looks nice this week then some showers this weekend. Next week looks like sunny and back up to around to around the low 80,s. Not that bad for early July. No big heat in sight but I am sure we will see some 90,s by the end of the month. Amazing what a big difference 50 miles makes. Portland and North seemed to have been a lot cloudier and cooler than from Salem and South. This week looks to continue that trend. Weather always amazes me. Peace.

    • It’s really not so unusual. Thanks to the lower Columbia River valley providing a conduit for marine air, Portland has slightly more marine influence than places to the south of it. This is reflected in long-term averages.

      It can be dramatic when it happens, but it doesn’t always happen, so the difference in long-term averages is only 2 ˚F or so.

    • Dizzyland says:

      I’ve notice that too. It has been on the muggy side in the afternoons but mornings and evenings have been excellent.

    • Chris s says:

      Yep Alter Dan, just keep wishcasting those 80’s next week, your warm bias is really getting to you and your so called forecasts. But hey you’ve been wrong for many weeks in a row, so keep trying lol😂

    • WEATHERDAN says:

      Christine where is your forecast? All you ever do is complain of others. Maybe you should just shut up if you can’t come up with your own forecast. I said we would reach as high as the upper 80,s over the holiday weekend, .Oh no you cried, couldn’t happen. Well Saturday it was 87. By the way don’t sit down too hard or you will crush your brains.

    • Chris s says:

      No Dan, I just point out your warm biased and incorrect forecasts which change everyday based on what the gfs says😂 And again I’ve stated many many times this will be an avg summer temp wise, and sorry I don’t make a forecast every 6 hours like you, as well I hate being wrong so much like you are. Great, 1 87 and you think you’re a genius. Meanwhile you called for 90’s for one week and it ended up being around 70 during those days!!!😂😂😂lol keep up the good work though!

  12. Mostly a nice weekend in the Fraser Canyon of BC. Heading north from Hope on Friday, the edge of the marine clouds was visible. By the time I got to Boston Bar it was blue sky and sunshine. Had a few sprinkles on Sunday but they were brief and things dried out fast after they wound down. My truck now sorely needs a bath given how dusty it got exploring forest service roads.

  13. Tyler Mode in Battle Ground says:

    I just turned my heat on. On July 5th. A year ago it was 95.

  14. Not used to seeing all these clouds in July anymore, but when I look back on this date in history, I know it can get a lot wetter (and cooler) than this: July 5, 1987 I saw steady rain til early evening (1.12 inches) with a maximum of 56F. ( And only a 2 degree spread between that high and the minimum for the day of 54F)

  15. Tyler Mode in Battle Ground says:

    Chilly morning, a low of 46.5 today. The coldest it got down to all of last July was 49.2.

  16. schmit44 says:

    The hard to predict stratus field has finally decided to rear its ugly head on the 4th of July. Still overcast and 64° at 3:10pm up in Battle Ground area. I bet there will be more forecasting errors coming these next two weeks with upper lows hanging out nearby.
    Seems like the last 3 days were nicer than expected so today we paid the fiddler so to speak. Seems like the last few impulses that rotated around the upper low over BC came in at night on a 24-hour cycle and had cleared the area early enough in the morning to get the burn-off (Fri/Sat/Sun). Today’s wave came in with a cooler air mass and a bit later around daybreak which delayed the clearing 3-5 hours making it quite cloudy and cool all day. This wave was just bad timing for anyone north of the 45th parallel as most of the state was beautiful today south of about Woodburn/Salem.

    • Boydo3 N. Albany says:

      Yup. Pretty nice down here today. Realy nice actually compared to last summer. Seemed alot like the July weather of many years ago…

  17. buffedman says:

    Julyuary hits Puget Sound, what a difference a year makes.

    • JJ78259 says:

      La Niña has kicked out El Niño that is the difference, showing up very nicely on the Map. Weather Dan should head down to San Antonio nice warm 100 degrees with a great breeze no jacket required for the fireworks tonight!.

  18. Paul D says:

    Over the past couple months I have made predictions about July being cooler than normal this year. I’m not in the business to forecast the weather, and certainly not months in advance, but for one reason only did I forecast for July: I won’t be here most of the month. The last time I left on a long summer vacation was 2011, and we all know what happened then. Looks like once again I will be missing some really comfortable temperatures.

    Oh well, gotta go see other parts of the country sometime…

    So for all of you that hate the cooler temperatures, please feel free to blame me 🙂

    • Have a great trip, Paul- and no, I at least won’t blame you for the coolish July. There were 3 consecutive hot and dry ones, so it’s nice to have a change. (as long as it’s not as cool and cloudy as July 1986 was for me. 🙂

    • No blame, this is much better than the heat and dryness last summer. Plus there’s always the option of heading east of the mountains. If it’s a chilly summer on the west side that generally means a sunny one with pleasantly warm but not hot weather on the east slopes. I spent a delightful week camping near Cle Elum in the summer of 2011; the weather was just about perfect in the ponderosa pine zone.

    • Dizzyland says:

      We can call it the Paul D Cold Blast! 🙂 Please take a vacation in January or December!

  19. High Desert Mat says:

    Mark is bored today. This weather is really boring. I dont blame you Mark, for in the dead of summer it usually I. Thanks for the info anyways though, you teach us all so much.

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