July Weather This Week; Possibly 90 Degrees

7pm Sunday…

Forecasting is quite simple the next seven days.  Strong high pressure is sitting just off the Pacific Northwest coastline.  That’s sinking & drying air, keeping weather systems away.

Jet Stream Forecast 2017

That’s why we hit mid 70s in the metro area today, matching our “warmest of spring so far” 76 degree high.

Tomorrow we lose onshore flow, plus a little warmer atmosphere overhead means we’ll likely see our first 80 degree day of the season.  This would be right about on schedule since the 2nd week of May IS the average first 80 degree date for PDX

Average First 70_80_90 Degree Days

We get some brief cooling Tuesday/Wednesday with onshore flow but that only brings us down to 10 degrees above average.  Thursday through Saturday that upper-level high nuzzles right up to the coastline, amplifying at the same time.

Jet Stream Forecast 2017_2

That means surface high pressure develops east of the Cascades and offshore (easterly) low level flow.   Offshore wind May through September can REALLY heat us up under sunny skies and that will be the case Thursday through Saturday.  Most models show onshore flow returning very late Saturday, or Sunday.

So how warm could we get?  Models are generally showing 850mb temps over Salem around 13 to 16 celsius Thursday, then 14 to 18 Friday and Saturday.  To hit 90 in May, past cases show (with offshore flow) we need to see at least a +15 or +16.  So 90 is definitely in the cards this time around.  I’m VERY confident we’re going to hit 85 later this week, far less confident we hit 91-92.

In the past 7 years we’ve seen at least 84 in the first half of May each year.  That said, we haven’t seen a 90 before May 11th for about 20 years.  There you go, lots of numbers.

Rain is a no-show the next week, which means ending Friday we will have seen only .02″ in three weeks!  That will be the driest April 20th-May 10th on record.  Let’s hope this isn’t a repeat of last year.  It would be nice to see a big soaking at some point between now and mid-June.


Starting midweek I’d say it’s time to begin watering everything you would typically water in summertime; lawns, gardens, very small shrubs/plants you just planted etc…  Trees are fine for quite awhile since we had heavy rain just a month ago.

Both the ECMWF & GFS show no rain for the next 8+ days. Click for a better view

That’s through next Monday.  There are still hints we turn wetter around the 14th-18th.  Both ensemble systems show at least some sort of soaking during that time.  That would be later NEXT week

So enjoy the sunshine this week, again, it’s going to feel like July with probably only one “morning clouds” day.  That’ll be Wednesday.

I’ll be off the rest of this week, back to work next Sunday. I’m turning 50 Monday (old!), and randomly chose a week in late April or early May to use up 4 vacation days.  Wow, I sure didn’t expect the weather to line up like this; I think it’s time to get the Nelsen pool up and running!  I’m way too cheap to use a heater so hopefully nature will take care of that Thursday and beyond.

Chief Meteorologist Mark Nelsen

58 Responses to July Weather This Week; Possibly 90 Degrees

  1. PAUL D says:

    Hey Mark! I think this blog has reached its expiration date. Time for a fresh one! Tell us about the chance of rain for the rest of May.

  2. W7ENK says:

    WRF-GFS looks good for a decent shot at thunderstorms on Wednesday afternoon up the Willamette Valley.

    I fully expect that they’ll miss immediate PDX metro, so don’t get your hopes up too high if you’re in the city.

  3. pappoose in scappoose says:

    A Wet Period Ahead for the U.S. West Coast


    • W7ENK says:

      And folks were all worried that our dry season had set in early… lol

      I’ve lived in the PNW my entire life. 40+ years now, and the long-established norm says we always get a nice week or two in May, but the clouds and rain inevitably come back in time for Portland’s Rose Festival. None of this is abnormal, not by any means.

      • Joshua Lake Oswego says:

        Last year, we had .30” of rain from April 17th – June 6th. Then, we had 1.11” until September 9th. So, 1.41” of rain in about 5 months. The dry season most definitely started in April.

  4. Roland Derksen says:

    Big change here today- morning cloudiness and fresh sea breeze has lowered temperatures significantly. Rain is coming this week by Tuesday as well, apparently.

  5. I was right: made it up to 80˚F here today. Was hiking at Dungeness Spit and it was well into the 70’s there; quite unusual given the strong marine influence.

  6. Joshua Lake Oswego says:

    I am shocked to see Wednesday’s rain fizzle out. Not. At least it will cool down next week. No real chance of appreciable rain until next weekend. I think we know what will happen to that chance as we get closer.

  7. runrain says:

    Portland is 15 degrees warmer than Death Valley at 3pm!

  8. Roland Derksen says:

    I know a lot of people are thinking summer has already begun, but a dry spell in May is no garauntee for a dry summer: I looked at my records and saw a few Mays in the past (i.e. 1983, 1995,1997 and 2012) that had long stretches of dry days, but later had more typical unsettled conditions in June , or even July. So let’s wait a bit and see what happens. I could be wrong- but I’m cautious based on my experience.

    • PAUL D says:

      I keep wishing we would have a normal or below normal summer, but I don’t expect it anymore. The new norm is here to stay – like it or not.

  9. PAUL D says:

    The last three years the grass needs mowing by the first week in February and we keep having warmer and drier weather during spring. The July 5th “summer switch” seems to be a thing of the past. Looks like the new normal is here to stay.

  10. 49˚F overnight after a high yesterday of 78˚F. Will probably break 80 this afternoon, depending of course on the sea breezes (or lack thereof). Impressive how toasty it got on the Oregon Coast; obviously they got subsidence from offshore flow descending the Coast Ranges.

  11. pappoose in scappoose says:

    505 PM PDT THU MAY 9 2019


  12. WEATHERDAN says:

    My kind of weather. Memorial day weekend looks nice after maybe some rain around the 18th, Peace.

    • Anonymous says:

      I sure hope so. It’s not the 80+ temperatures in May I can’t stand, it’s the bone-dry summers choking on smoke through most of August I can do without. We need a wet May and June to get the forests good and damp before the normal summer dry spell sets in.

    • I sure hope so. It’s not the 80+ temperatures in May I can’t stand, it’s the bone-dry summers when we all choke on smoke through most of August that I can do without. We need a nice, damp May and June before we head into the normal dry July and August weather.

  13. Roland Derksen says:

    It appears our first 80 of the year will come today. Oh well- it’s not the earliest on record.

    • 76˚F at my place but 81˚F at the nearest automated weather station (which is also on Bainbridge Island). And I’m sure both readings are accurate! Welcome to the world of microclimates and sea breezes. Anyhow, looks like I won’t hit 80 today but probably will tomorrow and Saturday.

      • Roland Derksen says:

        We made it above 80 today; I reached 81.9F. I’m with you about the smoke. So far it’s nice and clear, but if this weather keeps up we’ll be back into smoky skies this summer.

  14. Joshua Lake Oswego says:

    First Red Flag Warning of the year. In early May. Brutal.

    ‘’It should be noted that observed 100-hour fuel moisture values as of May 7 were typical of mid to late July and were close to record low levels for this time of year.’’

  15. david wilson says:

    in vegas its just sunny, temp don’t care, and yes NO EAST WIND!
    hi mark its no hair guy who just sold house on salzman to your friend. on the road 30 years there, now just gone. The great basin was so cool. wife got mad cause i kept stopping

  16. Tanis Leach says:

    While a lot on this was wrong, its turning out the 90 on Friday will likely be true. Forgot that I called for it last Thursday. Ignore the blackouts as I’m protecting private group chat info.

    And when I said I’d fork spring, I couldn’t do the same as winter, so I said spring is grilled (yes I know I said wait and see, but it’s not looking good for rain chances)

  17. Roland Derksen says:

    Perfect summer temperature here this afternoon: 73F. I’m expecting 80 by the end of the week.

  18. I still read this blog religiously even though I moved away from the PNW last summer. The climate in South Dakota is VERY different; it actually snowed for about 15 minutes this morning, with more in the forecast tomorrow. I’m loving it, though. Happy birthday! I also just turned 50 myself; we aren’t old, merely well-seasoned. Enjoy your vacation!

  19. High Desert Mat says:

    Happy birthday Mark. It’s been a great almost two decades following this blog. I may not chime in as much as I used to but still read along almost daily. Thank you

  20. Mike says:

    I’m doing a lot of trail clearing in low elevations near 58, and there is a huge amount of dry fuel on the ground. Stream flows are down, and it won’t take much to have a fire close 58.

  21. Tanis Leach says:

    Happy birthday Mr. Nelsen!

    90 seems inevitable now in the South Valley for Friday and possibly Saturday

  22. Roland Derksen says:

    I could see my first 80 (or 80+) temperatures by the end of the week. That’s warm enough for me.

  23. Dean Suhr says:

    Happy birthday … have a great week.

  24. Anonymous says:

    Happy birthday Mark!

  25. W7ENK says:

    Beautiful warm sunshine, perfect weather to resume commuting by bike!

  26. PAUL D says:


    • Garron near The Hilsboro airpirt says:

      Hope you are having a great time on your special day! Mine is the 8th. I ‘ve lost track of just how many sunny and warm Birthdays I’ve had n the last decadebut it has been a great run! Not the typical early May weather we experienced as kids, that is for sure.

  27. Happy Bday, Mark! Enjoy the week of early summer.

  28. J. Patrick Moore says:

    Mark, you have made my wife interested in the weather, and for that, I am eternally grateful. Best wishes as you enter your second half-century!

  29. Anonymous says:

    Happy birthday

  30. Joshua Lake Oswego says:

    Happy Birthday, Mark! Big day.

  31. JohnD says:


  32. Mariel Walters says:

    Happy birthday, Mark! I very much appreciate your weather blogs and wish you many more years of good health and happiness. Here’s to a safe and joyful year ahead for all of us.

  33. JERAT416 says:

    Death ridge needs to die!

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