A Soaking For Some Wednesday

10pm Monday…

Today was a nice day; brief morning clouds then afternoon sunshine.  A perfectly normal late August day with a high of 81 degrees.  It appears we’ll likely have more than our typical yearly allotment of 80 degree days.  In a normal year we get 56 days at/above 80 degrees in Portland.  Today was day #48.

80 Degree Days SO FAR

The weather pattern over the next 7-10 days continues to look somewhat on the boring side for meteorologists.  That’s except for Wednesday.  An surface low pressure system is developing well offshore.  It showed up very nicely on GOES-17 imagery just before sunset


The bulk of that system’s rain heads just north of us.  But there is an unusually high amount of moisture with this system.  Plus some of the highest sea surface temperatures I can remember are in place across the eastern Pacific offshore.  Buoy 89, about 100 miles west of Tillamook, is reading a water temperature of 67-68 degrees!


Here’s a forecast from the ECMWF, giving us around 1/2″ rain Wednesday, with up to 1″ or so on the northern Oregon coastline.


Some models are slightly wetter, some a bit drier.  The effect is the same

  1. ) Our very weak fire season will get beaten back once again.  As of this moment there is only one large fire actively burning in Washington and Oregon!  And that isn’t being actively put out since it’s in the Wallowa Mountains.  These occasional shots of light showers and higher humidity are helping out this summer.
  2. ) Everyone west of the Cascades gets at least a dust-settling rain.
  3. ) Southwest Washington, especially north of Longview, could see well over 1/2″ of rain, a nice late-summer soaking.

It’s quite clear that this is a one-shot deal.  Take a look at 50 members of the ECMWF ensemble run this morning.  Each horizontal line represents 24 hour precipitation from one of the ensemble members.  Then at the bottom you see the ensemble average.  It looks very dry Thursday through much/all of the last full week of August.


All of the global models say the last full week of meteorological summer (next week) could be hot as well.  That said, MANY times this summer they have tried to shove a hot ridge of high pressure right up over the West Coast.  They were only right way back in early June.  This morning’s run of the ECMWF showed a hot pattern developing by next Monday


And still there next Thursday, 10 days away


Both maps are hot, even for late August.  We will see…

Chief Meteorologist Mark Nelsen

42 Responses to A Soaking For Some Wednesday

  1. runrain says:

    I glance at Barrow, AK temps every now and then and have noticed they’ve been above freezing for some time now (nights included). I wonder what they’re record is for length of time above freezing. This year has to be close to a record.

  2. W7ENK says:

    Closed out yesterday with only 0.11″ of rainfall. Much, much lower than expected. Such a disappointment, it wasn’t nearly enough free sky water to warrant skipping the expensive municipal water for my garden.

  3. Roland Derksen says:

    I ended up with 0.74 inches of rain yesterday. Not bad- it was my wettest day since April, so the moisture was well needed. As far as the whole year goes, however, we’re still well below average. Another day like yesterday before the month ends would be good, but it appears we’re going to go out on a heatwave.

  4. 00z GFS Ensembles
    Confidence for a heatwave is increasing beginning around next Tuesday with temperatures soaring into at least the mid-upper 90s. It is worth nothing there is a cluster of ensemble members from +20c to +23c good for the low 100s. If models continue to show this the next 2 days I would say to prepare for hot to VERY hot weather.

    00z ECMWF
    Very hot run. Heatwave begins Tuesday and lasts for at least 5 days. Temperatures at least mid-upper 90s. That’s assuming the upper level pattern persists as shown. Confidence increasing. Not a lock yet, but close.

    • Joshua Lake Oswego says:

      The models have been advertising this heat wave for what seems like an eternity. It’s going to happen. We almost got through summer without one. Time to pay the piper. I feel strongly that it will last longer than what is currently forecasted. Let’s go with a full week at or above 90.

    • W7ENK says:

      Summer’s last gasp?

    • runrain says:

      We gotta have one 100 deg day each summer. I can make it through one. Now if we have multiple 90 deg days coming, I might get a tad grumpy!

  5. MasterNate says:

    Finally received a decent shower. That red anomaly off our coast sure is scary looking. I hope that disappears before winter or our snow chances, if any, will be reduced even further

    • W7ENK says:

      One good windstorm offshore should churn the water up enough to erase a good chunk of that. That happened a couple years ago. We learned that the warm surface anomaly is only a few feet thick.

  6. boydo3 says:

    Good soaking here on the south coast. Much more than the forecast.

  7. Jason Hougak says:

    Raining good in Eagle Creek right now. Why is Portland radar so unreliable.

  8. MasterNate says:

    Disappointing, not even a dust buster.

  9. JERAT416 says:

    Bust? Had some drizzle earlier but so far this is pathetic.

  10. PAUL D says:

    HOLD ON! We have rain in Hillsboro! Not much, but the ground is wet.

  11. Larry says:

    Dense fog followed a minute long downpour at my house. Rain arrived a lot later than expected. Seems like a bust rain event to me.

  12. W7ENK says:

    The Dome working hard today? I know PDX radar is down, but it’s not raining here anyway… 🤔


  13. Nice and wet up this way this morning.

  14. Gene says:

    Nothing wrong with AC at 78 if it’s in the 90s outside — it still feels pretty cool by comparison. And if the temps are in the 80s outside, you don’t really need AC at all in Oregon. Just open a couple windows and let nature’s air conditioning do the trick

  15. runrain says:

    Hot stretch coming up next week starting Tuesday. Not all that hot during the day but the overnight lows Tue/Wed/Thu could be really uncomfortable. Especially since those new energy guidelines tell us to keep our thermostats at 78 deg – ha!

    • Evan -- Cedar Mill says:

      Dont forget the urban heat island!

    • PAUL D says:

      I saw that article – hilarious! And you’re supposed to turn it up to 82 at night!

      • J. Patrick Moore says:

        Well, why don’t those people make a real point about it by turning on their heat pumps in the summer and roasting their brains at about 105 degrees, then turn them down in the winter and work in their offices below zero? Makes about as much sense as their guidelines.

    • boydo3 says:

      My thermostat is off.
      I live at the coast. :}

  16. Roland Derksen says:

    I’m not expecting a lot of rain here tomorrow- okay maybe a third of an inch or so, but not a real soaker, as we can sometimes get here in late August.

    • Roland Derksen says:

      Well, I guess I was wrong: The precipitation began about 1;15 am this morning and was very light at first. It all appeared to be finished by 7am, and my amounts at that hour for the day was a modest 0.36 inches. But after 9am the clouds have really opened up and we’re going to see somewhere close to an inch if my estimate is correct. (which is doubtful!)

  17. W7ENK says:

    Yup, WRF-GFS has shifted the bulk of tomorrow’s moisture even further South, putting the bullseye just North of PDX metro. If that trend continues, (as it has been doing for the last couple of days) then the bullseye could verify right over PDX metro. I think Mark’s assessment of 1/2 inch will be a little low. Could perhaps end up with 2/3-3/4 inch at PDX, with amounts tapering off North/South of here. Who knows, it could swing back the other way before tomorrow, too… we’ll see.

    At any rate, I’m looking forward to another round of free sky water for my garden.

    • PAUL D says:

      Sure hope something hits Hillsboro this time. I’m feeling left out 🙂

    • Joshua Lake Oswego says:

      Looks like things have continued shifting south. Some of us might get very little rain. Barely measurable. Hoping for a decent soaking for the metro area, but looking less promising than it did 8 – 12 hours ago.

  18. Jason Hougak says:

    It’s that time of year, snow in Brooks Range Alaska, I love Faaahlll, looking forward to winter too but let’s take it one season at a time. This summer ranks #1 in my book been perfect!

  19. Kyle says:

    Damn I did it again. I keep forgetting to put the subject in and getting ahead of myself. The only reason we had the rain and snow we did in Feb was due to the changes by the earth ringing like a bell earlier in the winter.

    Soon as it happened the changes began slowly at first but more and more factors were adding up. Even then we got no more then 3 inches best in the big burst.

    Dec 2016 we had 4 and 1/2 inches which lasted almost a week.

    • High Desert Mat says:

      Are you talking about the SSW ( sudden stratospheric warming) we had mid winter?

  20. Kyle says:

    Knowing what I know about the oceans being stagnated I don’t expect this ‘storm’ to really do much more then make it humid and deliver some spitty rain at best before being ripped at it’s guts.

    Most locations will struggle to get a quarter inch at best and y’all watch the totals get cut down on the forecasts as it approaches into real time mode.

    Been there done that.

    The only reason we even had the rain we did was effects from earth ringing like a bell a month or so before which tiny changes can make the weather go cockeyed a bit before recovering to it’s previous default state.

  21. PAUL D says:

    Rain in Hillsboro this time please!

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