Another Unusually Warm & Dry Start to May

6pm Thursday…

Today was a typical “morning clouds then afternoon sun” day west of the Cascades.  We had a relatively strong push of marine air overnight.  That marine layer is thinning now which means less morning cloud cover Friday + more sunshine.  That equals warmer temps; although today’s 66 in Portland only came down to average for May 2nd

Todays Observed Highs OrWa 2017

We have a very nice early May weekend on the way.

Onshore flow weakens dramatically Saturday for a good 6-10 degree jump in temps with little/no morning cloud cover west of the Cascades.  That should push us into the mid 70s.  Expect similar weather Sunday, although several models are bringing a better push of morning clouds & cooler temps that day.  Regardless, a dry May weekend with plenty of sunshine plus temps above average = very nice!

But now things are getting strange again…

During the past two weeks we’ve seen little/no rain for most of us west of the Cascades.

1. That DOES sometimes happen in the springtime for a week or so, but dry spells to two weeks are unusual.

2. Now add in another week of dry weather on the way and that’s VERY unusual.  I just took a look at rain records here in Portland.  This is crazy.  Take the last two weeks of April, then add in these first 9 days of May (assuming little/no rain falls through next Thursday).

3. This year is the driest, followed by…last year!

Three of the five driest late April through early May periods have been in the past few years.  That’s 2019, 2018, & 2015.    We know what happened in those other two years…very warm/hot summers.

We have also seen 6 consecutive dry Mays in Oregon Climate Zone #2 (lower elevations west of Cascades).  That’s after the memorable chilly & wet springs 2010-2012

Capture

This does make me suspect (along with other evidence) that our warming/changing climate has a part in this.  Anecdotally, it seems we are seeing more episodes of upper-level ridging near/over the west coast of North America the past 5-6 years.  Remember last winter we (again) didn’t have any sort of typical stormy westerly flow.  The action (snow & cold) came from a big ridge to our west and cold northerly flow coming out of Canada.  Also it seems we are seeing higher “upper-level heights” in the warm season.  In this case everything would be pushed to the north; Portland’s warm season weather would become more like Roseburg.  Then Roseburg is more like Medford etc…  Again, this is anecdotal and based on what I’ve seen all these years forecasting in our area.

As Pete Ferryman said yesterday, maybe the old saying “summer begins on July 5th” will disappear in time.  We’ll see.

In the short term we have a very stable pattern offshore with an upper-level ridge over a cool upper-low approaching California

ecm_tomorrow

That ridge strengthens and snuggles right up to the Pacific Northwest through the middle of next week.  Notice ensemble averages of the ECMWF, GFS, & GEM models all show the same setup for NEXT WEDNESDAY.  At this point 850mb temps climb above +10 and offshore (easterly flow) may develop

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If so, we’ll see our first 80s of the season the 2nd half of next week.  Here are the forecast numbers I’m using tonight:

Forecast Highs Next 7 Day Meteogram DCA

Our average high temperature now through May 9th is 65-67 degrees so this is well above average.  Not record-setting by any means since they are around 90 this time of year.

What about rain?  Both the GFS and ECMWF ensemble members say we might see some sort of cooler/showery pattern show up around the 13th/14th.  That’s still quite a way off.  Click for a better view

 

Enjoy the weekend!

Chief Meteorologist Mark Nelsen

21 Responses to Another Unusually Warm & Dry Start to May

  1. runrain says:

    Portland looks to have warmer temperatures at the end of next week than Phoenix or Las Vegas if the current forecast holds.

  2. Joshua Lake Oswego says:

    Record high is easily going down on Friday.

  3. Roland Derksen says:

    I’m not expecting (or wanting) a 90F next week- a 70+ reading would be fine. 🙂

  4. Roland Derksen says:

    May 2017 for us was quite wet until the third week of the month, when it became dry and warm. May 2016 was a very dry and warm month, until the last few days when we got a lot of rain.

  5. Garron near the Hillsboro airport says:

    I ‘ve actually lost track. My Birthday is May 8th and in the last 6 or 7 years, it’s been extremely perfect almost all but maybe one of those years? I can’t remember two Birthdays in a row that were this awesome, weatherwise in the entire rest of my 48 years living in Oregon. Temps in the mid 70s and low 80s in the first two weeks of May? Is this the new norm?

    • Tanis Leach says:

      The average first 80 temp is May 10th.

      • Joshua Lake Oswego says:

        Well, we’re going to hit 90 by May 10th. Maybe more than once. We’ll be hotter than Phoenix for at least a couple of days next week.

  6. Kyle says:

    Buuuuuuuuuuuuuuuuuuuuut let’s just tear down all our dams to protect the sucker fish. Make it even harder to produce electricity for electric vehicles and make batteries.

  7. Kyle says:

    When you have a great garbage heap right in the middle of the pacific ocean you think it won’t somehow effect the local climate/ocean currents?

    It doesn’t take rocket science to figure it out but it does take effort to want to remove it. One way is to reduce our use of plastics so more won’t go in.

    Until the 1970s (a little bit in the 60s) we didn’t really have any plastics and things lasted longer regardless of Chinese slave issues.

    Toys were made out of metal and lasted. The only toys that broke were army figures always having their rifles bent which is why they threw it in Toy Story as a throw back to anybody who grew up in that era. The producers of Toy Story said themselves the bag of soldiers always had bent rifles so they threw it in as a inside joke.

  8. Roland Derksen says:

    I’m enjoying this weather as well. It’s not too warm yet- just nice.

  9. Tanis Leach says:

    Is anyone else going to the NW Weather Workshop tomorrow/today (when you read this).

  10. Emmanuel hotya says:

    Perfect dry warm weather should lure in the home buyers and make my house value go up lol on a serious note I wonder what affect the solar minimum has on weather patterns spaceweather.com talks alot about it solar radiation cosmic rays and earth magnetic field affect on weather down here and how all those have been having major changes the last few years

  11. PAUL D says:

    Looks like “unusual” is the new normal 😦

  12. Tanis Leach says:

    2019, 2018, 2015? 2019 isn’t done yet. Heck, early May isn’t done yet, granted it will be dry.

  13. W7ENK says:

    Personally, I’m loving this weather.

    • Evan -- Cedar Mill says:

      Same. I hope it doesnt go back to showery weather until October.

    • Kyle says:

      So does the electric company.

    • Garron near the Hillsboro airport says:

      I ‘ve actually lost track. My Birthday is May 8th and in the last 6 or 7 years, it’s been extremely perfect almost all but maybe one of those years? I can’t remember two Birthdays in a row that were this awesome, weatherwise in the entire rest of my 48 years living in Oregon. Temps in the mid 70s and low 80s in the first two weeks of May? Is this the new norm?

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