Early May Weather: Drier, Wetter, Then Drier

6pm Monday…

The past few days have seen classic mid spring weather.  We seen times of cold downpours including hail and a rumble of thunder, then 10 minutes later the strong sunshine is blazing down and rooftops steam.  This is exactly what we would expect to see in May; typically interspersed with warm spells (like last week).

The weather pattern itself continues to be quite slow as we head into the next 7 days.  The general plan is for dry or mainly dry weather the next two days (TUES/WED), then showers for 3 days following (THUR-SAT) as wet westerly flow pushes through the Pacific Northwest.  Beyond that, we’re headed for another warm week similar to last week.

Here are some charts/maps to back that up.  First, the 12z ECMWF meteogram, which tends to show maximum temperatures a few degrees too low:


Note the 3 day wet period as I mentioned above.  Here is the 12z ensemble chart from the same model:


I see good agreement among all 51 ensembles for the cooldown with the rain the latter part of this week.  Snow will get quite close to the passes again Friday-Saturday.  The operational run is then right in the “middle of the pack” with respect to the warmup early next week.  It’s peaking in the lower teens the middle of next week.  You can see a few members have a stronger ridge with 850mb temps up above +15 like last week.  But a few weaker/cooler too.

Here’s the 12z GFS ensemble chart:


Looks similar; colder than normal Friday-Saturday and then quick warming.  I took rain out of Monday’s forecast based on the dry ECMWF and this chart.  Note how the operational run (which shows rain Monday) is the lowest of all members Monday morning?  That’s the dip just before the “13MAY”.  It is dragging a cool upper level trough right over us.  So a good move to ignore the GFS for the last day of the 7 day forecast and go with the ECMWF based on this.  And now the 18z GFS chart is a bit more reasonable:

tseries_850t_000-384_Portland (1)

The low Monday temp is gone here as it has come around to the dry ECMWF solution.

So there you go, a real mix of cool and warm weather coming up with no long dry or wet periods.  Some pretty decent May weather!  I would say it’s been a decent spring too.  March was obviously quite wet, but April saw near normal rainfall.


Temperatures this spring have actually been slightly above average; so it appears this will be our 2nd consecutive spring without any long, drawn out cool and wet period.

Chief Meteorologist Mark Nelsen






41 Responses to Early May Weather: Drier, Wetter, Then Drier

  1. schmit44 says:

    5/8/2014 Oregon (All) Temperature Summary

    High:74 at HEPP( 311 ft) & DW1597 Troy(1612 ft)
    Low: 53 at HEPP(311 ft) & DW1597 Troy(1612 ft) & John Day River B(305 ft) & RUFUS(185 ft)

    High:37 at Rim(7050 ft) & ALAKES Haines(7979 ft)
    Low: 19 at ANEROID LAKE #2 (7300 ft )

    Largest Diurnal Change: 42 degrees
    HEREFORD (64/22 ) (3599 ft )

    Heaviest Rainfall:
    2.34″ at EW4856 Brookings(1365ft)
    2.00″ at NORTH FORK(3120ft)
    1.91″ at HEBOWX Mt. Hebo(3160ft)
    1.90″ at LITTLE MEADOWS(4000ft)
    1.79″ at CHARLOTTE RIDGE(1220ft)
    1.74″ at YELLOWSTONE MTN.(3080ft)
    1.68″ at QUAIL PRAIRIE LO(3183ft)
    1.57″ at FLYNN PRAIRIE(1543ft)

  2. W7ENK says:

    0.58″ of rain today, over half of that fell between 6 and 7 pm.

  3. Tyler Mode in Battle Ground says:

    0.67″ so far today in Battle Ground and still pouring rain

  4. High Desert Mat says:

    Hopefully the warm and dry weather sticks around for longer than next week, as I’m heading for the season opener in Woodburn for the dragstrip on the weekend of the 18th, my bday.

  5. Jesse-Stevenson says:

    What an insanely warm new 7-day, and without any model support even. Someone’s got a warm biased hankering for summer.

  6. schmit44 says:

    5/7/2014 Oregon (All) Temperature Summary

    High:74 at JOHN DAY RIVER A( 400 ft) & MERLIN SEED ORCH(1144 ft) & John Day River B(305 ft) & ECHO(683 ft)
    Low: 53 at HEPP(311 ft)

    High:33 at HOWARD Mt Howard(8150 ft)
    Low: 14 at DIMLKE (4726 ft )

    Largest Diurnal Change: 44 degrees
    CABIN LAKE (64/20 ) (4560 ft )

    Heaviest Rainfall:
    0.40″ at ANEROID LAKE #2(7300ft)
    0.30″ at MT. HOWARD(7910ft)
    0.22″ at Upper Wildhorse(3581ft)
    0.19″ at HOWARD Mt Howard(8150ft)
    0.16″ at BLACK MTN RIDGE(4965ft)

  7. Boydo3 N. Albany says:

    12Z Euro is really amplifying the ridge next week.

  8. WEATHERDAN says:

    It looks like 2010 and 2011 were aberrations with their cold and wet Springs. 2012 was at least average if not a little above. And last Spring was quite warm. I have noticed much less doom and gloom predictions for this Summer then in the past few years. With our average highs now in the mid 60,s our chances of getting a high of 55 or less looks pretty slim from here on out. Today is completely sunny and probably headed for about 70 degrees. Exactly 3 months ago today Salem had a high of 27 and 14 inches of snow on the ground. This weekend our sunset creeps past 8:30 PM. Our sunrise is getting close to 6:00 AM. Peace.

    • Karl Bonner says:

      Just watch…PDX is gonna get a 7-10 day stretch in June where they never get above 70 degrees. Guaranteed after all this heat! ;P

  9. Ted Berry says:

    Light frost here this morning down around 35 degrees, another week before we are out of frost/freeze danger in the Barton area.

  10. Had I known it was going to be 35 degrees this morning I just may have closed the windows in the house haha

    I didn’t know it was going to get ‘quite’ that cool!

  11. Muxpux (Castle Rock 175') says:

    Is there a reason there seem
    To be lots of May bdays or is it because I’m a may baby I notice it more. Thursday for me. Not looking forward to working in the rain. Spare me weather gods!!

  12. schmit44 says:

    5/6/2014 Oregon (All) Temperature Summary

    High:72 at JUNIPR( 359 ft)
    Low: 53 at John Day River B(305 ft) & RUFUS(185 ft) & Celilo, East of(225 ft) & DW6006 Troutdale(262 ft) & WYETH(102 ft) & DW6132 Portland(272 ft)

    High:30 at HOWARD Mt Howard(8150 ft)
    Low: 15 at KIRK (4519 ft )

    Largest Diurnal Change: 37 degrees
    CABIN LAKE (57/20 ) (4560 ft )
    Sand Creek (US 9 (54/17) (4525 ft)
    KIRK (52/15) (4519 ft)

    Heaviest Rainfall:
    0.48″ at K7ZQU-7 Santiam(4790ft)

  13. Dave in SW PDX (235') says:

    Happy 45th Birthday, Mark – I hope cake & candles were part of your schedule at some point today. Sorry to see you’re working on your birthday, though.

  14. BoringOregon says:

    Happy Birthday Mark! Well…. I hope we can get on with the Warm weather all ready :).

  15. Karl Bonner says:

    Happy Birthday Mark!!!!!

    Instead of another brief hot spell, let’s have a longer period of medium-warm weather this time! Like 5-7 dry days in the 70s…

  16. pappoose in scappoose says:


    • Garron near Washington Square says:

      Thanks Pappoose, glad the lettering on your card is in BOLD PRINT too. Wish the mind went before the sight and hearing, what, who said that? Now, what was I talking about? Oh yeah, anyone seen my car keys? I set them right next to my reading glasses.

    • High Desert Mat says:

      Thanks pappoose!!

  17. High Desert Mat says:

    Happy Birthday Mark, seems there’s lots of May bdays. Mines the 18th, I was turning 4 when Mt. St. Helens blew.

  18. PaulO says:

    Happy 29th Mark!

  19. lilfoot123 says:

    Happy Birthday Mark

  20. W7ENK says:

    Happy Birthday, Mark! 🙂

  21. Garron near Washington Square says:

    Happy Birthday Mark! I hope your birthday wish comes true. Funny, i didn’t realize we’re just two days apart, mines the 8th.

  22. schmit44 says:

    5/5/2014 Oregon (All) Temperature Summary

    High:75 at BARNHT( 894 ft)
    Low: 54 at W7OBH Canby(164 ft)

    High:32 at Rim(7050 ft)
    Low: 22 at MT. HOWARD (7910 ft ) & Mount Hood Meado (6601 ft )

    Largest Diurnal Change: 31 degrees
    BARNHT (75/44 ) (894 ft )

    Heaviest Rainfall:
    0.57″ at RED BOX(3250ft)
    0.54″ at BOULDER CREEK(3570ft)
    0.53″ at PEBBLE(3450ft)
    0.52″ at TOKETEE(3360ft)
    0.52″ at SOUTH FORK(2257ft)

  23. schmit44 says:

    May 6: Tomorrow is Mark Nelsen’s birthday. Happy Birthday!!!

  24. Sifton says:

    Good!! Gettin tired of rain though, remember everyone freaking out at the end of last year about it being dry?? Lol…….

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