A Week of Showers Ahead and First Look at Memorial Day Weekend

6:45pm Thursday…

Yesterday we saw vigorous showers move through the east metro area around this time, dumping up to 3/4″ of rain.  Today the heavy showers are east of the Cascades with lighter showers west of the mountains.  Models are shoving lots of moisture into far eastern Oregon tonight and Friday; NWS Pendleton has a flood watch out for that area

Mark Flooding California

The reason for all that rain is an upper level low moving into Northern California this evening.  I expect two more of these disturbances to take a similar track over the next week.  They show up nicely on the ECMWF model’s ensemble forecast.  First, Sunday morning you see that cold low in the same position as tonight’s low

ecm_sun

Then a second low on Tuesday as the first low spread severe thunderstorms and tornadoes into the Great Plains…

ecm_tues

Both of these are forecast to drop a little farther south than what models were showing earlier in the week.  That means most of the rain the next seven days heads into California and we see lighter showers across NW Oregon and SW Washington.

This setup of lows moving by just to the south is a forecast nightmare as well.  Little waves of showers spin north; each model run is slightly different on placement and timing.  It’s safe to say we’ll see light showers at times, but there could be large windows of dry weather some days in the next week.  Right now it appears the first 3/4 of Saturday will be dry and much of Sunday could be as well.

Check out the ECMWF rain forecast for California…FAR more than anything they typically see in late May

ECMWF Precipitation Accumulation

Now the big question…

How long will this cool/wet pattern continue?

There are strong hints that we’ll return to a drier/warmer pattern as we head toward/into the Memorial Day Weekend.  No, I’m not saying we have a sunny/hot/warm/dry holiday weekend on the way (for now).  And yes, it’s 9 days away, but we can see general weather patterns that far out.

For several days most long range model solutions are showing the cool upper-level troughing sinking farther south into the Desert Southwest and high pressure (ridging) developing once again just to our west.  Similar to what happened in late April and early May.  Notice the ensemble forecasts from the GEM, GFS, & ECMWF for Saturday the 25th all look the same

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This would say mainly (or all) dry weather with average to above-average temps.  We’ll see how that plays out.

You can see the drastic change from week #1 to week #2 in last night’s 45 day ECMWF run.  This is surface temperature anomaly.  First from this coming Sunday to the Sunday of Memorial Day Weekend.   Look at that cold anomaly over Nevada/Utah, 15 degrees below average next week…Brrr!

sfcta_week1_bg_NA

Then the following week; cold moves farther east/south.  The west coast of North America from Oregon to Alaska would be very warm

sfcta_week2_bg_NA

So there you go.

Cool and showery this next week but not too much rain.

Enjoy your weekend!  Chief Meteorologist Mark Nelsen

 

21 Responses to A Week of Showers Ahead and First Look at Memorial Day Weekend

  1. JohnD says:

    A full month away from solstice–but even in our PDX latitude, on a mostly cloudy evening, still plenty of daylight remaining at 8:40 p.m.
    Amazes me every year–especially when solstice finally does roll around and it is even more dramatic!

  2. Jakeos7 says:

    It just started pouring in OC. The radar is showing heavy rains about to move through the metro area.

  3. JohnD says:

    Was in Albany this afternoon visiting friends. Great T’storm event there for sure. Driving home back to PDX hvy rain the entire time plus more lightening now and them. Shut off just south of PDX.

  4. JERAT416 says:

    I was in Beaverton between 5 and 6 when it came through. Got some gusty wind and hard sideways rain, and it cooled down pretty good. No thunder or lightning though

  5. W7ENK says:

    Looks like the whole thing shifted West and missed me here in Milwaukie. No thunder, not even any rain yet… ☹️

    • Joshua Lake Oswego says:

      West and south of Portland got hooked up. A few minutes of rain and wind here and that’s it.

      • W7ENK says:

        Didn’t even get the wind on this side of the river. Light sprinkles off and on for the last 90 mins is all. Temp dropped 20 degrees though, so there’s that.

      • Doug in Lake Oswego says:

        Same thing in Lake Grove. Less than a mile down Boone’s Ferry, just before I-5, a massive drenching thunderstorm, so Tualatin apparently got a huge soaking. Here in Lake Grove, nothing. The frustration continues.

  6. W7ENK says:

    Portland radar just took a crap, so we should be getting some decent thunderstorms.

  7. Andy says:

    Wow…what a storm here in Albany.

  8. W7ENK says:

    INCOMING!!!

    Lightning strike map, last 2 hours.

    Moving North.

    • Kyle says:

      Looks like Britain and Ireland moved north a bit. The big blob is Britain and the little one is Ireland with it’s south half cut off. Cork area and SW Ireland.

  9. Andy says:

    Hearing rumbles of thunder south of Albany. Looks like Eugene is having some fun.

  10. Joshua Lake Oswego says:

    Tomorrow afternoon/evening/night is actually looking pretty juicy. Wouldn’t be surprised to see widespread accumulations of .50’’.

  11. I keep watching that red blob over the Pole! That seems worryingly ominous. Is it becoming the new normal?

  12. Roland Derksen says:

    The warm weather will be back soon enough- right now i don’t mind the cloudy coolish conditions.

  13. W7ENK says:

    Just under a half inch at my place over the last 3 days. I’d say that’s a decent amount. My garden seems happy, and I love the way everything smells fresh!

  14. Doug in Lake Oswego says:

    +1 on Joshua’s comment. Forecast after forecast for a “soaking” that inevitably produces some widely scattered wimpy showery thing with maybe 10 minutes here and there of actual rain. My sister in Sacramento phones and relates the coming of the Second Deluge in NorCal this past week vs our maybe half an inch total, or whatever. No, it’s not whining, rather a recognition of an ongoing frustrating reality that dumps the big rain everywhere but here. Repeatedly. Our landscape maintenance guy, who has been doing this for 25 years has told me several times that the weather here is changing to more of a typical NorCal pattern. Sure seems that way over the past 4 or 5 years.

    I keep hoping. But no longer expecting.

    Doug In Lake Oswego

  15. PAUL D says:

    I’m in Indiana and saw a really awesome thunder and lightning display like we never see in the Portland area!! And if that wasn’t enough, then it hailed for 15 minutes and the hail was up to an inch in diameter!! WOW!!

  16. JERAT416 says:

    It hasn’t been a bad week at all. Mother nature is making up for the heat way ahead of season.

  17. Joshua Lake Oswego says:

    I was going to post about yet another series of under-performing rain events, but didn’t want to be called a whiner. It is what it is. No bias. Disappointment after disappointment. This “wet” week will end up being a below average May week for precipitation. On the plus side, it ain’t freakin’ 90.

    And… first!

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