Enjoy the Weekend; A Wet & Chilly Week Ahead

Hard to believe, but our 4th weekend of April appears either dry and mild or mainly dry and mild.  Tonight’s warm front, spreading light rain into the northwest part of Oregon, will fizzle and dissipated right over the top of us later tonight and into Saturday morning.  That leaves us with a gray start Saturday, but increasing afternoon sunshine.  Sunday will just be partly cloudy or mostly sunny.  Both days our RPM is trying to generate weak convective showers over the Coast Range and Cascades in the light westerly upper-level flow.  Thus the “mainly dry” wording.  Most likely we have a dry weekend ahead.

Then, it’s on to May!  Unfortunately, the first week of May looks to be unusually wet and chilly.  Early on in the week we get “zonal” flow which is our usual westerly jet stream bringing in cool and wet systems.  Then the latter half of the week (and probably next weekend) a colder upper-level trough digs down over us.  Take a look at the 00z ECMWF’s 500mb anomaly forecast for the 7 day period starting next Monday-Tuesday:

Note the large negative anomaly over the West Coast, western Canada, and Alaska.  In fact the next 7-10 days sure looks like the March weather pattern doesn’t it?  Nice that the heat returns to the eastern USA too.  A peek at the 12z ECMWF 850mb ensemble chart shows below average temps (around 5,000′ elevation) from Monday to next Sunday, the lots of variation after that time.

The 12z GFS is similar, although it holds onto the cooler than average temps a good 1-2 days longer.  Brrr!  

The screaming message is that next week will feature lots of cancelled spring sports practices and games, along with chilly temps and mountain snow down to 3,000′ or even lower at times.  Hopefully you didn’t plant your tomatoes or corn yet!  I just planted tomatoes in my greenhouse I built last Fall.  In there, even on days like today, it gets up to around 80.  A little bit of climate change going on at the Nelsens.

So once again…enjoy the mild and dry weekend!

Chief Meteorologist Mark Nelsen

23 Responses to Enjoy the Weekend; A Wet & Chilly Week Ahead

  1. bgb41 says:

    4/28/2012 Oregon (All) Temperature Summary

    High:73 at CW3932 Central P(1290 ft) & CW5474 Grants Pa(915 ft)
    Low: 51 at Rufus(185 ft)

    High:29 at HOWARD Mt Howard(8150 ft)
    Low: 20 at MT. HOWARD (7910 ft ) & ANEROID LAKE #2 (7300 ft )

    Largest Diurnal Change: 37 degrees
    Lorella (64/27 ) (4160 ft )

  2. Took a short trip to Palouse Falls in Washington today. River still running pretty brown.

  3. Greg C. says:

    I am not to worried about impending wet weather that is coming. I am pretty much stuck recovering from open heart surgery here until about June sometime. Probably maybe more like late June than the early part also. I guess I will have a more clear idea on that on May 3rd when I see the surgeon for a follow up. It does seem like things are slowly getting better though.

  4. bgb41 says:

    4/27/2012 Oregon (All) Temperature Summary

    High:64 at PROVOLT SEED ORC(1180 ft) & Castle(283 ft)
    Low: 49 at Union Jct(2700 ft) & CW8449 Charlesto(322 ft)

    High:28 at HOWARD Mt Howard(8150 ft)
    Low: 16 at HOWARD Mt Howard (8150 ft )

    Largest Diurnal Change: 30 degrees
    CW8927 Young Lif (63/33 ) (1631 ft )

    Heaviest Rainfall:
    0.82″ at BOULDER CREEK(3570ft)
    0.67″ at RED BOX(3250ft)
    0.61″ at MT. WILSON(3780ft)

  5. boydo3 N Albany says:

    Both ensembles look warmer after next week. We can only hope.
    La Nina or El Nino?…more likely we slide into an El Nino. But given the last two La Ninas, who really cares? We get what we get.

  6. bgb41 says:

    Well this is usually what historically happens after a record heat wave in spring. At least we got a nice kick-start to spring this year. 2010 and 2011 were bad.

  7. *BoringOregon* says:

    Well looks like I’m going to start my, atlantic Giant pumpkins in doors this yr! Looks like last weekend well only happen once lol.

  8. karlbonner1982 says:

    I think I’m gonna start the corn now because even in a chilly pattern, The Dalles is a good 5 degrees F warmer than Portland is in early May. And corn isn’t quite as fussy about cool weather as tomatoes are.

  9. Jbpdx says:

    Forget May predictions. I’m trying to decide when they’re going to announce that la Niña is continuing—-yet again. Or when they will admit that it is the new normal. Or even better, admit what’s causing it.

    • Mark Nelsen says:

      Right now models are saying either neutral or El Nino for next winter. It’s extremely rare to have 3 La Nina winters in a row…but it HAS happened. I saw a talk in early March in Seattle about this. The speaker said models generally don’t have a good idea of the ENSO signal until AFTER May each year. Last year is a good example. Looked like it would go neutral, but then it slipped right back into La Nina.

    • Jbpdx says:

      Sticking around for the May Day “festivities” then I’m gittin’ in the car and heading to Sacramento and points south where I can enjoy the sun! Gonna check out those real estate bargains in Las Vegas….

    • karlbonner1982 says:

      May Day festivities? Are you referring to 99%er stuff or a May Faire?

  10. bgb41 says:


    What will May 2012 be like? I am running yet another new contest. See how well you can guess temperatures and precipitation totals/frequencies for this upcoming month. Click the below link to submit your guesses. Entries close on May 4th.


  11. Mr Data says:

    Any chance of a late frost down to the valley?

  12. Larry says:

    Wow, mountain snow, sure would like to see the end of that so we can get back into hiking.

  13. Sandi (Wilsonville) says:

    Tomatoes are planted, but your post reminded me to put a wrap around the tomato cages to mimic a greenhouse. Thank you for the new post. 🙂

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