Warm April Weather

SnapshotSnapshot2Obviously today was not the warm April weather I refer to in the title.  Clouds were a bit thicker and showers a bit more widespread than I was expecting this afternoon. 
00z models are in and they look quite similar to earlier model forecasts for the next few days.  We have one more day of cloud cover and light showers tomorrow.  Then a developing strong ridge of high pressure pushes clouds and rainfall to the north for Thursday and Friday.  850mb temps on GFS, WRF, and MM5 reach the +11 or +12 mark Friday.  At the same time easterly offshore flow returns from Thursday morning through Friday midday, then the wind turns calm Friday afternoon.  This setup has given us "surprisingly" high temperatures many times in my forecasting career here in Portland (which would be my entire career).  The Mark Nelsen "magic chart" I use for warm season forecasting gives us a high of 75 with no easterly wind, as high as 81 with perfect easterly flow conditions.  If maps are correct and nothing changes, we could hit 80 at PDX on Friday.
Beyond that, another interesting change in the GFS this evening (but not in WRF).  It shows the Saturday system approaching the coast becoming more cutoff and sending southeasterly flow up over us during the day.  That’s a thunderstorm pattern in the Northwest from April to September.  In the long range, cooler and wetter weather is back beginning possibly as early as Easter Sunday, but more likely Monday…Mark

19 Responses to Warm April Weather

  1. Boring Larry says:

    From Rockey’s Afternoon discussion:
    Who am i to argue with the NWS????

  2. Sean (Lebanon, Indiana) says:

    Gregg – Yeah, its 29 and been snowing on and off (had a little bit of sticking).. It’s really hard to kind of fathom.. Had to BBQ and new patio set out, now it’s back to into mode for a few days..

  3. Gregg-Troutdale says:

    What a nice afternoon, finally into the 60’s here, and looking forward to the 70’s the next couple of days. Very light E wind now. Sean, I was really surprised to see how fast your temp dropped last night Sean. And to see them continue to fall throughout the daytime today.

  4. garron near washington square says:

    a balmy 65 here now, can’t wait for the warm up!!!! go summer, forget spring!!!

  5. Sean (Lebanon, Indiana) says:

    Maybe throw in an EF5 tornado to complete the thunderstorm?

  6. Derek-West Gresham says:

    As long as it hits my house on the way to you. šŸ™‚

  7. Andrew---Ellensburg, Wa and Portrland, Or says:

    haha, thats true, something will happen. Something always happens on my drives down to Portland haha. From heavy ice accumulations to snow on the road the entire way, something always must happen. Maybe a severe thunderstorm will pop up out of nowhere dumping dump truck sized hail, who knows (that would be very scary by the way).

  8. Derek-West Gresham says:

    Some mountain will explode and release a pyroclastic flow Andrew. Its never easy for you! 80 would not surprise me, thunderstorms will seem possible.

  9. Andrew---Ellensburg, Wa and Portrland, Or says:

    Starting to look like a hot day here in ellensburg, wa this friday. I think we could easily hit mid-upper 70’s. Right now the NOAA is calling for 73 and weather.com is calling for 77 and the local station here is calling for 76. Will be a nice day for driving down to portland, i should not run into any weather related problems.

  10. AtmosphericWrath -Southeast Portland- says:

    TTD-DLS gradient increased to -2.7mb
    I’m wondering now if we lose the E wind today.

  11. Derek-West Gresham says:

    6z models keep that feature around but drag it south instead so that it shows us getting nothing. It will be a few days before we know.

  12. AtmosphericWrath -Southeast Portland- says:

    Wow that’s insane Sean.
    No late April Fools joke either.
    48.4F E wind 5-10mph
    TTD-DLS gradient down slightly to -2.1mb

  13. Sean (Lebanon, Indiana) says:

    Talk about some crazy weather.. At 2pm yesterday it was 76F, at 9am this morning it’s 32F with light snow.

  14. AtmosphericWrath -Southeast Portland- says:

    Thanks for the update Mark. Hoping the cutoff low continues to show in model runs today.
    50.0F with E wind 15-20mph.
    As I was possibly expecting last night the E wind never shut off last night, at least not at my house.
    In fact about 3-4am had some 30+mph gusts.
    TTD-DLS gradient -2.8mb so offshore flow isn’t giving up just yet.

  15. Ben says:

    Yeah, let’s hope for 80, that would be great!!

  16. Austin-Ridgefield says:

    Thanks Mark for the update. I sure do hope we get some thunderstorms saturday I have been waiting for them. Also go seattle there 2-0 know tied for first maybe good year.

  17. Andrew---Ellensburg, Wa and Portrland, Or says:

    Thanks for the update Mark!

  18. Gregg-Troutdale says:

    Thanks Mark!! Looking forward to the warmer weather, whenever it decides to show up.

  19. offroadjosh-aloha says:

    Thanks Mark!!

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