Done With April; On to May

By one measure this Spring is doing far better than last year.  Check out the number of 60 degree days so far this year:

Compared to last year, and the chilly spring of 2008, it’s a decent improvement.  Looks like April temperatures ran quite close to average across the Pacific Northwest, here’s a graph showing temperature anomaly over the past 4 weeks across the west from Western Region Climate Center…the rest of the country has been warmer than average too, although not as extreme as March:

Well, the first week of May, or at least the first 6 days, will be quite cool.  This has been a well forecast cool and wet spell (see previous blog postings).  Cool westerly flow in the upper atmosphere turns more into a cool upper level trough as we get to the end of the week.  Then that trough “closes off” into a chilly upper level low and takes it’s time getting out of here this weekend.  As a result, this upcoming weekend will probably be the coolest we’ve seen in a month.  850mb temps Saturday morning bottom out around -4, impressive for May. 

The surface low and associated moisture may give us quite a soaking Thursday; that appears to be the wettest day of the week.

Models are in pretty good agreement on upper level heights rising Sunday and into next week for a return to normal or above average temps.  Here is the 00z GFS ensemble chart:

Interesting to note the last few weeks that as we move into the warm season, even these 5,000′ temps are affected by the strong diurnal heating.  You don’t see that October-March. 

And here’s the 12z ECMWF, showing above average 850mb temps beginning next Monday, at least in the mean:

Chief Meteorologist Mark Nelsen

26 Responses to Done With April; On to May

  1. Hal in Aims says:

    yep…the little yellow mark just appeared……

    • W7ENK says:

      We will have to wait for confirmation from an authoritative source before we can rule out that this is not another error… There seem to be a lot of false positives on the lightning detection map as of late.

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      In the below comment, Hal did report flash, crack, and shake… I think thats positive evidence.

    • W7ENK says:

      It was a joke, Tim. Laugh a little, it’s good for the soul! 😉

    • boydo3 N Albany says:

      flash, crack and shake, I think I remember that song…

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      When I first posted I guess I didn’t see that Erik!

      “Flash, crack and shake!!!” LOL

  2. Hal in Aims says:

    holy s………just had simultaneous flash……..crack……still shaking….had to have hit very close….

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

    Heavy shower with BB-size hail moved thru the Tigard area @ approx 4:10 pm.

    • weathercrazy82 says:

      At first I read that as baseball not BB…

      Just got done raining and hailing here the temp is down to 45 now.

    • snodaze says:

      haha… I too had ‘baseball’ run through my head at first…

    • Dave in SW PDX (235') says:

      Funny, that didn’t even cross my mind at the time. I probably should have said “a little smaller than pea-sized” hail.

    • Emily Waldman says:

      We had heavy rain & hail in Longview, WA around 2:30p

  4. Kassie97222 says:

    Dark cloud cover just passed and was pretty breezy, now it is raining quite a bit…

  5. boydo3 N Albany says:

    I really like the long range trend compared to the last couple springs. We have a backpacking fishing trip planned around Mother’s Day down into the Deschutes and Squaw Creek canyons. We do it every year and it seems like the last several years have been cool and damp compared to our trips in the 90s.

    • Sandman, Aloha 300' says:

      I know I am excited for my bees too. The previous 2 springs have been very hard on the bees. Maybe we get to have some spring honey this year.

    • boydo3 N Albany says:

      Seems like bees got a late start again this year. But the last week I’m seeing some in out apple trees. bzzzz…..

  6. muxpux (Longview) says:

    having a nice hail shower here right now…

  7. weathercrazy82 says:

    I was surprised Vancouver and PDX had less that 0.05″ yesterday. I had 0.65″…I know I normally get more, but that is a very large difference.

    • W7ENK says:

      Right?!? I had 0.56″ yesterday. I was very surprised to hear such low amounts all around.

    • bgb41 says:

      Very common with a strong post frontal low level jet to get maximum shadowing around PDX. I got hammered with heavy showers too a good part of the day yesterday. Notoriously in the spring I double the rainfall in PDX due to upsloping.

  8. Jbpdx says:

    Hillsboro–April 2012

    16 days below average temps
    2 days ave
    12 days above ave

    The bad stat: days with rain = 21

  9. W7ENK says:

    YAY for MAY!!! 🙂

    • W7ENK says:

      So, does this mean I’m going to be freezing my @r$e off at 4,000 ft between Dufur and Mt. Hood this weekend?? There’s still quite a bit of snowcover above that elevation all throughout the state. I came upon some roads last weekend that were still buried under ~2 ft of snow!

  10. stormblown says:

    Mark, Will the passes over the cascades be clear on Thursday?

  11. bgb41 says:

    4/30/2012 Oregon (All) Temperature Summary

    High:72 at LAKE OWHEE AND O(2400 ft)
    Low: 52 at Rye Valley(I-84(2230 ft) & Arlington Airpor(890 ft)

    High:34 at Timberline Lodge(7001 ft)
    Low: 21 at Timberline Lodge (7001 ft )

    Largest Diurnal Change: 30 degrees
    FISH FIN RIM (67/37 ) (4907 ft )

    Heaviest Rainfall:
    1.83″ at YELLOWSTONE MTN.(3080ft)

  12. Longview - 400 ft says:

    Looking forward to warm temps again next Monday!!!

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