The Almost Perfect Setup

Funny how just after I blogged about thunderstorms last Friday, tonight we have the perfect weather pattern for thunderstorms westside.  The only problem is that we probably aren’t warm enough.   Take a look at the map below.   It is the MM5 model from the University of Washington.  It shows the height contours at the 300 mb level (about 34,000′).  Notice the big upper-low off the N. California coast, and the flow around it coming not from the south, but slightly from the southeast.  That’s VERY good for thunderstorms west of the Cascades in the warm season.  As a wave rotates around the low, it encounters air that is "splitting" or diverging "apart" over Western Oregon.  Notice how some of the flow heads back towards the low and another part is headed up towards Washington.  That produces upward motion and can sometimes set off thunderstorms even in the middle of the night.  And with offshore flow at the surface due to the low offshore, we get warm weather down here at sea level too.  I have noticed that just about every single "thunderstorm night" we’ve had here in Portland in my career (since 1991), has been in this pattern.  Southeasterly flow with waves rotating up from the south or  southeast.  So hope for this pattern as we head towards summer!Snapshot_1  Oh, and I can’t figure out how to wrap the text around this image and it’s 11:20pm, so that’s the way it goes…Mark

21 Responses to The Almost Perfect Setup

  1. Justin says:

    I think at least one of us will see a thunderstorm today, or into tonight. The pattern tonight is similar to that of last night. A few cumulunimbus clouds are trying to develop already.

  2. Derek Hodges says:

    Yes I agree Josh. Its been sunny all day and we are at 62. Anybody notice all the lightning in california now sneaking into southern Oregon. I see clouds blowing up over the cascades a little bit. I have been thinking late afternoon we will probably see the storms firing up around here so its good to see some agreement there.

  3. Derek Hodges says:

    Yes I agree Josh. Its been sunny all day and we are at 62. Anybody notice all the lightning in california now sneaking into southern Oregon. I see clouds blowing up over the cascades a little bit. I have been thinking late afternoon we will probably see the storms firing up around here so its good to see some agreement there.

  4. Ryan says:

    It’s about 1 here in Vancouver and our front temp gauge has 66 (exposed to sun) and the rear gauge is (in the shade) is 65 degrees. It’s been clear most the day although some clouds have appeared on the east and west horizons.

  5. i want snow says:

    yeah today is the nicest day so far this year. its about 61.5 here in tigard and its sunny with a few clouds. very nice i have been out in it for a few hours

  6. Justin says:

    I’m impressed by the heating thus far, Portland is 61 at noon, the forecast high was 58. We could warm a few more degrees, enhancing the threat for some convection.

  7. Josh"The Snowman" says:

    Derek,
    Whenever we are in a pattern like this, like Mark’s graphic up there we are ripe for Tstorms here. That south to north flow or even a little southeast to northwest we always get flare ups in the afternoon. Most of them will be in the cascades but I see some “sneaking over” probably later this evening, 6 or 7, perhaps after sunset.

  8. Justin says:

    I wish I could go to Missouri later this week, there’s a good chance of a serious outbreak out there Thursday. Look at the models! Anyways, its not Spring Break here in Washington {I’d imagine it is for you guys?}, but I’m sick so I have all day to watch the clouds. I think Mark’s right, today we need a little more clearing/heating, the good upper lift is all down in California, but its possible we may see a flareup today.

  9. Derek Hodges says:

    The radar will be down until Thursday or Friday, I am thinking unless the news stations have personal radars then today we are going to have to rely on spotters and our own skills today.

  10. Derek Hodges says:

    I think KPTV still has a radar that works but its not very current for us. I guess I could check weather channels. Its probably a good thing there are no clouds yet, we need sunshine all day to cause a few bigger storms to bloom in the late afternoon hours

  11. Derek Hodges says:

    I think KPTV still has a radar that works but its not very current for us. I guess I could check weather channels. Its probably a good thing there are no clouds yet, we need sunshine all day to cause a few bigger storms to bloom in the late afternoon hours

  12. Travis says:

    I looked at the Weather bug and there are some lightning strikes off the coast of California and I think those could work their way up here. I think showers are of high chance. If the showers hit just right then I think we are certain for a little lightning and thunder. I am looking out my window and all I can see is Sunshine. I don’t see many clouds. Despite this I am still thinking it will rain because of models and of course my fellow weather geeks!

  13. i want snow says:

    when do u think that radar will be back up? and are there any other good ones on any other sites?

  14. Derek Hodges says:

    Ok one more thing lol. GFS digs a really big trough in here next monday and tuesday, hopefully another round of storms.

  15. Derek Hodges says:

    Everything seems to be in place but we have to wait and see. The radar has been down so don’t be fooled by that. Is there more than one radar or are we completely blind for storms today? I downloaded the weatherbug so that I can get semi-current lightning strikes, I think that is the best free lightning thing I have run across.

  16. Derek Hodges says:

    What do you mean by the lift is there, is there a special way to know that or do we just know that from models? Anyway sunny here. It woke me up by shining in my eyes so I guess thats a good sign lol

  17. Josh"The Snowman" says:

    Looking really good so far this morning. It’s only 9 am and the lift is there. If we get some sunbreaks this afternoon, watch out!

  18. Travis says:

    I am hoping for numerous storms because its about time something interesting happened. I think chances are moderately high.

  19. Travis says:

    I am hoping for numerous storms because its about time something interesting happened. I think chances are moderately high.

  20. Derek Hodges says:

    What do you think is our percentage chance of a t-storm tomorrow?

  21. Derek Hodges says:

    Well you never know. If the set up is so good maybe with a little afternoon heating some storms will pop up around the late afternoon hour. Thats what I am hoping for anyway. If were lucky it could be good. Is this what causes our occational severe storm now and again in the summer?

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