Back to the Sunshine

Snapshot  I'm trying to stay ahead of the ball tonight (not really a reference to the OSU game, although I suppose it's timely).  The weather forecast is somewhat simple.  Last night's cold front has moved well off to the east, leaving us in weakening onshore flow.  When I showed up at work around 1pm, you could clearly see the surface low off of Vancouver Island.  That has now dissipated and moved inland.  Surface high pressure builds inland tonight, giving us weak offshore flow tomorrow.  That plus warmer air in the atmosphere overhead should give us about 10 degrees warming.

An upper-level trough passing by to the north Saturday keeps us from warming more than a degree or two.

All models are now in agreement with a strong upper-level ridge rapidly building directly overhead on Sunday.  This is partly due to deepening storms in the Eastern Pacific.  500mb heights go up to 586-588dm by Sunday evening.  That's a very warm atmosphere, especially for the last few days of September.  And it'll be centered directly overhead on Sunday and early Monday.  This time of the year it'll be easy to get easterly wind with this setup.  In fact Sunday and/or Monday we may see 80 degree temps at the Coast assuming the easterly flow makes it that far.  12z models had shown the thermal trough making it out to the beaches, and now I see the 00z NAM has easterly flow stronger near the surface than up at 850mb…that looks more like Fall than Summer.  It goes without saying that we're going to have one (last?) "heat wave" to wrap up this month.  That's why I put Monday's high up to 90 degrees.  850mb temps of +22 and easterly wind to PDX should do it.

The other piece of agreement in the models is in the long range.  They keep pushing the arrival of some wetter westerly flow farther into the future.  12z and 18z models all showed rain holding off until after midweek.  The combination of southerly upper level flow and/or easterly surface flow is going to keep us warm through the first day or so of October…Mark Nelsen

13 Responses to Back to the Sunshine

  1. HIO Phil (Punxsutawney) says:

    Grandma’s cookies, I don’t have any memories of that, (and no it’s not because of what I may have done in college).
    That was in Florida and Kentuncky in the summer and I was haveing too much fun watching the t-storms, or at the beach, or catching crawfish and cutting them up to fish for bass, to remember the cookies.
    Currently 59.4, fairly warm still.

  2. luvry says:

    Very good point Jesse. Inversions this time of year get very stubborn with the cooler/longer nights. It’ll be interesting to see how this plays out.

  3. luvry says:

    Jesse, it will depend on the east wind I believe. +22 at 850 could easily hit 90 if there is a easterly flow at PDX.
    i’ll go a little warmer than you…88 is my best guess.

  4. Luvry (Tanasbourne) says:

    Exactly Ryan, we would only near the 90 mark for a bit and then the temps will drop off quickly, especially on the westside, assuming the eastside will be seeing some easterly flow.

  5. Mark Nelsen says:

    You people are distracting me from my work!…and who’s “Cucky”?

  6. Mark Nelsen says:

    Looks like southerly with the 850mb surface high off to the SE. Appears to be around +18 deg C.

  7. Chuckyd81 says:

    Should read “say” instead of “saw”.

  8. Atmospheric Wrath -Far S.E. Portland- says:

    00z NAM cross section model shows winds surfacing all night and stronger than aloft..

    That could easily keep areas 65+
    I wonder what the 12z NAM cross section shows..

  9. Andrew Johnson (Silverton) says:

    Its 50 degrees and quite foggy right now. Making me wonder if we’ll hit the predicted 75 if this fog hangs on for a few more hours. I would seriously doubt we hit 90 on monday, but you never know. In other news the first decent snowfall of the year is getting going in Northern Alaska.

  10. HIO Phil (Punxsutawney) says:

    Will the Beavers win Larry? Does it rain in Cherryville? Ok it wasn’t that certain, but way to go Beavs!
    Ok, back to weather.
    West Side Weather Report: Cool this morning with patches of ground fog. Temps in low 40’s. A sliver of the moon in the eastern sky.
    Today sunset in Portland is 6:59pm and won’t be back after 7:00pm until next March with the onset of daylight savings time.
    Anthony, The 06z spins up a couple of good storms, one on the 3rd, and another around the 9th.

  11. TriforceofInvisibility says:

    Part 2: Septly’s tend to run much drier then average.

  12. Atmospheric Wrath -Far S.E. Portland- says:

    #1 USC 21
    Oh what an awesome game College Football is!
    Mark, I like your forecast…. Would be nice to sneak in some convection too. Also I am thinking the E winds will persist overnight east of I-205 keeping those areas in the upper 60’s at least…

  13. Derick says:

    Just wondering if anyone knows what kind of fall/winter we’re supposed to have???

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