Those Darn Marine Clouds

They are back!  The most hated part of forecasting in the warm season…those marine clouds.   They moved inland nicely overnight as expected, but like an unwanted house guest they never completely dissipated over and north of the Portland Metro Area. 

You may remember last night I was afraid the push would be too weak again, so I raised the forecast high from 61 to 63.  Instead we only hit 59.  This happens quite a bit in the summer.  The thickness of the marine layer is always hard to predict.  Not exactly a life-threatening forecast problem, but still a problem here west of the Cascades.

But there is always tomorrow right?  Rising 500mb heights are the story through Friday as a strong ridge of high pressure builds over the West Coast.  Higher heights tend to "squash" the marine layer as subsidence increases.  For this reason, the clouds tomorrow and Friday should dissipate much faster.  At least that’s the plan.  No offshore flow Friday means mid 70’s will be hard to do.  Then another wave passes by Saturday, giving us a major push again.

00z models stay with the return to stronger ridging beginning Monday and continuing the rest of next week.  ECMWF & GEM (Canadian) models have much higher 850mb. temps, up to 14 degC in the ECMWF.  Combine that with offshore flow in early May and we can hit 85 degrees in Portland.  But for now the GFS is not nearly so strong with the ridge, so I’ll stay with mid 70’s Tuesday-Wednesday.

Either way the generally dry weather continues.  That shortwave disturbance Saturday could give us a shower, but not enough to make me bring in all the yard tools in my case.  Get your dry weather activities finished up…it’s always possible we get wet again in May for quite awhile…Mark

9 Responses to Those Darn Marine Clouds

  1. alex says:


  2. alex says:

    66.0 here still should be a warm night

  3. Justin says:

    Yes, its been a long winter, but I usually don’t hang off every number in these months in the forecast. 80 is nice, but its something that you and I should expect by May. Unless we get in the mid 90’s or above, or there’s a thunderstorm threat, IMO there’s little weather here in the summer that is noteworthy. Just soak up the sun alex, it’ll be here for a while. Though a little dry, its almost perfect weather right now. Personally, I find it nice for a couple of days and boring in the long term.

  4. Ian says:

    oh, and my thermo here at the house is reading 76. i think its picking up some radiated heat from somewhere, not sure though…its on a north facing overhang…about 10 feet from the house, totally sun protected… its hard to explain.
    hey mark, wheres an ideal location in the summer to get an accurate reading? cause where this one is, ive already hit 80 last sunday at the house, lol.

  5. Ian says:

    if youved looked at the visible sattelite loop, it seems theres no way this ridge will hold up till tomorrow. it better though, and i hope these temp forecasts for friday are as lowballed as they were today. called for 68, and its in the low 70’s. if that holds for tomorrow, we could get over 75. and ill be on the boat. thats the main reason i care so much about these petty temps. now in the dead of summer, i realize theres not much difference between 88 and 96… but 72 and 80 feel a lot different. do you get that?

  6. alex says:

    and justin the reason why i am geting so excited is because i havent seen these temp for a while do you know what i mean??

  7. alex says:

    did you see next week will hit 78!!!

  8. Derek Hodges says:

    GFS really heats us up big time, according to this would be upper 80’s
    But ECMWF was cooled at +10, but with an easterly flow would at least be a 77-78. I am going to wait a few days before I put to much stock in this “chance.”

  9. s says:

    I love the clear weather

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