First Heat Wave of 2013 On The Way

6:30am Thursday…

It looks very likely now that we’re headed into a stretch of hot weather to start July, I’ve got an update for you

The Basics:

  • Temps top out around 90, give or take a few degrees, Friday-Sunday in the western valleys, including Portland
  • Quite a bit warmer (hotter) Monday-Wednesday.  High temps somewhere between 95-105 degrees.  At this point the most likely scenario is hottest temps Tuesday with a high right around 100 degrees!
  • Humidity…rarely do we have humid conditions at the same time as hot weather; this will be one of those times.  We may see low temperatures close to 70 early next week, very unusual.

The Details:

I’m still at the weather conference in Nashville, thus the early start!  Models have become quite a bit more organized with the approaching hot ridge of high pressure for early next week.  Upper level ridge seems to be strongest and almost right over us Monday-Wednesday.  Here is the 500mb forecast for Tuesday morning from the ECMWF.

ecmwf_500_tue

Look at those heights!  A 597dm closed high over Eastern Oregon?  I don’t remember the last time I’ve seen heights that high so close to us.

This is an unusual setup that I haven’t seen in many years;  a highly amplified ridge with the sharp and deep upper low well offshore.  Usually we just have a bulky-looking ridge and the appearance is a bit flatter.  The GFS continues to produce much warmer 850mb temps (in some runs) than the ECMWF.  It also has the ridge slightly farther west (right on top of us), giving stronger offshore flow Tuesday-Wednesday.  It would say we’re up around Portland’s record high (107) during that time.  Considering it’s past performance, I’m ignoring it for now.  The ECMWF tops out those temps somewhere just under +25.  With flat or weak offshore flow Tuesday, I could see a high temp at PDX very close to or at 100 degrees.

You can see the difference in the two ensemble charts, the 00z ECMWF and 06z GFS:

tseries_850t_000-360_Portland

tseries_850t_000-384_Portland

Let’s talk humidity…it looks rough this time around!  We have two things going on.  First, plenty of moisture is just sitting over the Pacific Northwest from the recent rainfall, not necessarily just in the ground, but the airmass is very moist.  We’ve got dewpoints around 60 this morning.  Then a capping ridge of high pressure settles overhead without a period of drying north or northeast wind.  AND, areas to our north and east have been wet too.  Models show the humidity hanging around.  This means warmer than normal nights ahead and humid days.  If we get up around 95-100, we could easily have low temps around 70 degrees!

Get ready to hit the water, stay in air-conditioned places, or just plain sweat a lot over the next week!  The bonus is this kind of weather produces wonderful  evening and early morning weather, you’ll step outside and feel warm at sunrise…how “strange” is that?

Chief Meteorologist Mark Nelsen

34 Responses to First Heat Wave of 2013 On The Way

  1. Some aurora pics from Battle Ground tonight.

  2. schmit44 says:

    6/28/2013 Oregon (All) Temperature Summary

    Warmest:
    High:105 at Rye Valley(I-84(2230 ft)
    Low: 74 at Rye Valley(I-84(2230 ft)

    Coldest:
    High:63 at Timberline Lodge(7001 ft)
    Low: 42 at MAZAMA (4596 ft ) & Sand Creek (US 9 (4525 ft ) & KIRK (4519 ft ) & CRAZYMAN FLAT (6100 ft )

    Largest Diurnal Change: 52 degrees
    FOSTER FLAT (98/46 ) (5000 ft )

  3. Down to 78 here in Battle Ground.

    90 for the high, way too muggy for me. I’d much rather have 100 and a nice dry east wind.

    My highest low at this station in the last few years is just 63, so I’m curious if that is broken over the next 5-6 days.

  4. BoringOregon says:

    Getting some thin clouds start to push in my back yard now ?

  5. Josh in Sherwood says:

    It’s chilly outside.

  6. WEATHERDAN says:

    Daytime highs near 100 early next week. Lows around 70. Thunderstorms abound ( Maybe). Kinda makes up for last winters lackluster performance. However several sites are using 1968 as a current analog year to this year. Check out the winter of 1968-1969 in Oregon. You will be astounded.

    • Punxsutawney aka HIOPHIL in Hillsboro says:

      And the fall rains will start in force by mid August if that maps out. Aug-December ’68 was above average in precipitation, at times significantly.

      68-69 was a weather enthusiast’s fall-winter. Arguably one of the best in recorded history.

  7. BoringOregon says:

    What’s that thunder and lightning storm chance today, got some clouds starting to pop off south of me maybe 6 or 10 mils away from me?!?!

  8. Tyler Mode says:

    86 here with a dewpoint of 71. Yuck

  9. vernonia1 says:

    A train and car have collided in Beaverton. TV Highway is closed at 142nd Avenue.

  10. A strange, sultry fog in BG right now.

  11. JJ78259 says:

    Great thunderstorm right over Memphis, power is out in the Hotel and booming outside great storm temp dropped 12 degrees. Lightning like crazy, fun stuff. Really humid yesterday.

  12. schmit44 says:

    6/27/2013 Oregon (All) Temperature Summary

    Warmest:
    High:99 at Rye Valley(I-84(2230 ft)
    Low: 64 at JUNIPR(359 ft) & EW1914 Portland(105 ft)

    Coldest:
    High:56 at Timberline Lodge(7001 ft)
    Low: 36 at DIMLKE (4726 ft )

    Largest Diurnal Change: 51 degrees
    FOSTER FLAT (90/39 ) (5000 ft )

    Heaviest Rainfall:
    0.28″ at AA7OA Astoria(240ft)
    0.25″ at TIDEWATER(2035ft)
    0.23″ at Astoria Regional(10ft)
    0.21″ at DW4535 Cannon Be(23ft)

  13. WEATHERDAN says:

    78 and mostly cloudy here in Salem. Feeling humid outside as well. This could be a very interesting time for weather geeks the next few days. Maybe record heat. Maybe convective weather as well. Sure beats the last few June’s.

    • runrain says:

      Yes, and we still have July and August in front of us!

    • .LONG TERM…THERE WILL BE LITTLE CHANGE IN THE OVERALL SYNOPTIC
      PATTERN EARLY NEXT WEEK AS HIGH PRESSURE WILL CONTINUE TO DOMINATE
      AND TEMPERATURES WILL GROW INCREASINGLY HOTTER MONDAY AND TUESDAY.
      THE LONGWAVE TROUGH WILL DIG FURTHER SOUTH AND FLOW WILL TURN MORE
      SOUTHERLY BY MONDAY. HAVE ADDED A SLIGHT CHANCE FOR THUNDERSTORMS
      MONDAY AND TUESDAY AS MODELS HINT OF INCREASED INSTABILITY AND
      POSSIBLY ELEVATED CONVECTION. TUESDAY LOOKS TO BE THE HOTTEST DAY OF
      THE WEEK WITH TEMPERATURES LIKELY IN THE UPPER 90S. A MARINE PUSH
      TUESDAY NIGHT AND WEDNESDAY WILL RESULT IN AROUND 10 DEGREE COOLING
      FOR WED…WHICH WILL STILL BE WARM…UPPER 80S.

  14. Well the corn will love it. I won’t…

  15. Sifton says:

    Love it, love it, love it!!! It only happens what; maybe 7-10 days out of 365 here?!? No tears please, we’ll all be back in the constant cold, wet & gloomy weather fairly shortly. Enjoy………..

  16. runrain says:

    Go on, Mark. Put that first 100 on the 7 day. C’mon. Do it! Do it! 🙂

    It won’t be comfortable, but I’m still a weather extremist so bring it on! And yes, like Tyler said, we’d better get some storms outta this.

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