Saturday Update: Hot, but Not Record Setting Next Few Days

June 29, 2013

8am Saturday…

I’m back in town today; a very nice arrival into PDX last night too with temps in the lower 80s.  My wife and I both noticed how “fresh” it smelled when we got out to our car…just that Pacific Northwest summer feel I suppose.

As the PDX NWS forecast discussion says…an interesting forecast pattern the next few days…

The Highlights:

  • A weak push from the ocean last night means a little cooler today, so high temps should drop into the upper 80s, not really hot by Portland standards, but not noticeably different from yesterday.
  • Back to hot Sunday-Tuesday
  • Temps probably top out around 92-95 Monday and/or Tuesday, not record-setting since records are 105-102 for those days!
  • A thunderstorm is possible anywhere inland the next few days, but extremely hard to pinpoint who gets a storm and when

 

Another very warm night last night, but there is a change that occurred;  cooler ocean air with lower dewpoints moved inland.  I see dewpoints are below 60 here in the metro area.  As a result we’ll probably be just a few notches cooler today even though we are running 5 degrees warmer at 8am.

A blowup of thunderstorms occurred in the middle of the night/early this morning over in northeast Oregon and eastern Washington.  Check out the lightning!  We have a nice deep flow of moisture coming up from the south the next 3-4 days, somewhat unusual for our area.  Sure, a strong ridge of high pressure nearby to keep the action capped most of the time.  But if a disturbance, even a weak one, rides up the southerly flow we could get a thunderstorm anywhere at any time of the day.  Very tough to forecast.

lightning1

In the past several runs models have really been struggling with placement and strength of the upper level ridge the next few days.   The 00z GFS really backed off the heat, and the NAM is following.  In fact the 12z NAM has us only in the 80s Monday and Tuesday!  The 6z GFS was back to a little warmer and prolongs the warm temps through Independence Day (Thursday).  The old reliable ECMWF, which definitely seems more stable the past few years, is staying with it’s “HOT, BUT NOT TOO HOT” theme for the early part of the week.  Note the 6z GFS ensemble chart first:

tseries_850t_000-384_Portland

 

Then the 00z ECMWF:

tseries_850t_000-360_Portland

 

The ECMWF has been very solid at a +20 to +23 degree 850mb temp peak Monday-Tuesday for many runs while the GFS was swinging wildly out of control.  You can see the operational run (blue) is well above the ensemble mean for the latter half of the week.  It’s a matter of how much of  “dent” we get in the ridging later next week.  The 6z GFS chart is similar with the operational much warmer than the rest of the members.  The BIG PICTURE is above average temps are likely the next 10 days or so…probably.

We’ll see how this pans out, but this is definitely not any sort of historic or record-setting heatwave coming up west of the Cascades.  Just a quick jump into summer.

Now for a REAL heatwave, check this out from the Las Vegas NWS office:

vegas

Chief Meteorologist Mark Nelsen