The Summer Doldrums; Mild Weather Continues…

July 8, 2013

I came in today, looked at the maps, and wondered what I was possibly going to talk about for 2-3 minutes in each show this evening.  Still not sure, but somehow I always fill the time.

The Highlights

  • No rain in sight
  • Warmer Tuesday, then cooler, then warmer again early next week
  • No heatwave in sight
  • No thunderstorms for most of our viewing area in the next week
  • Definitely no thunderstorms west of the Cascades

We are in the deadest time of the year here in the Pacific Northwest, but that means great weather for summer vacations!  If you have outdoor plans in the next week  (probably longer), you have dependably mild to warm weather and no rain in the forecast.

Here are the usual charts/maps…

12z & 18z GFS ensemble charts:


tseries_850t_000-384_Portland (1)

12z ECMWF ensemble chart:


Last night’s monthly ECMWF run, the weekly charts of 500mb height:





The big picture with the ensemble charts?  Operational runs of both the GFS and ECMWF are a little on the warm side for the first few days of next week, pushing the hot western ridge a bit closer to us than it will actually get.  I believe that considering that’s what is occurring right now.  Remember that at one point it appeared we might get into the 90s either today or tomorrow.  In fact, on the 7 Day our forecasts for today and tomorrow were 88 and 90 in the early/middle part of last week.  As a result, I didn’t get too crazy with low-mid 90s Sunday and beyond.

Other than that…wow, boring.

We are approaching our warmest time of year, here’s a little TV graphic showing average high temps in Portland peaking out at 81 or higher from July 13th-August 14th.  We even average 82 for a high for about two weeks at the end of July and early August.


Chief Meteorologist Mark Nelsen

Happy 4th of July!

July 3, 2013


Independence Day looks very nice across the Pacific Northwest, just some morning clouds along the Columbia River and the coastline.  All areas will be cooler too.

Here in Portland we should top out right around average for this time of year…78 degrees.


By the way, we haven’t seen measurable rainfall here in Portland on the 4th since 2000!  That makes 13 consecutive dry holidays.


Curiously, the chance for measurable rainfall is highest on July 4th when compared to all other July days.  Strange eh?  It’s not strange that the average drops off dramatically later in the month of course…the last week of July and early August are our driest time of the year…on average.

I’ll be off on Thursday but back here on Friday.

Chief Meteorologist Mark Nelsen


July 3, 2013

I had a viewer ask me for the dew point graphic I used last night on the 10pm newscast (really!).  We don’t talk about it much here for two reasons:  First, we rarely get hot and humid weather.  Second, it’s a tricky concept to explain in a short weathercast.  Basically the higher the number the more moisture there is in the air.  70+ is the disgusting southeastern USA summer humidity.  Less than 60 is normal in the Pacific Northwest on summer days.  Right now it’s in the 40s!  Very dry and notice the haze is gone this afternoon


Brief Heat Wave Ends, But Summer Continues

July 2, 2013

6pm Tuesday…

We failed to hit 90 here in Portland today as we saw just enough cooling working in off the Pacific Ocean to keep the temps down a few degrees.


Anywhere within 10-20 miles of the Columbia River from Kelso to Troutdale was a bit cooler today as well.  Now down in the Willamette Valley the cooling didn’t penetrate very far.  Salem and Eugene hit 93 and 96 respectively, still plenty hot!  Take at look at the highs eastside…a real scorcher:



By the way, today was the 3rd day in a row with a record warm overnight temp, that’s assuming we don’t drop below 63 before midnight…very unlikely:


Slightly increased onshore flow tomorrow means slightly cooler temps again, probably just 85 at best here in the metro area.  Then much cooler temps Thursday-Saturday as a decent upper-level trough passes by to the north.  The 500mb heights go from around 592dm right now to 575dm Friday morning.  This setup usually produces a big onshore push, but most likely not deep enough for morning drizzle inland.  Then some ridging (though not strong) rebounds Sunday into the middle of next week.

Very good model agreement (surprise!) on these pattern changes the next 7 days.  Look at the 12z GFS and 12z ECMWF ensemble charts:



Both show the big dip to below average Thursday night and Friday then warming afterwards.

So no rain in sight and summer weather is here…enjoy!

Chief Meteorologist Mark Nelsen

Monday PM: Slightly Cooler Today

July 1, 2013

1pm temps are running 2-5 degrees cooler than yesterday at the same time, and we started a bit warmer as well.  That’s a sign we’ve lost the very weak offshore flow we had yesterday morning.  Yesterday the pressure gradient through the Gorge was flat at midday, today it’s up to 3.5 millibars PDX-DLS.  Nature’s air conditioner (Pacific Ocean) is keeping us from having a major heatwave this time around.


Still, we’ll top out in the 90-95 degree range today.  Hot, but nothing too unusual for July.  But what a warm night…66 was the low at PDX.

I’m doing all the shows today so no time for a bunch of tech-talk and maps, maybe later.