91 in Portland Monday

August 13, 2018

11pm Monday

Even with the thick fire smoke overhead we managed to make it over 90 in Portland once again as we head into a 3 day period of hot weather.  That makes today our 27th day reaching 90 this year.  It appears we’re going to break a record this year…likely early next week.

90 Degree Days Summer Heat

Assuming the smoke is at least as thick tomorrow, we should stay in the low-mid 90s once again.  IF we had typical clear blue sky I would forecast 100 degrees for Tuesday.  We have light easterly flow through the Gorge and over the Cascades plus 850mb temps should peak out around +22 by afternoon.  Luckily that smoke coming from fires in British Columbia, Northern Washington, & SW Oregon will keep temps lower.

There’s one other bit of good news, our average temperature begins to fall off tomorrow as we move into the final weeks of summer.

Heat of Summer Hot Temps

EVENTUALLY, it will turn cooler after this blazing hot summer of 2018!

Chief Meteorologist Mark Nelsen

A Rare Showery Saturday In August

August 9, 2018

1pm Thursday

Just a quick post about showers for Saturday.  I know there are lots of outdoor events, weddings, reunions, or camping in my case, this time of year, but at least this will settle the dust.

YES, most of us north of Salem and Newport (along the coastline) will see at least SOME rain during the daytime Saturday.

NO, this is not the beginning of a cool & showery weather pattern.  Hot August weather returns after the weekend.  Enjoy the showers and cool temps!  Highs will likely only make to around 70 or so that day.

The colored areas on these model forecasts (RPM & ECMWF) are where they expect at least .10″ of rain.



Showers could fall anytime between sunrise and 5pm or so Saturday north of Salem. South of there just a sprinkle or two. There could actually be some hefty showers (think spring downpours) NORTH of Longview and Astoria. And yes, I’ll be out there in the weather with everyone else…camping at Silver Falls SP.

There will be no rain south of Eugene along I-5, Mt. Jefferson in the Cascades, in the Gorge east of Cascade Locks, or anywhere else east of the Cascades.  Unless we get a rumble of thunder out of the heftier showers in SW Washington this isn’t a thunderstorm pattern either.

We go right back into hot weather the early part of next week; here’s the ECMWF forecast for the next 10 days.


Ignore the 100 late next week…that’s an “outlier” as we call it.  The model ensembles do not show extremely hot weather later next week.  But Monday/Tuesday WILL be hot.

Chief Meteorologist Mark Nelsen


Hot Weather Through Thursday, Then Cooling

August 6, 2018

11pm Monday

Today we hit 92 in Portland, our 22nd day this year at/above 90 degrees.

90 Degree Days Summer Heat

We are two days into our early August heat wave; I expect three more hot days this week.

Mark Hot Heatwave So Far

Will we hit 100 degrees?  I think it’s unlikely since fire smoke will continue to stream north through the rest of the heat wave.  Today you could see the “dim sun” outside giving the ground a yellowish look.  It sure reminds me of late last summer!  That, even with 850mb temps up around +23 Wednesday & Thursday should keep us just under 100.  But it’ll be close.

There is excellent agreement that an upper-level trough will move overhead late Friday and Saturday, pushing in a 5,000′ thick layer of cool marine air along with a much cooler atmosphere higher up.  That drops us into the 80s Friday and maybe 70s on Saturday.

By the way, as of this moment (through August 6th) we are enduring the 2nd hottest summer on record in Portland.  That’s right behind 2015 and just ahead of 2009.  Of course we still have 3 weeks left in meteorological summer so we’ll see how things turn out in the end.  Regardless, any hopes of a reasonably “cool” or average summer have been dashed by now!

MarkSummer So Far

Notice Salem, which has a much longer period of record, is running at 3rd hottest.  Other cities aren’t even in the top 5.  Seems like this is likely due to a growing urban heat island on top of our warming climate.  Cities are warming more quickly than rural areas or smaller towns.

Try to stay cool the next few days!

Chief Meteorologist Mark Nelsen





3rd Heat Wave of Summer Has Arrived

August 5, 2018

10pm Sunday

The heat was back today…with the entire metro area reaching 90 degrees.

Todays Observed Highs OrWa 2017

The 92 at PDX marks the 21st time we’ve hit 90 this summer

90 Degree Days Summer Heat

Hot high pressure is pushing north through the Intermountain region this evening and that means hot weather sticks around the next few days.

Mark Why So Hot with Smoke

Tomorrow we should warm just slightly, but then a warmer atmosphere overhead Tuesday/Wednesday should push us well into the 90s.  Temperatures up around +22 to +24 at 850mb (around 5,000′) mean we could hit 100 in Portland.  But we don’t get offshore flow, plus another limiting factor for high temps is the thick layer of fire smoke this week.  It arrived this evening in Northwest Oregon and with the upper-level flow (see map above) out of the south/southeast through Thursday we should continue to see a sickly yellow sky obscured at times by even thicker smoke.

By the way, with the hot ridge centered right over Eastern Oregon, some areas in the Columbia Basin could approach 110 degrees Wednesday/Thursday.  Places like Hermiston, Boardman, & the Tri-Cities.

We won’t see any records this week because the big 1981 heat wave put those records up around 105!

Mark Hot Heatwave So Far

Try to stay cool this week; hopefully this will be the last heat wave with unusually warm nights.  It’s been great for the garden but miserable for those of you without air conditioning.

On the rain front…wow it’s dry!

Mark Dry Spells Summer Recent

Today was day #34 with no measurable rain at PDX.  That’s right in line with a typical summer dry spell, but of course the big story this year is the extremely dry late spring.  Very little rain in the past 3 1/2 months!  That’s very stressful on our trees/vegetation, especially since it happened 3 years ago as well.

Let’s hope for a (brief) late summer or early fall soaking!

Chief Meteorologist Mark Nelsen

Vacation Report & Hot Week Ahead

August 4, 2018

I just got back from spending the 2nd half of the week camping down at Diamond Lake, just north of Crater Lake.  It was fun and beautiful as it always is in the Cascades.

Check out the thick fire smoke the 2nd day…we couldn’t even see across the one mile wide lake!


But then I think it was Thursday morning when we woke up to a wind switch with a crystal clear sky.  Note the difference from sunset Wednesday to Thursday morning

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Well, one big thing happened while I was gone; the all-important position of the hot upper-level ridge for next week is forecast to be much closer to us instead of well to our east.  Check out the map I showed you this past Monday…for this coming Tuesday.  It was looking cool & showery with a chilly upper-level trough over the Pacific Northwest.  See the hot ridge over the southern Rockies?


But just 24-48 hours later models decided that hot western ridge was going to bounce back up after a brief cooling this week.  Here’s the current forecast for the same time (Tuesday AM) from this morning’s run of the ECMWF ensembles:


Ugh, the cool trough is way offshore and a hot ridge is developing overhead.  By Thursday it’s extremely hot anywhere east of the Cascades and well into the 90s west of the Cascades.


One other big issue this week is that upper-level flow is from the south…expect lots of fire smoke throughout the week.  It’ll probably come and go, but lots of sickly yellow skies are ahead.  We’ve also had some lightning strikes in both the Oregon and Washington Cascades today…that’s bad news just before a heat wave too.

I’ll be back at work tomorrow with a more detailed look at this upcoming week’s forecast.  I’ll leave you with a neat view from the top of Mt. Bailey, about 3,000′ above Diamond Lake.  My son & I climbed it on Friday.  We only saw one person…and Brutus her dog.  A very quiet place!  Make sure you click on it for the panorama view: