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  • Updated

Friday, July 30th, 3:50 P.M. 

Happy Friday!

Clouds and a smoky haze kept today a bit cooler than expected, but it was still very warm with highs making it into the mid 90s around the metro area. We are seeing some showers on the radar, but most of the rain is very light and evaporating before it hits the ground. A chance of thunderstorms or light showers will linger tonight, especially over the Cascades.

Saturday brings more high clouds and a smoky haze above with highs in the low 90s. Expect that smoke to stick around on Sunday, but it should have little to no impact on our air quality.

After a couple more 90 degree days on Monday and Tuesday, things cool off midweek. Thursday and Friday bring our first decent chance of showers in over a month and a half!

  • Posted

9pm Monday...

Quite a change today eh? Temperatures soared from near/below freezing yesterday evening into the upper 40s or even lower 50s today. The southwest wind did the trick; even Troutdale made it to 48. I think the McMinnville sensor may be about 5-6 degrees off, more likely 50 there.

A westerly surge of "warm" air is working through the Gorge. Cascade Locks has jumped into the lower 40s and Hood River should see it soon. By sunrise a 40-45 degree breeze should have made it all the way to Maryhill & beyond. The pressure gradient is now WESTERLY for the first time since last Wednesday in the Gorge. This cold event has ended.

The damage to the power grid is the biggest I've seen since the 1995 windstorm. Looks like around 300,000 PGE customers have been out at one time in two different "waves of ice". The first Friday night in the northern/central Willamette Valley, then the 2nd yesterday evening/last night in south and east metro areas. There was some overlap in those south metro spots. Here are some preliminary ice accumulation numbers. It's amazing how well models did showing the thick ice glazing in the southern half of metro area. I've colored the areas where we generally saw 1/2" or more.

The rest of this week features "normal" weather. Drier conditions tomorrow with just a few scattered showers, but heavy Cascade snowfall. Then ONE dry day Wednesday before rains resume Thursday & beyond.

A few notes:

  1. We don't see a February 1996 setup with flooding following the melt. There's no heavy rain on the way to bring us a flood.
  2. I don't expect re-freezing of wet roads tonight. Too mild with cloud cover for just about all areas west of the Cascades
  3. There's no sign of low elevation cold/snow in the next 10 days, but we'll remain on the cool side with lots of rain

Chief Meteorologist Mark Nelsen

  • Posted

I took a full week off right when the heat wave began last week. 6 days of camping in the Cascades included Diamond & Paulina lakes (excellent!). One night at Still Creek campground too (not as excellent). Of course we ended up right around 100 degrees the first day of that heat wave, then cloud cover from the south kept us in the 90s the 2nd day. Then a third day in the 90s this past Monday before cooler marine air made an appearance. That first day all official observing stations in the metro area hit 100 except Portland & Vancouver. Troutdale was offline; inconvenient timing. Aurora and Eugene both hit 101.

The result is that we’ve just about hit our yearly “allotment” of 90 degree days. One more than last year…so far.

Porltand DOES get more 90 degree weather than in the past. Check out the average for each decade. The 1950s and 60s saw far fewer hot days than the last 20 years.

DECADE# of 90 Degree DaysAvg per year


Today I came into work and realized it was going to be the most boring forecast of the entire summer! This is GREAT news for all of us though; we are in a very stable late summer weather pattern through the foreseeable future. Many of us will consider these last 8 days of the month just about perfect:

  1. ABUNDANT SUNSHINE Models aren’t showing much marine layer west of the Cascades = very little morning cloud cover, if at all
  2. NO HOT WEATHER Just enough onshore flow to keep us in the 78-88 degree range
  3. COOLER NIGHTS Longer late August nights + dry airmass = overnight lows well down into the 50s, hardly a need for air conditioning.
  4. NO FIRE SMOKE All that smoke from California and central/eastern Oregon wildfires remains south of Medford and east of the Cascades

We are seeing a pleasant weather pattern because upper level heights are a bit above normal. Here’s the ECMWF ensemble forecast of 500mb heights for later this week (Friday), note the above average heights (warm colors). Click for a larger view

Next weekend a cool upper-level disturbance drops down just to our east, bringing early Fall temps to the Rockies, but leaving us dry. This is Sunday the 30th.

Notice that new ridge developing just to our west; models show that ridge becoming the dominant feature overhead in the week leading up to Labor Day. Here’s Wednesday the 2nd

Looking WAY out there, to Labor Day Weekend, models show that ridging sticking around; we may yet see additional 90 degree weather in the next 2-3 weeks. Here’s the ECMWF & GEM models for Labor Day, the 7th of September. Depending on your browser, this may or may not show with a “slider” to move between the two.


The main point?

There’s no sign of an early rainy spell as we head into the first few days of September. Warm and dry late summer weather continues until further notice.

We are now regularly producing a weather podcast here at KPTV. The 3rd episode this month was just posted online. This week while I was on vacation, Brian/Anne/Jeff got together. Hear about the “firenado”, record heat, and Anne’s chicken fears… Make sure you subscribe and rate/review if you get a chance.

Chief Meteorologist Mark Nelsen

  • Posted

Time for a break from the news.  Forget viruses and crashing financial markets, let’s talk about weather!

Spring is back today after three very cold days (for mid-March).  Portland’s high temperature jumped 14 degrees today!


The 42 degree high Saturday broke a record for coldest *high* temperature on March 14th.  Friday and Sunday were close.

Meanwhile, EVERYONE saw a much warmer day today.  Check out the lower 60s along the coast.

Todays Observed Highs OrWa 2017

It only took one day for the unseasonably cold airmass east of the Cascades to modify substantially under the strong mid-March sunshine.  Hood River jumped from 34 to 50 from Sunday to this afternoon.  Government Camp 29 to 45.  That doesn’t happen in winter (December-February).  So our cold east wind Sunday became a mild/warming easterly wind today.

Tomorrow the east wind dies down, that plus 850mb temps around +4 should push us to 60 degrees once again.

Later this week an upper-level disturbance drops down along the West Coast, although it appears just about all the cloud cover and rain stays offshore.  It’s headed for California, not us.  The result is very nice late March weather.  This ECMWF model cloud cover loop covers this evening through Friday morning.  You can see that system swirling offshore Thursday night and early Friday.


This month has been dry.  Sure, somehow PDX picked up almost 3/4″ precipitation Friday/Saturday, but the month is running well below average across most of the West


Every month of this cold season, except January, has been drier than average.

Rain So Far This Month Or and Wa Earth Scene

As that trough passes by, weak upper-level ridging builds overhead Friday/Saturday.  This MAY lead to the warmest temperatures so far this season.  850mb temps come up to around +3 or +4.  That should give us highs 60-65 those two days.

Beyond Saturday?  Models are in pretty good agreement we turn a bit wetter for what WAS Oregon’s Spring Break.  Now it has turned into a very long break that has already begun.

Check out the ensemble precipitation forecast from the ECMWF for the next two weeks.  Most members dry through Sunday, but then a clear signal for wet weather by next Monday.  The lower (green) section shows the ensemble average precipitation accumulation.  Looks wet next week…


That’s it for now, enjoy the sunshine.

Chief Meteorologist Mark Nelsen

  • Posted

9pm Tuesday…

Whew…today was a scorcher, especially for so late in the summer season.  Let’s go over the numbers…

Several spots in the Willamette Valley hit 100 degrees, the hottest temps of Summer 2019.  Salem, Eugene, Aurora, and down in Roseburg too.

Todays Observed Highs OrWa 2017

Check out those coastal numbers!  Upper 80s to upper 90s throughout the FOX12 viewing area from Yachats to Long Beach.  When wind remains offshore through 1-2pm those temperatures can soar all the way down to the ocean beaches.

You can see we hit 98 in Portland, a new record for August 27th.  This also tied the highest temperature of Summer 2019 set in early June.

Hottest Days This Year

I had mentioned over the past 5-6 days this would be a classic late summer/early fall east wind event; it sure did deliver!  In one hour from 9:15 to 10:15 am Tillamook’s temperaure jumped 23 degrees! (63 to 86).  At PDX it jumped from 81 to 91 in one hour between 11am and Noon.

Easterly wind gusts made it to 52 mph at Vista House.  That’s pretty strong for late summer.

For the geeks, the 850 millibar temperature made it to 24.4 degrees on this afternoon’s sounding.  That’s right up with the big late summer heatwaves.  In fact during a ten-year period 1999 to 2009, only one P.M. sounding (out of 300+) had a higher temperature!  That day it jumped to 102 at PDX; likely earlier in the month.

What’s ahead?  Temperatures should just barely drop to 60 in the city by sunrise, and into the 50s outlying areas.   That’s thanks to nights two hours longer than a June or early July heatwave.  Areas that continue to see the easterly breeze (near Gorge and higher hills) may stay in the lower 70s.

Mark Forecast Night City Temps

Tomorrow the hot thermal trough (area of lowest pressure) shifts east of the Cascades late in the day.  That cools the coastline, but we’ll still get up to between 95-99 degrees in the metro area.  Another scorcher, but without the hot wind.

A weak upper-level disturbance passes overhead tomorrow night and early Thursday.  The ECMWF and WRF-GFS (UW) continue to insist showers pop up with this during that time.  The 18z ECMWF brings a swath of showers across NW Oregon and SW Washington through the first half of Thursday.


A bit wetter than other models though.  We’ll see.  Regardless, don’t leave anything outside tomorrow night just in case.  Of course temperatures will drop at least 15 degrees (or even 20) Thursday due to morning clouds/showers and a push of marine air.  Should be refreshing.

Beyond tomorrow we settle into a typical late-summer pattern of morning clouds and afternoon sunshine.  Labor Day Weekend will likely see highs between 75-82 degrees in Portland with varying amounts of cloud cover.

Chief Meteorologist Mark Nelsen

  • Posted

What a spectacular summer day, not hot, humid, or cloudy & cool. The comments I keep getting are that this is “just right”.  Today we hit 84 in Portland, above the average high of 80.  Warmest day so far this month.  We’ve also seen a string of warm nights recently, this morning was our 4th staying above 60 degrees.   The humid weather from Wednesday is long gone too, dewpoints briefly even dropped into the 40s late this afternoon.

This July has been…NORMAL temperature-wise, but cloudier than average.  Out of 12 days we’ve seen NO clear days, 8 partly cloudy days, and 4 cloudy.  I suspect that’s the reason I’ve been seeing some complaining online.  If you want to hit the local lake/river/pool, it’s much chillier to do it under cloud cover.  In fact yesterday/today was the first time I’ve made good use of my Craigslist-special pool this season.  I was out of town for that heat wave in early June.

Todays Observed Highs OrWa 2017

As mentioned in the previous post, we are overdue for an “average” summer instead of another blazing hot one.  Even with a warming globe, that doesn’t mean every year turns warmer and warmer in a steady line.  There will still be the usual ups/downs and cyclical periods; but the GENERAL movement will be uphill over time.  Also, we’ve had many summers that are about average in July and then August/September turn hot.  We’ll see.  Last year the blazing hot summer kicked into high gear on this date.  The following 19 days were crazy, all except 4 above 90 degrees:

July 2018 Historic Heat Wave Stats

I know some of us want more sun and hot temps, but the 84 today was sure nice in comparison.

This weekend looks pleasant again with a relatively thin marine layer leading to plenty of afternoon sunshine each day.  On Monday that layer thickens a bit so expect more cloud cover for the start of the work week.  850mb temps (temperature in celsius around 4,000′) drop a little Monday as well as a weak upper-level trough moves overhead.

As I mentioned in the post early this week, an unusual (for mid-summer) setup is on the way for later next week.  A highly anomalous deep trough cruises across the Gulf of Alaska midweek and drops into the Pacific Northwest late next week or the weekend of the 20th.  Check out the 500mb anomaly chart for Wednesday and again Friday

That’s what we might see in June, but unusual for July.  At this point it appear most of the significant rain may be headed for Washington and BC.   Oregon would see far less.

How much rain down here?  Initial look, remember it’s 5-7 days away, but a tenth of an inch in the western valleys and less than 1″ in the northern Oregon Cascades seems like a good guess.  Here’s the 12z ECMWF model forecast:

ECMWF Precipitation Accumulation

Enjoy your weekend and keep in mind that we MIGHT see showery/cool weather about a week from now.

Chief Meteorologist Mark Nelsen

  • Posted

Today was a typical “morning clouds then afternoon sun” day west of the Cascades.  We had a relatively strong push of marine air overnight.  That marine layer is thinning now which means less morning cloud cover Friday + more sunshine.  That equals warmer temps; although today’s 66 in Portland only came down to average for May 2nd

Todays Observed Highs OrWa 2017

We have a very nice early May weekend on the way.

Onshore flow weakens dramatically Saturday for a good 6-10 degree jump in temps with little/no morning cloud cover west of the Cascades.  That should push us into the mid 70s.  Expect similar weather Sunday, although several models are bringing a better push of morning clouds & cooler temps that day.  Regardless, a dry May weekend with plenty of sunshine plus temps above average = very nice!

But now things are getting strange again…

During the past two weeks we’ve seen little/no rain for most of us west of the Cascades.

1. That DOES sometimes happen in the springtime for a week or so, but dry spells to two weeks are unusual.

2. Now add in another week of dry weather on the way and that’s VERY unusual.  I just took a look at rain records here in Portland.  This is crazy.  Take the last two weeks of April, then add in these first 9 days of May (assuming little/no rain falls through next Thursday).

3. This year is the driest, followed by…last year!

Three of the five driest late April through early May periods have been in the past few years.  That’s 2019, 2018, & 2015.    We know what happened in those other two years…very warm/hot summers.

We have also seen 6 consecutive dry Mays in Oregon Climate Zone #2 (lower elevations west of Cascades).  That’s after the memorable chilly & wet springs 2010-2012


This does make me suspect (along with other evidence) that our warming/changing climate has a part in this.  Anecdotally, it seems we are seeing more episodes of upper-level ridging near/over the west coast of North America the past 5-6 years.  Remember last winter we (again) didn’t have any sort of typical stormy westerly flow.  The action (snow & cold) came from a big ridge to our west and cold northerly flow coming out of Canada.  Also it seems we are seeing higher “upper-level heights” in the warm season.  In this case everything would be pushed to the north; Portland’s warm season weather would become more like Roseburg.  Then Roseburg is more like Medford etc…  Again, this is anecdotal and based on what I’ve seen all these years forecasting in our area.

As Pete Ferryman said yesterday, maybe the old saying “summer begins on July 5th” will disappear in time.  We’ll see.

In the short term we have a very stable pattern offshore with an upper-level ridge over a cool upper-low approaching California


That ridge strengthens and snuggles right up to the Pacific Northwest through the middle of next week.  Notice ensemble averages of the ECMWF, GFS, & GEM models all show the same setup for NEXT WEDNESDAY.  At this point 850mb temps climb above +10 and offshore (easterly flow) may develop

If so, we’ll see our first 80s of the season the 2nd half of next week.  Here are the forecast numbers I’m using tonight:

Forecast Highs Next 7 Day Meteogram DCA

Our average high temperature now through May 9th is 65-67 degrees so this is well above average.  Not record-setting by any means since they are around 90 this time of year.

What about rain?  Both the GFS and ECMWF ensemble members say we might see some sort of cooler/showery pattern show up around the 13th/14th.  That’s still quite a way off.  Click for a better view

Enjoy the weekend!