Hot Weather Sunday, But Comfortable Work Week Ahead

July 21, 2019

9pm Sunday…

We hit 91 in Portland today; Seattle and Olympia also made it to 90

Todays Observed Highs OrWa 2017

Not exactly a scorcher by late July standards, but this is the first time in five weeks we’ve hit that number.  THAT is rare this time of year.  Yet our temperature is running just about normal since meteorological summer started on July 1st.   Basically we haven’t been getting the typical up/down extremes.  Interesting that the fourth warmest temp so far this year was in early May.

Hottest Days This Year

You likely recall last summer we saw more 90 degree weather than at any point in Portland’s history.   But this year only 3 so far

90 Degree Days Summer Heat

In addition to a warmer atmosphere overhead this weekend, onshore flow off the chilly Pacific Ocean totally shut down.  The usual gusty west wind in the Gorge was calm both days.  But this evening westerly wind has returned through the gaps in the Coast Range.  It has also arrived in Hood River this evening; that assures a cooler day through the Gorge tomorrow plus excellent kiteboarding/windsurfing.

With the return of typical onshore flow, our high temps should drop at least into the mid 80s tomorrow, and down around 80 Tuesday and Wednesday.

Weak upper-level ridging Thursday/Friday lead to warming temps again, but likely just under 90 degrees.

There’s no sign of a big upper-level ridge or cold trough moving over the Pacific Northwest the next 7 days…so, to summarize:


  • High temperatures remain between 78 and 90
  • No day looks totally cloudy
  • Many days will be mainly or all sunny
  • Measurable rain is unlikely in Portland through the end of the month


Chief Meteorologist Mark Nelsen




Vacation Time

July 16, 2019

It’s summer, so I have a few days off the 2nd half of this week.   Will be camping in Cascades and back at work Sunday the 21st.


Light Showers Likely Monday, Much Cooler Too

July 14, 2019

7pm Sunday…

This has been a fantastic July weekend hasn’t it?  Warm, not hot, but temps above average, low humidity, and a mix of clouds/sun.  Today we hit 84 which ties the warmest so far this month.  Quite a string of warm nights too; tomorrow morning we should see our 7th consecutive night in the 60s.  Check out the warm/hot temps today, the hot stuff was from Eugene south.

Todays Observed Highs OrWa 2017

Monday will be MUCH different weatherwise.  If you have something that shouldn’t/can’t get wet, you need to bring it in or cover it before you go to bed tonight.    There is a weak disturbance just offshore, you can see it in the latest GOES-WEST image.  Note a few thunderstorms across the SE quadrant of Oregon too.


That weak system slides inland late tonight, and all models are showing very light rain showers.  Several bring showers over the Portland metro area as soon as right after sunrise.  A slide show here displays the ECMWF, HRRR, GFS, WRF-GFS, & RPM total rain forecast by Monday evening

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Obviously not a gully-washer, but enough to remind us this July is quite a bit different from recent years. The average temperature so far this month is running quite close to normal, held up by the warm nights due to cloud cover. Still, no sign of 90 degree weather through at least the 21st!

AVG Monthly temp_current vs normal

In general we’ll see quite a bit of cloud cover the next four days, but not much rain.   It’ll feel more like June than July.  That’s because an unusually deep upper-level trough is forecast to sit just to our north Thursday/Friday.  Luckily far enough north to keep most rain up there, but still unusual for mid July.


The Positives?  Your air conditioning bill should be minimal to non-existent this year, fire danger is low, and our vegetation isn’t stressed.

The Negatives?  My pool will be too cool after today for 4-5 days so not real useful, water sports companies would like to see hotter/sunnier weather, and hot weather veggies grow slowly in this weather.

Most models are showing a warm-up again in time for next weekend and some show heat beginning around the 22nd/23rd.  But they’ve forecast that hot ridge to our east getting closer twice already this month and as we get closer models decide to keep it farther away.  So I have doubts there will be a significant pattern change in the next 8-12 days.  We’ll see.

Chief Meteorologist Mark Nelsen

A Very Different July & A Nice Weekend Ahead

July 12, 2019

9pm Friday…

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

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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

A Warm & Dry June Turns Into A Cooler July Start

July 7, 2019

8pm Sunday…

Back at work this evening!  After checking out the weather maps/models I can see I’ll be dealing with “why is it so cool?” whining this week.  More on that in a bit.

Apparently I missed a tornado?  Yep, that EF-0 in NE Portland on the 1st

Mid-summer and mid-winter are the tornado “off-season” in Western OR and SW WA.  The 1950-2019 records from SPC show this is the first July tornado on record in our area.  WAY back in the past a few were recorded in July (early 1900s), but that’s before detailed records were kept beginning in 1950.

The first official summer month (June) ended warmer and drier than average.  After an early June heat wave the weather has been pretty normal for early summer.  We haven’t seen a cool June in 8 years!

July has been a different story the past 11 years.  Only 4 have been unusually warm, the rest either cool or just a little warmer than average.

July Month In Review

So what’s ahead?

  1. There is NO sign of hot weather the next 7-14 days.  At least the first half of July will not feature any heat waves and 85+ is very unlikely through the 15th.
  2. Expect more cloud cover than normal to continue through the next week.  I don’t see many days that start sunny.
  3. Later Tuesday through early Thursday will be wet at times and even unusually humid as a subtropical airmass moves overhead.  Overnight lows will warm to above average with the cloud cover and humidity.
  4. Still, temperatures will remain near or only slightly below normal
  5. After some blazing hot summer weather the past few years, we ARE overdue for this kind of weather.

To summarize

  • Portland isn’t sunny Southern California, hot Atlanta, or sunny/dry/hot Denver (in summer).  We live in a temperate marine-influenced climate; notice the greenery all around us?  This is perfectly normal unless it continues for the next 6 weeks.  It doesn’t necessarily mean the entire summer will be cloudy and “cool”.  No need to panic for now if your livelihood depends on renting standup paddleboards.


Maps and models are in good agreement that an upper-level trough pushes up against the Pacific Northwest coastline later Tuesday.  This one has plenty of subtropical moisture.  Sea surface temps offshore are well above average too.  The anomaly map shows a warm “blob” in the Eastern Pacific


WRF-GFS shows the IVT (Integrated Vapor Transport) quite juicy, but most of it is directed north of Oregon Tuesday evening through Wednesday.

ivt.60.0000 Because of that, this doesn’t appear to be a big soaking, well under 1/2″ in western valleys of Oregon and SW Washington.  More likely .10-.25″.  Enough to wet the dust and once again delay fire season.  There are no large fires burning in Oregon or Washington. Excellent news.

Looking farther ahead the ECMWF ensembles show the cool upper-level trough this Wednesday centered offshore


Then this coming weekend.  Trough is there, but a bit weaker.  Temps warm to around average.


Then 10 days ahead (Wednesday the 17th) a very unusual July pattern on both the GFS and ECMWF ensembles.  A large upper level negative anomaly covering the Gulf of Alaska.  Very interesting, but 10 days out.

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Chief Meteorologist Mark Nelsen

Vacation Time

June 29, 2019

I’m on vacation for the first week of July.  Traveling through British Columbia with my son mountain biking.  Back at work Sunday the  7th.  Until then, enjoy this nice view of Osoyoos, BC as a thunderstorm was developing overhead Friday the 28th.   E704650E-3866-4699-A46F-FD580943ED7E.jpeg

Powerful Thunderstorms Move Through Metro Area Wednesday Evening

June 26, 2019

10pm Wednesday…

Whew!  That was exciting wasn’t it?  Between 5-8pm thunderstorms moved through the metro area.  Heaviest rain was right up along the east side of I-205 in east metro.


Officially PDX only saw 0.10″, but some of you went right on over the one inch mark

Rain Totals Metro Area

One video we’ve been showing on FOX12 shows hail accumulating many inches deep along the side of a house as well.  By the way, earlier today a severe thunderstorm covered Hwy 26 with hail near Zigzag

photo hail rhody

Back to the metro area…the line of thunderstorms pushed a large swath of “outflow” wind north and east ahead of it.  Check out the peak gusts!  Similar to a weak winter windstorm event

Wind Peak Gusts Text Panel

This put 26,000 PGE customers out of power (including my home) and 5,000 in Clark county.  That’s one of the largest numbers I’ve seen for thunderstorms in the metro area.  The combo of lightning + wind likely led to the large number of outages.  Many thunderstorm events in our area don’t include the strong wind.

Note there was no Severe Thunderstorm Warning as the storms rolled through.  That’s because there is a specific definition:

  • Large hail, 1″ (quarter size) or larger
  • Damaging wind gusts 58+ mph

So yes, a very exciting thunderstorm but it wasn’t technically considered “severe”.

Looking ahead, tomorrow we’ll be under the influence of the upper-level low offshore.  That means another round of showers/thunderstorms.  But they shouldn’t be as “organized”.  By that I mean they should be more like typical spring thunderstorms with just a few rumbles or flashes of lightning with the showers.  Strong wind is far less likely.

Chief Meteorologist Mark Nelsen