A Week of Summer Temps Ahead

June 18, 2017

11pm Sunday

Apparently I picked the right week and a half to take off this June.  I had randomly picked this time about 9 months ago to take a trip with the family.  The high temps in the 60s and low 70s started the day I left (the 8th), and ended with high temps around 80 in the metro area today a few hours after I arrived back in town.

The sunshine was perfect today for Father’s Day and it appears we’ll see more pleasant summer weather through at least next Sunday.  Models are in good agreement with the first hot western USA ridge of the summer holding on all week just to our south.  This keeps wet weather systems away; all we have to worry about is the strength of onshore flow.  Eastern Oregon will be very hot tomorrow closer to that upper-level ridge

Meanwhile west of the Cascades I think it’s unlikely we get over 90 tomorrow, that’s in spite of 850mb temps around +18 or +19 in the morning.  Don’t think it’ll be a totally comfortable day…with leftover moisture from sprinkles yesterday plus high temps around 90 expect a bit of a “sweaty feel” compared to normal hot days around here.

Enjoy the warm sunshine this week!

Chief Meteorologist Mark Nelsen

Summer Vacation Time

June 10, 2017

The kids are out of school so it’s time for a trip.  I’ll be off all of next week, back at work Sunday the 18th.

No posts during that time

Chief Meteorologist Mark Nelsen

Rose Festival Weather

June 7, 2017

11pm Wednesday

Whew!  Two parades down and one to go.  FOX12 is the Rose Festival station so we broadcast all three parades.  That means everyone around here is VERY interested in the weather this coming Saturday.  Showers are an easy forecast because we’ll have an upper-level low almost directly overhead.  The airmass will be unstable so we’ll see a classic spring-like mix of showers/sunbreaks/downpours/thunder.

I think “bring umbrella, it could be wet” pretty much covers it.  The past statistics are sure interesting:

This time of year (as you probably know) is the transition between spring and summer, which gives us widely varying conditions from year to year.  This time of year you’ve got a little over a 1/3 chance of getting measurable rain on any one day.  I remember the 93 degree parade day…that was a scorcher about 14 years ago.  I don’t remember the 1/2″ rain in 1982.  And we can’t forget the street sweeping and dust masks needed for the 1980 parade…just days after an eruption of Mt. St. Helens.

We haven’t had a real soaker since 2007, most “wet” years we just tend to get a few light showers.


Chief Meteorologist Mark Nelsen


Spring 2017 Wrap-Up: Wet, but Normal Temps

June 6, 2017

7pm Tuesday

We are 6 days into summer, at least from a meteorologist’s viewpoint.  June through August are the 3 warmest months across most of the northern hemisphere and we’re just 2-3 weeks away from decreasing daylight.


So after all the wailing about a “cool and wet spring” how did it turn out?  Take a look at temps:

MarkSpring WrapUp

March and April were cool, but then May ended up as our first warm month since November.  So in the end there was nothing abnormal about our temperatures…very close to average, in fact the most “average” since 2008.


MarkSpring WrapUp2

Yeah, we know…very wet to start, then suddenly the faucet turned off the 2nd half of May.  So it ended up being the 5th wettest on record at PDX and the wettest spring in 5 years.

Those last two weeks of May were sure memorable…a taste of summer we haven’t seen during that same period in quite a few years.  I always find it remarkable how the “faucet” can just suddenly shut off in the Pacific Northwest.  We go from consistent showers and chilly weather and then suddenly no rain for 3 weeks?  Can’t there be a middle ground?

Looking ahead I see one more very warm day tomorrow, then a classic “Rose Festival Low” moves down over the Pacific Northwest Thursday through Sunday.  Check out the huge drop in temperatures on the ECMWF ensemble chart.  This shows temperature around 5,000′ in celsius for the next two weeks.


The screaming message here is that we’re headed into a cooler than normal period for at least a week beginning Thursday.  There are strong hints that we return to normal or even go a bit above by late NEXT week.

We haven’t seen real rain in Portland for about 3 weeks.  The last time we’ve seen more than .01″ was May 17th!  It’s time.  So how much will see?  It’s pretty clear that most of the rain Thursday and beyond will be in the first 3 days (Thursday-Saturday).  Check out the ECMWF model ensemble showing 24 hour rain totals:


Each of the 51 ensemble members are on the upper chart and the lower chart shows the average of all the ensembles.  Pretty clear that the wettest period is early on as I just mentioned, but now there are hints of some additional rain trying to show up that following weekend (17th/18th).  It’s something to keep an eye on.

Enjoy the last summery day Wednesday and make sure you have all your dry weather activities done by Wednesday evening.

Chief Meteorologist Mark Nelsen

Great Blog Post On The Paris Accords

June 5, 2017

7pm Monday…

Last week President Trump decided that the USA would pull out of the nearly world-wide agreement to limit carbon dioxide emissions signed by President Obama in 2015.  Of course the media went nuts with the story, but what does it REALLY mean?  I was thinking of posting about it, but then Professor Cliff Mass up at the UW wrote an EXCELLENT article detailing some facts (and some opinion) on what just happened and what he thinks should happen going forward.  He did a far better job than I ever could!  Here’s a quote:

“…First, the reality check.   Some politicians,  the media, and others have claimed that the loss of the Paris Accord is nearly the end of the world.  In truth, the Paris Accord was a voluntary agreement, with little teeth, and inadequate to do the heavy lifting that is necessary to deal with increasing greenhouse gases.  The voluntary national reductions would have only a minor impact on rising temperature, perhaps reducing the warming by a few degrees fifty years from now.”

and another quote referring to the political wasteland that the Climate Change discussion has become:

“Both the left and the right have used global warming as political tools and as litmus tests of “right thinking.”    Both sides need to stop doing this.  It wasn’t long ago (2008) that Senator McCain, the Republican presidential candidate, talked about the need to deal with global warming.  More recently the Republican party made skepticism about global warming an official tenet of their belief system.   Democrats and “progressives” have taken a similar tack, making  global warming action a central principle of their belief system.  And they have made the serious mistake of connecting climate change to their political goals (such as equity, racism, labor practices) and have participated in exaggerating current climate impacts in order to push folks  to “do the right thing.”

It was such a great read that I insist you read it yourself here: http://cliffmass.blogspot.com/2017/06/after-paris-accord-what-is-best-route.html


Enjoy and discuss…Chief Meteorologist Mark Nelsen


May Ends Warmer & Drier Than Normal

May 30, 2017

11pm Tuesday

For the first time since November we’ve seen a warmer AND drier than average month.  The temperature anomaly across the USA through the 29th:


I think many of us were thinking this spring was going to end up like 2010 or 2011.  Those were especially cool and wet springs.  This May has been VERY different.  Check out the extremely cold anomalies across the entire Western USA those years and compare that to this month.

Now today was especially gloomy/drizzly/showery, although the rain wasn’t measurable at several locations

So our May dry spell has technically continued for 13 days here in Portland


The pattern ahead looks like pretty typical late May and early June weather.  A slight chance for a shower tomorrow afternoon, better chance tomorrow night and Thursday, then showers mainly disappear Friday midday through the middle of next week as temperatures warm to above normal once again.

So we’ve broken out of the cool/wet pattern that much of Spring 2017 was.  Now early summer 2017 (early June) looks pretty normal…at least the first week of it.  Enjoy!

Chief Meteorologist Mark Nelsen


The Vanport Flood: On This Date in 1948

May 30, 2017

69 years ago today, what was once Oregon’s 2nd largest city was erased from the map in hours.  If you’ve never heard of the Vanport Flood, read on…it only happened 5 miles from downtown Portland.

( This post is a repeat from May 2011 with just a few small updates)

I love weather AND history, so I find this flood fascinating, especially since it’s results echo through Portland even in 2011.

I’ll be brief, since it’s a long story.

During World War II (1940-45), huge numbers of workers were brought in to work in the shipyards here in Portland.  There was an urgent need for housing, so a city was quickly built and called VANPORT (Vancouver+Portland) on the flats north of Portland.  That’s the low area west of I-5 around Delta Park where PIR, Heron Lakes, and Delta Park West is now.  That city contained 40,000 at it’s peak, making it the 2nd largest city in the state!

After the war, lots of folks moved away, but there were still around 13,000+ residents there by the Spring of 1948, three years after the war ended.  Even a college had opened in the city for the returning GI’s…the Vanport College.

The winter of 1947-48 brought massive snowfall to the mountains of the Pacific Northwest and Rockies, along with lots of rain.  At this time there were very few dams to hold back spring floods on the Columbia and Snake Rivers…although Grand Coulee and Bonneville Dam both were operational.  The Columbia River rose throughout May 1948 and by Memorial Day Weekend was approaching the 30′ level on the Vancouver gauge.  That’s within 4′ of the all-time high in 1894.  For comparison, that 1948 level is about 14′ higher than the river is right now!  I notice the Portland Housing Authority had put out a notice in the week before saying  “REMEMBER: DIKES ARE SAFE AT PRESENT.

That didn’t happen.  On Memorial Day, May 30th, (used to be on that date instead of the last Monday of May) the railroad dike on the west side of the city (where the railroad is now) burst around 4:20pm.  A 10 foot wall of water went surging into the city.  By sunset the city was inundated and remained so for over a month.  A few factors helped keep the death toll quite low (just 15):  it was the holiday weekend with lots of people out of town and mild temps plus bright daylight kept confusion to a minimum too I suppose.  Here’s the view two weeks later from just about the same vantage point.  Note the triangular are of trees on the edge of the slough in both pictures: 

Interesting to note that the river kept rising, and peaked about the date this picture was taken…at exactly 31′ on the Vancouver gauge.  The flood was the 2nd highest on the Columbia River since record keeping began in the 1800s.

Here are the results:

1. About 1/3 of the residents were of African-American descent; largely settling into north and northeast Portland following the flood.  Lots of  good information about this online which is way out of the scope of a weather blog, but really interesting, especially considering current demographic changes in the area.

2. Vanport College was called “the college that wouldn’t die”, restarted in downtown Portland, and became Portland State University.

3. The town wasn’t rebuilt, but became a raceway, a park, golf course, and wetlands.

4. The Flood Control Act of 1950 spurred more dam building along the Columbia and it’s tributaries, due to the 1948 flood.

Chief Meteorologist Mark Nelsen