Vacation Time

April 23, 2017

4pm Sunday…

Yes, I know many of us were just on spring break.  But this coming week I’ll be on an anniversary trip with my wife.  I’ll be wearing these…pretty cool eh?


Hurricane themed board shorts.  Nice streamlines, satellite imagery & weather maps while swimming.  A weather geek’s dream.

I’ll be back at work Monday May 1st.

Chief Meteorologist Mark Nelsen

Another Wet Month

April 20, 2017

11pm Thursday…

We are now above normal (for rain) this month…heading toward a 3″ rain total.  I have a feeling it’ll be more like 4″ plus by the end of the month.  It’s pretty clear that we’re going to be getting hit with a series of wet weather systems this last work week of the month

Rainfall so far this month_compared to normal or prev. records

So hunker down and try to survive another showery week ahead.  EVENTUALLY we warm up and dry out at some point.  Of course the big question is when will that happen?  We’ll see.

We’ve been very busy the past 2 weeks revamping all our weather graphics.  In fact the newscasts tomorrow starting at noon should look much different.  TV stations do this from time to time and a fresh graphic look is way overdue.   I’m confident the change will brighten things up quite a bit!

Chief Meteorologist Mark Nelsen

A New Record…Still No 65 Degree Days

April 18, 2017

11pm Tuesday…

We just set a new record today; a chilly one!

WE’VE NEVER GONE THIS FAR INTO THE SPRING SEASON WITHOUT HITTING 65 DEGREES.  The previous records were in April 1945 & 1950.  In those years (as you see below), we finally made it over 65 on the 18th of the month. We didn’t do that today so now we’re in uncharted territory for PDX and a new record has been set for latest “FIRST 65 DEGREE DAY”.  Of course those records go back about 80 years.


Check out the warmest temperature each of the last 11 Aprils in Portland:


It’s pretty typical to see 75 or even low 80s at some point during the month.  But I think that’s unlikely this year as we stay in a regime with weather systems frequently passing through the region.  Still no sign of anything more than one or two days with brief upper-level ridging.  Take a look at the 12z ECMWF 850mb ensemble forecast:


There is very good agreement through the 27th with these ensembles.  You see the spike of warm air later Friday through SaturdayAM.  But then it’s back down to near/below normal temps up around that 5,000′ elevation.  There is quite a bit of “noise” right in the last couple of days this month.  That means the different ensemble members diverge a bit, but that’s normal for 10+ days out.  This evening’s GEFS (GFS ensembles) is quite similar:


except there are quite a few warmer ensembles around the end of the month.  Even with what we consider a “cool pattern”, this month has still be pretty reasonable.  Most stations in Oregon are running at or less than 2 degrees below normal.  Here’s the USA analysis, which seems a bit cool compared to actual observations for our area:


Compare it to the first 17 days of April last year!  Wow…what a crazy warm month that was and a temperature pattern across the USA reversed from this year.


By the way…even with the “cool-ish” 10 days ahead, our daylight does keep increasing.


The sun set at 8:01pm in Portland today and will set beyond 8pm for the next 4 months.  The next “pre-8pm” sunset will be the weekend before Labor Day (August 26th).  Enjoy the long days!

Chief Meteorologist Mark Nelsen


The Rain Is Back

April 16, 2017


It’s the start of another work week for me (I work Sunday through Thursday afternoons/evening) and I see the rain is back.  A line of showers with a few embedded thunderstorms is moving north through the Willamette Valley so we might see a flash or hear a rumble in the next few hours.  This is an upper-level low that is “kicking out” over the Pacific Northwest.  By that I mean it was sitting offshore and now it’s getting caught up into the (weak) jet stream.  Plenty of lifting so some of the showers the next 3-4 hours could be heavy.

Beyond that we are in a showery pattern for the next week.  Temperatures will remain near or just a notch below normal.  At this point it appears Wednesday and Friday have the best chance at remaining dry.  Of course on the days we get showers there is the possibility of thunder since it’s spring.  Right now Tuesday holds the highest hope for a rumble.

Check out the warm temps today…for some of us in the metro area it was the warmest so far this spring…pretty nice for Easter Sunday don’t you think?


We only hit 63 degrees today in Portland, which means we still haven’t hit 64, or for that matter 65 yet this season.  That’s very unusual.


So has it been the “Coldest April in XXXX Years?“.  No, in fact even through just April 17th, we’re running warmer than the ENTIRE months of April 2011 or April 2008.  It appears we won’t be in the top ten cold Aprils either.  That’s assuming no real cold pattern suddenly appears in the last week of the month.  What’s been happening this spring is a slightly below normal pattern temperature-wise, but no extremely cold periods.  And, more noticeable, no (even brief) periods of warm weather.  Sure, a day or two here and there where the high gets 1-3 degrees above normal.   But typically in the spring we have a cool and showery week (or two) followed by 3-4 days of sunshine and 60s/70s.  We can even hit 80 in April although that is quite rare….except for last year.  More on that in tomorrow’s post.  Here’s a nice tidbit from a posting last year that this time…


This tells me that we have been overdue for a cool spring after 3 warm ones…it’s payback time!

Chief Meteorologist Mark Nelsen

Happy Easter!

April 16, 2017

6pm Sunday…

Here’s a great Easter Sunday sunrise shot by David Leahy.


Of course he was over at the Wooden Shoe Tulip Festival near Woodburn.  Seems perfect for this holiday doesn’t it?

We’ve had a perfect weekend (for mid-April).  This is the first time we’ve had a dry and warm weekend since sometime last fall.  I got tons of yard work done the past few days and then today was a great day with the family.  Potatoes, broccoli, spinach & strawberries are in the ground and ready for an evening soaking.

But I’m back at work this afternoon and looking at maps/models…I’ll put up a fresh posting later this evening after I finish the forecasting.

Chief Meteorologist Mark Nelsen

Wrap Up: A Historic April Wind Storm

April 7, 2017

2pm Friday

The wind is slowly continuing to die off this afternoon and we’ll be down to just breezes by this evening.

I missed a haircut today due to this windstorm since I rushed into work, but it appears that’s a minor issue compared to what some of you have gone through.  There is now a ton of firewood available in the metro area since LOTS of trees have come down.  And it appears at least one person’s death was caused by falling trees/limbs in SW Portland.

This was most likely the strongest April windstorm in the metro area since the April 14 1957 event.  In fact it was quite similar to that storm with respect to track and windspeed reports.


Note that a stronger gust did hit the airport on the day of the Vancouver Tornado in 1972, but that wasn’t a widespread southerly windstorm.  As mentioned in a previous posting the airport wind sensor was quite close to the tornado when it first touched down on the Oregon side of the river.

This wind storm brought the most widespread power outages for PGE since the December 2006 “Hannukah Eve” storm as well.


1 in 5 customers had at least a brief interruption and some of us will likely be out of power for a few days.  At least in April we won’t get too cold!

Hardest hit was the west and central metro area, including SE Portland where OMSI recorded a gust to 76 mph on their rooftop sensor.  Note the gusts to 60 mph in SW Portland and Hillsboro.  That’s quite high for those areas.  In fact Hillsboro airport hitting 60 mph IS a rare event indeed.


You’ll notice the lower speeds east of I-205.  That’s okay, they get plenty of wind all winter long.  And poor Vista House got left out of this storm…just 32 mph.  The Gorge doesn’t get strong south wind storms, okay, maybe once every 20-30 years, but that’s it.  One other note.  There is a wind sensor up on SW Portland that shows up online.  It recorded gusts 80-101 mph for several hours this morning.  I’ve skipped over it because either A) It’s high up on a transmission tower or B) the sensor has gone bad.  There’s no way the wind was regularly gusting at that speed right in a neighborhood in SW Portland near ground level.


Today’s event was a glimpse into the future of weather forecasting.  The models beat the human forecasters!  Just about every model clearly advertised wind gusts in the 50-70 mph range during the morning to midday hours, some were even a bit stronger.  I was a bit doubtful so I dropped those numbers a bit to 40-55 mph gusts (which was slightly low, but close enough).  The NWS forecast gusts 45-50 mph.  There was a Wind Advisory out for the valleys but no High Wind Warning (criteria is gusts above 58 mph) out for this storm.   Using the classic rule of Eugene to Olympia pressure gradient (10 millibars), you would only get gusts in the 30-40 mph range.  Instead we immediately jumped into the 50-70 mph range right away this morning.  That strong wind just a couple thousand feet up mixed down to sea-level perfectly and the model simulations nailed it while the humans were doubting it.  This includes the HRRR, NAM, NAM-MM5, WRF-GFS, & ECMWF.

This will happen more often in the future and I expect within 10 years the vast majority of the time models will be correct and the humans will just be left to “babysit” the output.

This weekend we’ll see showers and sunbreaks as a cool airmass sits overhead Saturday, then mainly (or all) dry Sunday since we’ll be waiting for a front to come through Sunday PM.

For future analysis, here are 4 different model forecasts (wind gusts):

Chief Meteorologist Mark Nelsen

Peak Wind Gusts So Far…Storm Update

April 7, 2017

At 9am over 130,000 PGE customers are out of power and trees are down all over the place.

This is the type of storm where gusts will come and go.  It might even be calm for a half hour, then a shower goes through and you get a gust to 50 mph.  In general the wind dies down after the noon hour.

Here at the peak gusts so far in mph..some weather stations (Hillsboro & Chehalem Mtn so far) have stopped reporting due to power outages:

Portland:  56  (official gust at airport)

Hillsboro: 61

Vancouver: 44

Scappoose: 53

Troutdale: 48

Aurora: 53

McMinnville: 54

Salem: 60

Forest Grove: 53

Dallas:  68

Chehalem Mtn. 73

Now here’s the tricky one…there is a reliable weather station in the West Hills near Council Crest.  Typically in the past the observations have been just fine.  Yet it has recorded several gusts from 80-98 mph the past two hours.  It may be on a tower and if so those speeds are possible.  And Chehalem Mtn. gusted to 73 before the power went out so one would assume it went higher up there too.  Interesting eh???

After noon the wind should die down quite a bit.

The pic below is from Nadine in the Bull Mountain/Tigard area:

Chief Meteorologist Mark Nelsen