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.

JoeRWind_PeakGustPDX

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.

Mark_PGE_PowerOutages

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.

PLOT_Wind_Metro_PeakGusts_MANUAL2

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.

PLOT_Wind_Metro_PeakGusts_MANUAL1

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


Strongest April Windstorm in 50 Years Arriving

April 7, 2017

8:10am

Wow!  That accelerated quickly….

Our models were correct and we have a major spring windstorm moving into the valley this morning.  Wind gusts are looking more like the strong models showed.  Hold on…it’s going to be a wild ride the next few hours.

The initial burst of wind has hit Portland…PDX has hit 53 mph, and Salem has a gust to 60.  54 at McMinnville.  I see a gust to 78 mph on the West Hills, a speed I haven’t seen at that location in at least 10 years.  A weather station on Chehalem Mtn. near Newberg has recorded a gust to 73 mph.

Widespread power outages have occurred of course.  I see PGE already reporting almost 50,000 out.  This is going to be an April storm to remember.

Satellite imagery shows the surface low just west of Tillamook so peak wind gusts should be between now at noon.

8:34am…Okay, generator is on…power went out partway through blog post.  Looks like up to 80,000 PGE customers now and a 56 mph gust at PDX.  61 at Hillsboro!  Wow, quite a storm.

Chief Meteorologist Mark Nelsen