Windstorm Wrap Up

December 11, 2014

Now TODAY was a fun weather day for the meteorologists!  But it’ll be nice to relax after work now that the storm has moved on to the north.

First, a bit of a buried headline is the “heat”.  You just enjoyed the warmest December day since…the 1995 windstorm day!


Notice Vancouver was just as warm.

On to the wind gusts.  Here are the numbers:

PLOT_Wind_Metro_PeakGusts_MANUAL2 PLOT_Wind_Metro_PeakGusts_MANUAL

Hillsboro, Aurora, & McMinnville reported those numbers and then went offline due to a power outage.  So it’s possible the numbers were higher.

Let’s talk about what went right and what didn’t turn out as well:


TIMING:  Wow, models were right on!  Peak wind gusts were right about the time we expected.  The winds picked up and dropped off quickly as expected.

DEPTH OF LOW:  Looks like low pressure center bottomed out somewhere near 973 millibars according to NWS.  That’s close enough to model forecasts, quite similar to WRF-GFS for sure.

TRACK:  It took until 24 hours ahead of time for models to pull it together, but they all showed a reasonably accurate path. The low just scraped by the NW tip of Washington and is running into Vancouver Island right now.

MODEL FORECAST WIND:  The WRF-GFS did really well, showing the higher speeds on this morning’s run.


MODELS:  GFS was the first to latch onto the correct track…there, I said it.  The ECMWF played catch-up until about 48 hours ahead of time.  The NAM was terrible until the last 12 hours…reminder to ignore it in the future.  GEM kept shoving the storm inland and didn’t correct itself even 24 hours ahead of time.

COAST FORECAST:  A total miss here.  It was nothing more than an average winter storm at the beaches, and definitely not a major storm as was advertised.  Peak gusts were almost all below 70 mph.  I saw a 79 at Newport Jetty and 89 at Sea Lion Caves, but that 2nd one was even out of our viewing area.  Astoria only hit 56!  Anyone on the coastline north of Lincoln City is thinking “that was it???”

INLAND WIND FORECAST:  I first said 45-60 mph, then yesterday said 45-55 mph for metro area airport locations (official sites).  Then this morning leaned more to 50-55 mph on my 10am posting.  For much of the area that forecast was fine, but obviously we had some gusts around 60 mph.  PDX airport seems to be a bit of an outlier at 67 mph, similar to that extra strong 55 mph gust last February when everyone else was much lower.    The NWS first had gusts 55-65 mph yesterday (a good call!) then lowered it to around 50 (local gusts to 60) for the metro area in this morning’s forecast and tweets.  Close enough.

SOCIAL MEDIA:  It’s a scary medium!  One where a bad fact can spread across the globe in minutes.  One bit of info that went out said PDX’s peak gust was the strongest since 1971.  Within minutes that was all over Twitter, and I saw a Weather Channel tweet about it!  The 1981 storm had a stronger gust.

How did this windstorm rank?

For the Portland metro area ON AVERAGE I would say it was similar to the December 2006 storm when you compare damage and power outages.  Looks like in some locations (PDX) it was stronger, but in 2006 we had far more power outages.  I noticed today that Multnomah county had far fewer outages than Washington county.  For whatever reason there was more impact central/westside than eastside and Clackamas county.  Clark county was hit hard too.  January 2000 was a similar storm to what we saw this afternoon.

The December 1995 was far stronger in our area.  Several reports of 70-80 mph gusts in parts of the West Hills.  Here’s a chart showing peak gusts at PDX compared to PGE outages.  You can see how much more widespread the 2006 & 1995 events were:


It’s tough to compare these windstorms speed-wise because three different instruments have been used at PDX since the 1980s.  Up until 1994, the sensor at PDX was an instantaneous gust measurement, but when ASOS units were installed in 1995, the gust had to register for 5 seconds!  So recorded wind speeds went down for 11 years.  Basically it was harder to get high wind speeds.  All three storms on that chart above used the 5 second gust.  Then right after the 2006 storm new sonic anemometers replaced those units and now it’s a 3 second gust.  See how comparing the speeds is a bit of apples vs. oranges?  Wolf Read has an excellent piece of work about this issue on his webpage.

During the December 1995 storm, BOTH units were operating at PDX.  The new “official” gust was the 62 mph you see above.  But the old unit read 74 mph with instantaneous gust.  You can see the difference!

What are YOUR thoughts about the storm?

Chief Meteorologist Mark Nelsen

6:45pm: Storm Dying Down

December 11, 2014

Real busy, but I’ll blog again in the next couple hours to wrap things up.

PGE outages appear to have peaked around 85,000, which is similar to the October storm but far short of previous windstorms over the last 20 years.  More on that later.

Wind is dying down slowly, but the speeds should really drop off the next two hours.


Portland Airport had a peak gust of 67 mph, which is the strongest in that location since 1971, 1981, 1995, or 2000…depending on how you measure it and who said it!  Ahhh, social media…  That’s a meteorologically-loaded topic!  Should be a fun one to discuss on the blog on the post later.

Chief Meteorologist Mark Nelsen

4pm Update: Peak of Storm Now

December 11, 2014

NWS reports a peak gust of 62 mph at PDX Airport.  That’s the strongest wind gust we’ve seen in that location since the January 2000 windstorm.  Some other very strong wind gusts out there at this hour.  This is what I have so far for the northern Willamette Valley:

PLOT_Wind_Metro_PeakGusts_MANUAL2 PLOT_Wind_Metro_PeakGusts_MANUAL

Some bad news.  Apparently the airport (ASOS) weather sensors do not have backup power so Hillsboro, Aurora, and McMinville stopped reporting.  That’s pretty bad for a wind sensor to stop reading in the middle of the storm!  Can’t they just buy a UPS backup?  So we don’t know for now if those locations were windier than the 3pm observations.

This wind is big-time overachieving for the gradient.  There is only a 5 millibar gradient from Eugene to Portland and 9 millibars from Eugene to Olympia.  Most of the time that would give us gusts to…20 or so miles per hour.  The speed of the low pressure and strong upper level winds surfacing are definitely more important this time around.

Another note, the outage numbers don’t appear to reflect widespread 60+ mph gusts.  Still only around 60,000 PGE customers out.  During the 2006 storm with “lighter” wind, there were 200,000+!  I have a feeling that we’re just seeing scattered spots with strong wind surfacing instead of a widespread damaging wind.

Nevertheless, a crazy afternoon!

Chief Meteorologist Mark Nelsen

3pm: Wind Hitting Hard

December 11, 2014

Stuff is getting real now!

Some big gusts out there in the last 30 minutes:  61 at Aurora and McMinnville airports!  49 at Forest Grove, 69 on Chehalem Mtn.  I see a 55mph in a neighborhood in Tigard.  So we’re getting random strong gusts surfacing at times.  Out on Mt. Hebo at 3,000′ a gust to 130 mph too.

Lots of damage reports coming into the newsroom as well.  And PGE power outages suddenly jumped up to around 20,000 customers.

Coast still underperforming compared to forecasts.

Hang on the next 2-3 hours during the peak of the wind…

Chief Meteorologist Mark Nelsen

2pm Update: Windstorm Beginning In Valley

December 11, 2014

Gust to 52 mph in the past hour at Eugene and 47 mph at Salem.  Corvallis hit 48 mph.  Upper level winds are also beginning to surface in some spots that don’t normally get strong wind along the Cascade foothills. I’m surprised to see within the past half hour Scotts Mills (relatively protected location) hit 46 mph and a 48 mph up the hill from Estacada on the way to Colton.

Note the high-tech wind gust tracking sheet.


Coastal winds (so far) have been much lower than I expected.  I see a 72 on the Yaquina Bay Bridge otherwise just a standard coastal windstorm so far…

Low pressure center is due west of Tillamook and tracking north.

Real strong wind in central/northeast Oregon too.  The Bend/Redmond area saw widespread gusts in the 50-65 mph range and Joseph (NE) hit 75 mph about an hour ago.  66 mph gusts at Shaniko and Lexington too.  Looks like everyone is getting in on the action!

Storm Day: 10am Update

December 11, 2014


Everything is on track for strong/damaging winds to arrive in the next 2 hours on the central coastline of Oregon and into the Willamette Valley soon after.  Hold on this afternoon!

Morning models are in and (surprise!) every single one pretty much matches what we are seeing on satellite imagery which is very close to what has been advertised the past 24 hours.

Low pressure is tracking north along the coastline and strong south wind fills in behind the low as it moves north.  It appears to be a little faster than my previous forecast…by about 2 hours.

  • Wind arrives around Newport/Florence around Noon
  • Wind arrives in the southern Willamette Valley 1-2pm
  • Wind arrives Salem by 2-3pm
  • Wind arrives in Portland metro area 3-4pm, just east wind until that time.
  • Peak gusts will be within 3 hours of wind arrival all these areas…it’s a fast-moving system
  • By 9pm it’ll be back to just “breezy” and then mainly calm by midnight

I haven’t changed my peak gust forecast of 75-90 mph on the coastline and 45-55 mph in the valley.  This isn’t a major windstorm by any means in the interior valleys, but enough to cause lots of outages and trees down.

That said, I’m leaning towards the upper end on the valley wind speeds.  I’m thinking we’ll see gusts at metro area airports (official locations) in the 50-55 mph range.  THIS IS A BIT STRONGER THAN WHAT WE SAW IN OCTOBER.  Maybe I should have stayed with the 45-60 mph gusts I first forecast two days ago.  Why?

The WRF-GFS came it a bit stronger with wind gusts in the valley.  Plus it appears there will be plenty of sunbreaks, maybe even just partly cloudy, as the strong wind arrives.  Temperatures will jump into the lower (or mid?) 60s for an hour or so when that happens.  Look at all of the significant windstorms here that occur during the day and you’ll see the high temp is always very warm.  Warmer temps at the surface add more instability.  That allows stronger winds above to surface down where we live more easily.

You can see the progression of the wind very nicely on the HRRR model below at Noon.  Note wind gusts forecast speed is in knots…multiply by 1.15 for mph:


2pm…wind arriving at Albany and Salem


4pm…rocking and rolling at this point in the metro area.  Watch out for downed trees and/or flying debris during the evening commute.


10pm…down to some southerly breezes with lots of us out of power!


These are from WeatherBell, a private organization that produces some beautiful weather maps!  It’s a subscription site, but worth every penny if you are a weather geek like me.  If your boss pays for it…even better!

The forecasting is done and now we just sit back and wait for the wind reports to roll in…

We have more newscasts on FOX12/PDXTV than any other news organization in Portland.  So we’ll be on FOX12 from 5-7pm, PDX-TV 8-10pm, and FOX12 again from 10-11:30pm.  During that time of course we’ll be keeping you updated on-air.

Since we’re not ALWAYS on (although it seems like it in the evening), remember we’re on Facebook and Twitter as FOX12WEATHER and of course right here on the “old-style” FOX12 WEATHER BLOG.  There are other weather groups on Facebook in the Portland area, not run by me or endorsed by FOX12, but you’re welcome to join them too of course.  What they do is their own business so don’t come to me complaining about something over there.

I’ve opened the comments down below…but for the love of meteorology…please stop acting like children!

Chief Meteorologist Mark Nelsen