Windiest October Day Since 1967: Storm Wrap-Up

October 15, 2016

6pm Saturday…

The wind warnings are all now cancelled in Oregon…as the wind has subsided.  Take a look at that…the highest October wind gust we’ve seen here since a 70 mph gust in 1967.  There was a gust to 52 mph on different wind equipment late October 1994, but that’s the problem with comparing historical windspeeds.  It’s possible either this or that one was really the higher gust, but for sure it’s fair to say this is one of the two windiest October days I’ve seen in my lifetime here!   That shows you how rare an October windstorm is in the valleys.

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Other peak metro gusts…

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Northern Willamette Valley…

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A few things that stick out:

This was just an average “windstorm” for any winter here in the I-5 corridor EXCEPT that it happened in mid October!  44,000 PGE power outages at the peak

This was almost a perfect windstorm forecast for the metro area, both timing and speeds.  Last night I said 45-55 mph, then dropped it to 40-50 mph at the last minute.  That’s fine because only 3 of 7 metro area official reports made it to 50 mph.  Very happy with the metro forecast.

COASTAL FORECAST BUST

Wow, this one was way off.  Tillamook and Astoria had lighter gusts than Portland!  It was widely forecast and promoted as a major storm for the Oregon Coast, even if it was wintertime.  Not even close!

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Coastal cities were generally in the 50-65 mph range.  We forecast 70-90, or even 70-100.  Sure, that exposed tower out at Barview Jetty in Garibaldi hit 77, but that’s about it.  The two big speeds in the 80s are up above 1,000′.  By the way, Mary’s Peak west of Corvallis went over 100 mph, but that’s not unusual during a windstorm…that’s in the mountains.

What happened?  The low tracked farther offshore, thus the south to north gradient was far weaker along the coastline.  Check out the 6pm forecast (right now) from this morning’s WRF-GFS run:

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Pressure should be under 970 millibars on that northwest section of the Olympic Peninsula.  Instead the pressure is over 10 millibars higher!  981 mb right now at Forks, WA.  That’s a huge difference.  And check out the low well offshore, shown by the radar at Ocean Shores…

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Right now there is an 18 millibar pressure gradient from Coos Bay to Forks.  The forecast was for 28 millibars!

There was also that strong hing on the gradient field that the wind might be much more closely confined to the low center than normal…leftovers from it’s tropical days?  Probably not but something to think about.

This storm stayed farther offshore and made a landfall farther north than expected = weaker wind at the coastline.

Chief Meteorologist Mark Nelsen

 


3pm Update: 53 mph in Portland

October 15, 2016

Our windstorm is likely peaking just about now.  Within the past hour we’ve seen a gust to 53 mph at PDX, 49 in the West Hills, 52 in Salem, & 51 in Hillsboro.

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This should be the peak of the storm based on the low movement and pressure gradients, but gusts between 45-55 mph will continue for another hour or so and then die down.

Looks like 44,000 PGE customers currently out, which is better than the last October storm which had lower windspeeds in 2014.

The coastal speeds have been well below what we forecast in most locations and quite similar to Thursday’s storm.  Newport only gusted to 55 and Astoria 51 (so far).  Garibaldi reached 77.

Chief Meteorologist Mark Nelsen


1pm Storm Update

October 15, 2016

The timing for the windstorm along the coast and (relatively) minor windstorm in the valleys is on track.  The low pressure center appears to be out there west of Tillamook still deepening and headed north quickly.  This analysis by the HRRR model puts it around 974mb.  Generally with these storms the surge of south wind arrives about when the low crosses your latitude.  Basically as it “goes by” to your west the wind arrives.lowpressure_1pm

RANT:

We could have REALLY used an Oregon Coastal Radar this morning to figure out exactly where the low was!  There is no coverage off the central Oregon coastline…the only part of the USA coastline left “radarless”.  But that’s a political, not NWS solution = lots of $$$.  Hard to believe NOAA has a major facility in Newport and they don’t even have radar coverage.

RANT OVER…

I’m tracking wind the old-fashioned way here in the weather center:

wind

So far the wind is underachieving on the coast.  At 1pm gusts have barely reached 60 mph on the central coast.  A gust to 58 at Newport.  If it doesn’t bump up dramatically in the next hour, it’s possible the low is just far enough offshore (it’s quite a compact storm) that the huge wind stays just offshore…we’ll see.

Our forecast is for gusts 70-90mph still so we’ll see how that works out.

Inland the south wind has been blowing for a few hours in the valley with gusts into the low 40s at Eugene and Salem.  That tells me gusts 40+ are looking likely in the metro area in the next 3 hours.  We are closer to the low center as it moves north and the pressure gradient is tighter up here.  Still expecting widespread gusts 40-50 mph metro area between now and 4pm.  Expect lots of outages and trees down.

And one last time…

There is not a “severe” windstorm coming to the metro area and also not Columbus Day Storm II.   But a very windy afternoon!

Chief Meteorologist Mark Nelsen