Coastal Wind Dying Down

October 13, 2016

9pm…

A cold front is moving across the Willamette Valley, and behind it wind speeds have dropped off dramatically at the coastline.  It was a pretty good storm for October out there, and at least the forecast wind speeds have verified for you folks.

Now here in the valley and metro area it’s a totally different story.  The cold front moving across the region is giving us a brief burst of gusty wind, but below what we expected in most locations.  Yes, pretty much our first metro area wind “forecast bust” of the season!  I do see McMinnville hit 48 mph.  Hillsboro & Forest Grove both hit 37 as that cold front passed through.  Should have forecast 35-45 mph gusts instead of that 40-50 mph range!

Wind will remain breezy all the way through tomorrow and in the heavy downpours tomorrow a gust of 30-35 mph is always possible.  Thunder is a possibility as well.

Today has been our wettest day since December 17th!  Hope you enjoyed it.

nora_-october

Chief Meteorologist Mark Nelsen


Windy Evening Ahead: Storm Update

October 13, 2016

3:15pm Thursday…

Update for the first storm moving over us now…more on Saturday’s system at the end of the post

RAIN  There are no watches/warnings/advisories for any kind of flooding

It’s been raining steadily, but just a gentle Pacific Northwest style rain.  Still, we’ve already picked up over an inch.

plot_rain_metro_autoplot

Since it hasn’t come down heavily there has been no flooding of course.    This evening the rain will pick up for a few hours 5-9pm and at that point we could see some blocked drains etc… for localized flooding, then the rain mainly ends after 10pm.

WIND

Wind Advisory for the western valleys (including metro area) for this evening:  Gusts 35-50 mph likely sometime between 5-10pm.

High Wind Warning for coastal strip this evening: Gusts 65-80 mph between 5-10pm.

As expected, very quiet out there this early afternoon, and no wind has even made it to the south valley yet so we’re still at least a couple hours away from a gusty south wind.  Should be plenty of power outages and a few trees down here and there through the evening once it gets going.  The wind calms down to more reasonable levels after 10-11pm.  Keep in mind that gusts between 40-50 mph two years ago in late October (with leaves on the trees) caused quite a bit of havoc.  Some of you will be getting out the candles this evening!

markoctoberpreviousstorm

 

Technical stuff for this evening:  The HRRR and NAM models keep shooting a closed and deepening surface low right up the coastline in the next 8 hours.  Looking at satellite imagery that seems overdone and I sure don’t see one.  I like the “open wave” look so the ECMWF/GFS are more likely correct.  As a result I’ve discounted the HRRR showing gusts 50-60 mph this evening.  I think 35-45 is the safest bet.  That’s not a big deal in winter, but as mentioned above a different story with the leaves on the trees and soaked ground.  There is still a perfect alignment of the isobars west-east perpendicular to the western valleys so we’re going to get a nice surge of wind.  After midnight the wind relaxes.

 

FRIDAY

Lots of showers and a showers/sunbreaks sort of day between storms.  But some of the showers could be intense and a passing rumble is possible too.

 

NOW ON TO SATURDAY’S STORM…

Two important points

  1. There is no repeat of the Columbus Day Storm coming Saturday
  2. There will be more power outages and downed trees, likely a bit more wind than tonight both inland and at the coast

Models have come into FAR better agreement now and they all are quite similar.  The GFS came much farther east and the ECMWF gave up its nasty windstorm for Oregon inland areas.

A deep area of low pressure, somewhere around 965-970 millibars central pressure, will make landfall somewhere on the Washington coastline Saturday afternoon/evening.  Past storms that make landfall that far north tend to give us a “decent” windstorm here in the valleys, but not a crippling “every 20 years” sort of windstorm.  Still, if gusts go above 50 mph in the metro area (that may happen), we’ll get even more damage than tonight.  Regardless, the coast is going to get nailed by a stronger storm on Saturday.

It was very nice to see models come together this morning…48-60 hours before the event.  That’s pretty good.  Check out the ECMWF and NAM…quite similar:

nam_satpm

ecm_satpm

A rough first guess for wind gusts in this setup would be 45-60 mph in the Portland metro area.  That said, during the past few windstorms the PDX observation site has been an overachiever compared to surrounding areas.  Remember the 67 mph gust during the December 2014 storm?

PLOT_Wind_Metro_PeakGusts_MANUAL

This could be a similar event, but someone else gets a 60 and the rest of us get 45-55 mph gusts.  That said, any gusts above 50 will be a big deal this early in the season.

Chief Meteorologist Mark Nelsen