High Wind Watch Cancelled; More Typical “Windstorm” Instead

March 12, 2016

10pm Saturday

I’m not working today or tomorrow, but after that dramatic post yesterday I figure I should provide some sort of update.

All evening models are in  and all (except NAM) agree on a landfalling surface low on the Olympic Peninsula tomorrow afternoon.  They are a LITTLE bit weaker than 24 hours ago.  As a result of no “huge wind” solutions on models (closer or deeper low), the NWS cancelled the High Wind Warning and went with a Wind Advisory instead here in the valleys.  A Wind Advisory covers gusts 39-58 mph, which means just about every wind event we get that gives us outages and tree damage.  It takes a lot to get widespread gusts above 58 mph in our climate.

HIGHLIGHTS

  • Gusty wind arrives on the coast mid/late Sunday morning.  Gusts 65-75 mph are likely, especially north coastline
  • The western valleys should experience wind ON AVERAGE similar to what we saw about 10 days ago or possibly a little stronger.  A minor windstorm with a bunch of power outages (maybe 15,000 PGE customers?) and some trees down. Gusts 35-45 mph with a few spots to 50 mph for us.  If I were a betting man, I’d say a gust 45-50 mph at PDX midday or early afternoon.
  • We do not expect a big historic windstorm Sunday.  That’s one where 80-150,000 customers lose power, but you’ll definitely hear it blowing and see some effects.
  • Gusty south wind blows hardest in the valleys 11am-3pm.  It may arrive suddenly in that time just before lunch as well.

What has changed in 24 hours?…not too much, but a subtle shift towards slightly weaker low pressure and now consistent landfall location.  As a result gradients appear weaker inland.  For Eugene to Olympia, this is what models are showing with 00z runs:

RGEM=12, WRF-GFS=10, ECMWF=14, NAM-MM5=20!

That’s quite a range of solutions isn’t it?  Assuming models are handling the depth of the low correctly, we should escape a big windstorm here.  Stronger wind to the north and west of us closer to the surface low.

Here is the WRF-GFS at 1pm:

wrf_1pm

Notice the gradient “stacking” is not too tight in the Willamette Valley.  Compare that with the gradients last March 15th’s storm that gave us gusts 45-55 mph…not as tight.

The NAM-MM5 has continued to be stronger and farther south…3pm tomorrow:

nam_3pm

That’s a huge windstorm up in SW Washington!

Note the GFS ensemble low locations (21 of them!) all keeping the low farther north, not down south like the NAM when it makes landfall, part of the reason I’m not real excited about following that NAM solution:

gefs_slp_lows_conus_7

Happy low pressure tracking tomorrow morning!

Chief Meteorologist Mark Nelsen