Evening Model Runs…More Interesting

March 11, 2016

10pm Friday…

An interesting evening in the weather center hitting REFRESH numerous times to get the latest maps/models.  Here is the latest:

MarkWarnings_High Wind

HIGHLIGHTS

  • High Wind Watch is up for all of Western Oregon north of Eugene
  • Damaging wind is POSSIBLE Sunday, but not a “done deal” as of this evening
  • The setup is quite “good” if you want the strongest southerly windstorm of the season.  Bad if you don’t like power outages and downed trees
  • Big question still:  Is this a regular “gusts 35-45 mph” storm or “gusts 45-65 mph” (storm of the season) storm for the lowlands.  Right now I’m thinking the first is just about guaranteed, but it might be higher.
  • Confidence on timing = HIGH  Sometime midday/PM Sunday
  • Confidence on damaging wind event in metro area = MODERATE for now

 

MODEL THOUGHTS

All 00z models are in except ECMWF.  That’s the one model that was farthest west (offshore) this morning.  If it makes a significant move closer to the coastline Sunday my confidence on a damaging wind event will go up. (Edit at 10:15pm)  Well, it did move farther east, so now models are much closer together.  The 00z ECMWF has the low reaching the western mouth of Juan de Fuca strait at 980mb.  I see a 12 mb pressure gradient from Eugene to Olympia, which isn’t a big windstorm, but plenty windy!

ecmwf_mslp_m_nw_9

All these models have at least some sort of wind event for the metro area and valleys.  WRF-GFS was a little weaker for us and farther offshore, giving us 13 millibars EUG-OLM. That’s like the ECMWF

slp.45.0000

That’s not major storm material, but widespread gusts 40-50 mph.  Of course in that case the abnormally high PDX readings the past two years mean a 55-58 could be seen there I suppose.  Check out the track I plotted over Wolf Read’s analysis of past “classic” windstorm tracks.  The WRF track is the thick yellow highlighter:

Tracks_plusWRFGFS

The NAM-MM5 was very strong (image below)…that’s a windstorm for us with the low much closer, making landfall around Long Beach instead of up around Forks like the other models.  21 millibars from Eugene to Olympia with the real damaging wind up in SW Washington.

wgsfc.45.0000

RGEM (Canadian) looked almost exactly the same as the WRF-GFS, in fact the lowest central pressure was around 980 mb. as well.

00zRGEM

It is interesting (and helpful if you want a powerful storm) the low is deepening on all models as it passes by.  That’s very important for strong wind.

These storms are always so tough to forecast and each one is slightly different.  For example the Inauguration Day Storm in January 1993 took a similar path and was of similar strength to what the WRF forecasts yet left gusts only in the 40-50 mph range in the metro area.

More updates the next 36 hours if this impending storm holds together!

Chief Meteorologist Mark Nelsen

 

 


High Wind Watch For All of NW Oregon/SW Washington

March 11, 2016

4pm Friday…

The Portland and Seattle NWS offices just decided to issue a High Wind Watch for ALL of NW Oregon and Western Washington.  That includes all the cities in the I-5 corridor from Eugene to Bellingham.  That’s around 5 million people under that watch!  We haven’t seen one of those since mid-December.

MarkPromo_HD_HighWind_Coast

A High Wind WATCH means conditions MAY be right for damaging southerly wind on Sunday in our area.  That’s a HUGE (or is it UGE?) question mark right now.  Thus a “Watch” instead of a “Warning”.  High Wind Watch/Warning criteria means gusts to 58 mph or higher…that is a real windstorm as opposed to these weaker storms we’ve seen much of this cool season that have involved Wind Advisories.  That’s the 35-55 mph stuff.

I’ll reserve any deep thoughts until after the evening model runs tonight for two reasons:

  1.  It’s way early…we’re talking about something almost 48 hours away
  2. Several models (including the reliable ECMWF and latest GFS) show no such windstorm
  3. Yet the NAM, GEM, and earlier GFS run looked real stormy.

 

So, there you have it:  We may or may not see strong wind Sunday.  It’s too early to know whether a real windstorm is on the way…we’ll be WATCHING the maps/models closely this evening and again tomorrow morning & evening.  We have plenty of time to see if models come together on a common solution.

Chief Meteorologist Mark Nelsen


Quick Look: Windstorm or No Windstorm Sunday?

March 11, 2016

Have to get to work early today for something else, but my eye is sure drawn to this…

Both the WRF-GFS & NAM-MM5 forecast a significant windstorm in the valleys Sunday midday/afternoon.   Deepening surface low moves inland over Washington, isobars are perfectly aligned, and 15-20 millibar pressure difference Eugene to Olympia.  Wow, that’s like what we saw in December 2014 or stronger.  50kt gusts forecast over metro area at the surface.

slp.58.0000

Yet…ECMWF says WHOA!,  the low is headed into Vancouver Island instead and it’s just regular breezy here.  In fact none of its ensemble members from last night, or the operational run this morning have the low close by.

eps_slp_lows_nw_12

It’s an epic model fight but one we’ll be watching VERY closely…more later today.

Chief Meteorologist Mark Nelsen