First Storm of the Season Thursday

October 11, 2016

6pm Tuesday…

The NWS has issued a High Wind Watch for the Coast and Coast Range this evening.  That’s for the first system coming onshore Thursday.

markwarnings_high-wind

There is some disagreement on the details with this first system, and the following three I’m tracking for Friday, Saturday, & Tuesday.  That’s partly due to the fast-moving storms and a powerful Pacific Jet Stream.  It also doesn’t help that a large amount of energy is getting injected into the westerly flow by a Super Typhoon east of Japan.  Models have trouble handling those.

The plan for Thursday is a surface low tracking north along the coast, but some models are more intense than others.  The preferred ECMWF model has a surface low farther offshore. Based on that I could see gusts 55-70 mph gusts on the coast Thursday evening and 35-45 mph in the western valleys Thursday night and Friday A.M.  Those inland winds aren’t crazy strong for winter, but those speeds can down some trees this time of year due to the leaves still on many of them.  We have seen that the past couple of Octobers.  That’s storm #1.  There will be a LOT of rain with this system too since it’ll have subtropical moisture with it; hopefully we can avoid flooding since it’s the first huge soaking of the season.  We’ll see.  Check out our RPM rain totals:

rpm_12km_precip_nwor

What about Saturday?

Just east of Japan, now “Super-Typhoon” Songda is as intense as Hurricane Matthew was last week…150 mph winds!  It is forecast to fall apart and turn “extra-tropical”.  It’ll travel thousands of miles across the Pacific the next 3 days and end up on our doorstep Saturday as it develops into a massive mid-latitude low pressure system.

marktropical_typhoonpacific

Just so we’re all on the same page… A TYPHOON (SONGDA) WILL NOT BE HITTING THE PACIFIC NORTHWEST ON SATURDAY

At this point the ECMWF, GEM, & GFS models all have about a 956-960 mb low pressure center (same depth as Columbus Day Storm) tracking southwest to northeast somewhere near the Pacific Northwest coastline on Saturday.  The GEM and GFS have the low farther offshore making landfall up around the northern tip of Vancouver Island.  This track brings damaging wind to the coast but generally not inland…it’s too far away.  For the hardcore weather geeks, here are some interesting products off the WeatherBELL site.  They have an excellent array of maps and I highly suggest you get a subscription if you go through as many maps/models as I do!

The GEFS ensembles from the 18run today showing the low pressure center Saturday afternoon on the control run,

 

gefs_operational_satpm

all 21 low pressure center location & depth,


gefs_alllows

and the lowest pressure of any ensemble member (the deepest low),

gefs_slp_min_nepac_19

Yes, that is a 945-950 mb low much closer to the coast.  Interesting to see how many possibilities are out there.

The ECMWF has the low pressure center much closer to us and the storm comes from a more southerly latitude; that’s potentially a far more damaging hit that could bring high winds inland.  We’ll see how things shake out the next three days.

The Columbus Day Storm was much closer to the coast than anything forecast for Saturday.  It moved quickly and was still strengthening as it moved north.  Those three factors are what make that storm the standard we measure all other storms by.  By the way, here are the peak speeds from that storm…

markcolumbusdaystormpeakgusts

Can you imagine the damage 90+ mph wind gusts could cause nowadays?

Chief Meteorologist Mark Nelsen