Another windstorm will hit the Northwest on Thursday

Mother nature is throwing everything in her cupboard against us this week.   We had the first major Pacific cyclone/windstorm, lots of snow in the mountains, heavy mountain rains, a downslope windstorm event on the Olympics, and an EF1-2 tornado.   Meteorological heaven for those who like a good storm.

But the strong storms are not over yet, and Thursday will bring another strong Pacific cyclone to our coast, with strong winds and power outages for many. 

Here are the latest forecasts from the UW WRF model.  We are close enough in time that this evolution should be fairly accurate (and the spread of the ensemble is not that great now).

Let's start with the forecast sea level pressure map at 1 AM Thursday.  A 991 hPa low center is found offshore, with a strong pressure gradient (large change in pressure with distance) off the Northwest Coast.  Thus, strong coastal winds (probably gusting to 30-60 knots) would be in place over the water at that time.

The storm, moving northeast makes landfall on Vancouver Island, and is over southeast BC by 1 PM Thursday afternoon (see below).  The region of strong pressure gradient is over western WA at this time, and particularly NW WA.  Winds would be revving up over inland western WA by this time, peaking a few hours later over Puget Sound.

Let me show you high-resolution forecasts of the surface winds. At 4 AM, wind gusts will have reached 50-60 knots, along the coast, and nearly as high near Victoria and the southern San Juans.  Also note a strong Olympic mountain wave, with strong flow descending the northern slopes of the Olympics.  Deja vu all over again.

By 10 AM (18 UTC), winds rev up in Puget Sound (gusting to 30- 40 knots), with big winds remaining along the coast and San Juans.

 Then the final stage of the wind action, as the low moves by to the northeast, a strong onshore pressure gradient will develop and a westerly wind surge will occur in the Strait of Juan de Fuca (see map for 4 PM on Thursday).   If you were planning a ride on the Victoria Clipper between Seattle and Victoria tomorrow afternoon, bring plenty of Dramamine--it will be a very rough ride.

This event probably won't be more intense that last Friday's windstorm over Puget Sound, but potentially stronger over NW WA and the coast.  There is some variability in the exact landfall position, and  small error could have a big impact on the winds, so keep watching the forecasts. Make sure your batteries are fresh, your barbecue has gas, and your smarphone is charged.

from Cliff Mass Weather and Climate Blog https://ift.tt/2CmvNpc