Friday, June 12, 2015

Strong Winds Push Into the Strait of Juan de Fuca Thursday Evening

An interesting facet of our local weather is the occurrence of powerful winds in the Strait of Juan de Fuca during the warm season.  Such events are particularly strong when we transition out of a warm period.

Last night, a surge of cool marine pushed eastward in the Strait of Juan de Fuca, bringing winds gusting above 50 mph in the central and eastern Strait.

Here is a map of the max winds during the event.  51 mph at Smith Island (actually got to 55 mph there), 56 mph at Race Rocks (SW of Victoria), and 60 mph on Camano Is.  42 mph at Port Townsend.  Impressive.


Here is the plot of the maximum gusts at Smith Island this week....wind picked up a bit on Wednesday but the big spike was Thursday night (to 48 knots or 55 mph)


Our numerical models were predicting this westerly wind surge.  Here is the 12-h forecast of sustained winds (not gusts) from the UW WRF model valid at 5 PM Thursday.  The light green colors are sustained winds of 35 knots (40 mph)...a pretty good forecast.


The surge of marine air will bring a temporary respite from the above-normal temperatures, certainly today (Friday) and tomorrow (Saturday).  But we will be back into the mid-70s on Sunday and even around 80F on Monday.   And then a transition to cooler air on Tuesday...and yes...perhaps some winds in the Strait.

The weather story of Northwest summers is the battle between cool air offshore and warm air east of the Cascades.  Gaps in the mountains are the battle zones in this conflict and strong winds can result, when cold air makes the inevitable push eastward after a period of above-normal temperatures.


8 comments:

John Marshall said...

Just a correction... "winds of 35 knots (50 mph)" should be 40mph not 50.

Still, it was an impressive surge. One that got this old sailor's attention.

Jerry said...

Something similar seems to occur in the Bay Area.

The Central Valley heats up for several days and pulls marine air through the Golden Gate and around through the Sacramento River Delta, which then cools off the Central Valley and stops the marine flow. For a few days until it starts again.

But it's more associated there with cloud cover and fog than with strong winds.

It could be 65 degrees and foggy in Berkeley while being 100 degrees in bright sunshine north in Novato or south in Palo Alto.

Patrick said...

Yes, Jerry, that's the classic Bay Area weather pattern in the summer. Also microclimates form depending on the high and low spots in the mountains between the ocean and the Bay, low spots let more fog through and allows more plant growth.

elephant said...

Cliff,

I'm afraid that 60mpg gust on Camano is bogus. The location looks like my station which is sheltered and has a rate multiplier on the windspeed to match Madis average speeds. The multiplier probably exaggerated the gust. Two nearby Camano stations that are better sited reported 30/36 (1/2 mile south of me) and 34/42 on the boathouse at Cama Beach.

Tim said...

Winds gusted to 45 mph in at Vancouver Airport. Snow fell in the alpine at Gold Bridge BC (~200km NE of Vancouver)

kermitzii said...

I think we had winds of 60-80 km/hour last night in Vancouver BC

Rod said...

Hi Cliff,

I am hoping you will comment on the May Seattle precipitation that looked like July, and the June Seattle precipitation that looks like Death Valley...

--thanks,
Rod

Jim Larsen said...

I agree with Rod. Where the heck is our rain? The forecast seems to call for endless sun. I want my Washington back. :(