A Winter Storm is Approaching: In May!

This May we are experiencing winter-like levels of precipitation, winter-like increases in the snowpack, and record-breaking cool temperatures.

The only thing missing is a winter-like Pacific storm, with deep low pressure and strong winds.

Well, it won't be missing tomorrow:   a strong Pacific cyclone will make landfall on the British Columbia coast and gusty, damaging winds could batter the coast and Northwest Washington.

Even Puget Sound country will get a piece of it.

The low center will be making landfall on northern Vancouver Island at about 8 AM tomorrow (Wednesday), as shown by the predicted sea level pressure map at that time (see below).

with deep low pressure and strong winds A Winter Storm is Approaching: In May!

The solid lines are isobars, lines of constant pressure.  Where there are large gradients (large change in pressure), strong winds are expected.  Folks, there are a LOT of isobars there.

Winds will be ferocious over the ocean, with gusts near the low center reaching 50-70 mph.  

I hope no Alaska cruise ships will be traversing the region tomorrow morning.  It might dampen the appetites of the passengers.😊

Take a look at the predicted wind gusts at 5 AM Wednesday.  Over 50 mph over the Pacific and across portions of Northwest Washington.  Going to be very windy in the San Juans, Victoria, and the eastern Strait of Juan de Fuca.

From City of Seattle WindWatch

And then as the low center moves eastward across southern BC, strong winds will surge eastward into the Strait of Juan de Fuca and winds will gust around Puget Sound (see the forecast wins at 2 PM Wednesday)

Seattle WindWatch

The latest wind forecasts over Seattle indicate the wind potential for Wednesday morning and afternoon (see below).  The red line is from the UW high-resolution forecast system...and is usually the most skillful.  It is predicting gusts exceeding 40 mph in exposed locations over Seattle.  With leaves on the trees, expect some branches to fall.

Seattle WindWatch
 
How usual is it to get such an event in May?  

Quite unusual.  This figure below shows the forecast pressures at 11 PM tonight at around 800 meters above sea level (solid line) as well as the standardized anomalies of the winds at that level (colors).  Such anomalies from climatological conditions are expressed in standard deviations and are quantitative measures of how usual a weather event is.   Impressively, the wind anomalies climb to 5 standard deviations, which means unprecedented in the 30-year period used in the calculations.  



Bottom line:  an unusually strong storm in an unusually cool, wet spring.


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