Monday brought among our first Puget Sound Convergence Zones of the young fall season and Greg Johnson's camera at SkunkBayWeather.com in Hansville caught an interesting reversal in the upper level winds.
Watch as the clouds appear to make a sudden U-Turn around 20 seconds into the video:
(No word if they'll get a traffic fine for that -- I think in Washington, for U-Turns to be legal, a sign has to tell you it's OK. Come to think of it, those clouds might have been speeding too...)
The reversal happened as the general southerly winds began to collide with those west/northwest winds coming down the Strait of Juan de Fuca. Johnson's camera is in a good spot to monitor this frequent battle ground.
In this case, you can see the surface winds had already switched to the north before the start of the video and then the clouds reverse course as the winds veer at the higher altitudes.
A short time later, the clouds resumed their northerly march. (Maybe it wasn't a U-turn, but just parallel parking?)
The Convergence Zone brought a good dousing of rain to the North Sound that largely missed out on the big rains Sunday due to the rain shadow. Here is a sample of Monday's rain totals from the CoCoRahs network:
Compare that to Sunday's rain map:
The last two days illustrate how Everett and environs get about the same amount of rain per year as Seattle despite living in the Convergence Zone -- they make up for the days of extra CZ rain with less rain on the stormy rain shadow days. That spotter in West Seattle had 0.37" over the two days while South Everett/Mukilteo had about 0.33-0.42", but two very different rainy days for each spot!