There have a variety of complaints about our cloudy climate of the previous month–and it has been a bit miserable.
Yes, western Washington sometimes “enjoys” a cloudy, June gloom this time of the 12 months, as excessive strain builds over the japanese Pacific, pushing cloudy marine air as much as the Cascade crest.
Has this 12 months been significantly unhealthy? The important reply: Yes, however not by lots.
We can begin with the overall month-to-month radiation reaching the bottom in Seattle on the WSU AgWeather web site close to the UW, which solely goes again to 2012. June 2020 was the darkest June since 2012–eight years. June 2015, when excessive strain dominated our area, was far brighter. 2012 was abysmal.
Looking on the every day photo voltaic radiation numbers in Seattle, one notes some variation within the sunshine reaching the floor, with some respectable quantities in mid-month. But the primary half of June and the final week have been cloudy and darkish.
Accompanying the improved clouds was extra rain than regular, one thing evident at Sea-Tac Airport, the place there was about an inch greater than regular over the previous four weeks (see under, cyan is regular, purple is what fell into the gauge there).
Why so cloudy and darkish in June? Blame enhanced excessive strain over the japanese Pacific and decrease strain inland. But this 12 months, the sample was supercharged. Let me present you.
Here is the distinction from regular of the heights (assume strain) at round 18,000 ft (500 hPa). Heights have been a lot greater than regular (yellow/orange colours) over the japanese Pacific, however decrease than regular (blue colours) over Montana, Idaho and japanese WA/OR. Such a sample is related to greater than regular sea degree strain over the Pacific, decrease than regular strain to the east of the Cascades, and an enhanced onshore strain distinction that pushes cloudy, marine air into western Washington.
The result’s day after day we had satellite tv for pc photos that appeared like this.
Sunny in a lot as japanese WA, however darkish within the west.
Looking ahead I’ve some excellent news and unhealthy information. The excellent news is that there must be extra solar over the weekend because the above infernal sample weakens. Bad information, as a result of the sample is forecast to return subsequent week, with plenty of low clouds once more invading the west (see forecast for five AM Wednesday under).