I know, it’s not officially fall yet however it has become decidedly cooler in the evening hours. There is plenty of sailing action this weekend and except for the central and eastern Strait of JdF tonight and tomorrow night, it will once again be a fairly light air weekend.
The surface charts, upper air charts, and Satellite pictures give us a fairly clear overview of what will happen this weekend. We still have that low sitting on the other side of the mountains with a weak ridge of high pressure just offshore. This combination will continue to drive a weak onshore flow down the Straits. Offshore on the surface charts you’ll see a large but very weak low-pressure system (1008mb) with an attached cold front. This system also shows up very nicely on the satellite picture. This will move over the area late Saturday night and into Sunday morning. It won’t bring much if any moisture with it unless you’re hiking in the Cascades.
Sept 6 500MB 
Sept 6 Surface Analysis 
September 7 Surface Forecast 
Sept 8 500MB 
Sept 8 Surface Forecast 
Sept 10 Surface Forecast
The Saturday surface forecast chart shows very clearly the reason we’ll be having light air as there is almost no pressure gradient from the Rockies to well offshore in the Pacific and as that frontal system hits the coastal buffer zone it will weaken and just go away.
The Sunday surface forecast chart is much more interesting in that from 20N to 60N and east of 140W we have SEVEN (7) low-pressure systems including the rapidly weakening Hurricane Juliette. Unfortunately, even with all these systems there is still no pressure gradient over the Salish Sea.
There was also a lot of discussion about the new “Blob” that has been forming off of the West Coast which, if it continues on its current trajectory, will have a serious impact on our area which is still recovering from the last “Blob” which was forming in September of 2014. The current “Blob” is much larger and much further along in its development. The reason why is what we have been complaining about all summer; no “normal” Pacific High and with no high, lows have been able to push across keeping the air mass offshore stagnant allowing for more heating of the ocean. The other feature contributing to this is the lack of a jet stream to move systems across and stir up the atmosphere. Today’s 500mb chart at least shows the jet stream trying to make its way south however the 8 September 500mb forecast chart shows yet another cut-off low-pressure system forming just off our coast which will slow the advance of the jet stream as it tries to get south. Definitely, something to watch.
Speaking of interesting things to watch, keep an eye on the Atlantic Basin this coming week as there is the potential for three more hurricanes to form with one of them setting up to be another major storm impacting the Caribbean and the East Coast.
Have a great weekend.
Ed. Note: Bruce is taking some time off to travel Italy and the French wine regions for the month of September. This coincides (purely accidentally) with the grape harvesting season. Rumor has it he’ll be chartering a powerboat. Yes, good Salish readers, we’ve got nothing really against powerboats. If anyone with skills wants to try a weekend weather forecast while he’s gone, please get in touch.
Bruce has raced and cruised the Pacific Northwest his entire life. He earned a Bachelor’s of Science from the University of Washington in Biological Oceanography and learned meteorology “to keep from getting kicked around on the race course.” Bruce spent nearly two decades as Associate Publisher for Northwest Yachting Magazine, retiring in mid-2015, and was the chairman of the board of trustees for the Northwest Marine Trade Association in 2014. (photo of Bruce driving Playstation is a bit dated, but cool)