The weather is definitely getting more interesting the closer we get to the end of the year, the shortest day of the year and the first day of winter. Naturally, we’ll have a celebration of the Winter Solstice on the 21st at 1423 hrs because the days will start getting longer from that point on.
The weather charts for today offer a very interesting picture of what’s to come for the weekend. While today’s analysis shows a very impressive low-pressure system off our coast with a long cold front attached, it won’t have much effect on the central or south Sound. There are two reasons for this: the first is that persistent high-pressure system (1036MB) just east of the Cascades and the second is our coastal buffer zone which will once again have a deleterious effect on any frontal system as it hits the coast. That high-pressure system is the one that has been responsible for bringing us the coldest temperatures we have seen so far this Fall. Since it is on the other side of the mountains it creates an offshore flow that brings cold air from the interior of BC and forces it through the mountain passes into the Puget Sound area. This is going to slowly change.
If you look at the surface forecast chart for tomorrow morning you can see that front from today has already been significantly degraded and our guardian high-pressure system has been weakened to 1032MB and pushed to the southeast. This will open the door for that next frontal system to come ashore late Saturday and into Sunday morning. You will also notice that these low-pressure systems instead of being sent in a northerly path are now on a more northeasterly path. Eventually, this will become more east-northeasterly as the week goes on, allowing more moisture into our area.
Click any image to enlarge.
December 7 500MB 
December 7 Surface Analysis 
December 8 Surface Forecast 
December 9 500MB 
December 9 Surface Forecast 
December 10 Surface Forecast 
December 11 Surface Forecast
What effect will this have on the breeze for this weekend? The strongest breeze today(20-30 knots)will be the pre-frontal south-easterlies in the coastal waters and the eastern and western parts of the Strait of JdF. There will be a brief respite for those areas on Saturday morning and into mid-afternoon at which point the winds in advance of the next front will once again pick up in those same areas. The winds in the central and south Soundwill be 10-15 knots from the southeast on Saturday morning becoming lighter as the day goes on.
After midnight on Saturday, the pre-frontal breeze will pick up significantly along the north coast and the eastern part of the Straits as in 25-35 knots of southeasterly. This will ease as the front passes through late Sunday afternoon. The central Sound will see 10-15 knots of southeasterly easing around mid-afternoon while the south Sound will see generally lighter conditions all day.
The next front which will bring more lowland rain and mountain snow will start to show up on Tuesday.
Enjoy the weekend!
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)
Thanks Bruce,your morphing into a great weather man