What an interesting week for weather in the Pacific NW, a little bit of everything. At least it won’t be as cold as some parts of the Midwest, and we won’t have as much snow as the NE. The good news is that we are now ahead of rainfall for the month and snow is coming to the Cascades and Olympics. True, we are only 03” ahead for the month, but every little bit will help.
Today’s charts and sat pics also provide us with a great view of what is going on and the reasons why. Let’s start with the surface analysis chart which shows a strong ridge of high pressure (1041-1047MB) running parallel and inland from the coast from southern BC to SE Alaska. There is also a weak high (1027MB) off of LA and a weak low-pressure system (1004MB) in the Pacific headed our way. You can plainly see quite a compressed pressure gradient right over the Pacific NW and southern BC. Since winds flow from areas of higher pressure to areas of lower pressure, that’s the reason why we have this strong offshore(ENE) flow. Today’s Pac NW sat pic and the UW MM5 high-resolution chart show the flow out of the Fraser River Valley, through the northern San Juan Islands then out the Strait of JdF, building as it compresses and exits the Straits. You can also see the flow out of Stevens Pass, and then joining the flow out of the Straits. Then moving south, you can see the flow coming out of Snoqualmie Pass, down to Tacoma, out through the Chehalis Gap, and then exiting with the strongest wind just out of Grays Harbor. A great example of colder, denser air sinking and taking the path of least resistance down the pressure gradient. Notice you can also see this in the Sat Pic with a clearing where the wind is the strongest, the mouth of the Straits, and the entrance to Grays Harbor. A very nice correlation between different sources of weather information.
This gradient won’t ease much over the next 24 hours however by Sunday, we should see the winds begin to decrease as the gradient eases. As I mentioned above there will be more wind in the areas generally to the west of the gaps in the Cascades, like the Straits from Port Angeles west to Neah Bay. Then as you move south, areas like Possession Sound and Pt. Robinson southwest to Carr Inlet could see 20+ knots of ENE breeze.
Overall, the message for the weekend is to respect the cold and check conditions before you leave the dock. Then when you return to the dock remember that even in saltwater like Everett, Shilshole Bay, Elliott Bay, Commencement Bay, and Olympia freshwater flows into all those areas and being less dense than saltwater, stays on top and can then freeze in the conditions we have now. So leave the locker doors, engine compartment covers, and floorboards that allow access to thru-hulls open so warmer air can circulate in those areas. Milder conditions with rain will return on Tuesday.
Bundle up and 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)
Are we celebrating on the 15 th