It’s been a great week with relatively nice weather and a stellar Seattle Boat Show. And a big thank you to all of you that attended my talks at the Show. That was fun.
Today’s surface analysis chart shows a couple of key features we discussed this week at the show. The first being the frontal system that will move over us today attached to a weak 995MB Low with a weaker 996MB Low immediately to the southwest. The latter of these will move onshore and be broken up by our coastal buffer zone.
The other key feature is that relatively innocuous looking low-pressure system(1005MB) in the Pacific off the coast of California. This bears watching because of two indicators on the chart. The first being how far it will move in 24 hours as designated by the arrow ending in an X. Immediately above the X is 83 which means that this low is expected to significantly intensify by dropping to 983MB, a whopping 22MB drop in pressure. As you can see from the 24-hour surface forecast chart, this low will become rounder, stronger, with a much better-defined front. It’s not a large low-pressure system but it will pack a punch bringing significant rainfall(5”-8”) to the coastal areas from San Francisco south to San Diego and to the burn areas that have no vegetation to anchor the slopes. It will also bring as much as 2-feet of snow to the mountains. The other scary part is that this low seems to like the aspect of living just off the coast of San Francisco where it will continue to pump moisture ashore along with some very breezy conditions. This system will be one to watch.
February 1 500MB 
February 1 Surface Analysis 
February 2 Surface Forecast 
February 3 500MB 
February 3 Surface Forecast 
February 4 Surface Forecast 
February 5 Surface Forecast
What does this mean for the Salish Sea? The coastal regions will have the usual somewhat breezy 15-25 knots of post-frontal south-westerlies that will continue to clock around to the north-northwest through about mid-day Saturday. This will result in a weak and very temporary onshore flow down the Strait of JdF which will end around mid-afternoon as another weak low-pressure system will move over the area by Saturday evening.
For the central and south Sound winds will be light tomorrow morning however as the high over central BC begins to build, a northerly flow will develop over the area getting up to maybe 15 knots over the central Sound.
It’s the north Sound, San Juan Islands, and the Strait of Georgia that will see the biggest change as that high will drive a blast of cold air down the Fraser River Valley, spilling into the Salish Sea. This will be significantly colder than what we’ve seen so far this year. There will also be significant wind associated with this blast especially in the northern San Juans and southern part of the Strait of Georgia. This will start to develop late Saturday night and continue into Sunday with the highest wind speeds out of the northeast occurring late Sunday night and into Monday morning when this area could see steady winds to 40 with gusts to near 50. With the very low temps and the possibility that as this blast runs into the moisture coming in off the Pacific we could get snow with some icing. This will bring down trees and power lines.
This snow event could then move south from Bellingham gradually weakening as it does so.
Have a great 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)