Bruce’s Briefs: Wx for 24, 25, 26, and 27 Dec. It’s definitely going to get COLDER!

Lots of very interesting stuff in the weather charts, sat pic and Doppler radar. However, if you want some indication of just how cold it’s going to get just look at the 72 hour surface forecast chart from yesterday. The ice accretion line runs from near Yakutat, Alaska down the coast to halfway down the outside of Vancouver Island. This means the ocean (saltwater) spray will freeze when it hits your vessel. That is COLD!

The other interesting charts from today are the surface analysis, sat pic, and Doppler radar images. They all show the low centered just off our coast which will move onshore this afternoon bringing small craft advisories and gale warnings to our waters. This, in turn, will facilitate the arrival of an arctic front late Saturday and into Sunday brought in by a strong outflow from the Fraser River Valley. The 48 hour surface forecast chart shows a 42MB difference between the low over our area and the high in BC, note the tight spacing of the millibars over this area which will bring gale force northeasterlies to the Bellingham, the San Juan Islands, and the eastern Strait of JdF.  

This will also be reinforced by the jet stream being in a very strong meridional flow configuration. The main reason for this is an unusually strong mid-Pacific high-pressure system centered south of Kodiac and west of the mouth of the Columbia River. Combined with low pressure over our area, the jet stream is sandwiched between these two pressure systems which not only show up on the surface charts but also on the 500MB charts as well. This will keep a succession of frontal systems marching into California with the jet stream coming ashore near the California- Mexico Border.

So just how cold will it get? It’s possible that the high temperature from Sunday through Wednesday will never get above freezing and the low temperature could be down in the 15-16 degree F range. The coldest temps we’ve seen in a long time. Combined with the possibility of 4+” of snow in the lowlands starting Saturday night and continuing into Sunday we could be in for some very tough sledding. (Couldn’t help myself!)

I also got some questions about how this will affect boats moored in saltwater. The boats in freshwater definitely will need heat and make sure to leave the locker doors and floorboards over thru-hulls open so the heat can circulate. Interestingly enough the same will apply to boats moored in saltwater especially in areas like Shilshole and Elliott Bay. The reason is that with all the rain we’ve had, the freshwater will flow into these areas and being less dense than saltwater, will stay on top of the saltwater and potentially freeze especially if the wind is light. Regardless, it’s just a good excuse to go down and carefully check the boat over.

So have a very Merry Christmas and a Happy New Year!  

Bruce Hedrick

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)