Bruce’s Brief for January 6-7 and Duwamish Head Race

And the word of the week is bombogenesis!, which is what happened to the East Coast this week resulting in hurricane force winds, lots of snow, all to be followed by record-setting cold temperatures. So what is bombogenesis? Very simply, this is a rapidly intensifying low-pressure system where the pressure drops at least 24mb over 24 hours. This system easily met the definition by dropping 59mb in 24 hours! I guess even though our weather is a little wet, we’ll take it compared to what they will have endured on the East Coast.

So how wet was it this last year? The record for rainfall in a year, as recorded at SeaTac since 1945, was 55.14 inches in 1950. In 1996 we had 50.67 inches and this year we had a measly 47.87 inches compared to a yearly average of 37.49 inches. What is interesting is that this last summer we also set a new record of 55 consecutive days without rain. This makes four consecutive years of over 44 inches of rain per year which I think we would prefer to the situation Cape Town finds itself in as it approaches “Day Zero” sometime this May. “Day Zero” is the day the taps go dry in Cape Town, the city simply runs out of water. Climate change? And Trump wants to cut funding to the National Weather Service? Kurt is kicking me to get back to my assignment for the day. (Ed. note, NO, he’s not. However, I see Trump’s reasoning: “If I fund the National Weather Service, all they’re going to do is come up with research and facts. I hate those things!”)

As we used to say at North U, one of the reasons why we enjoy sailboat racing is that no two races are ever the same. Except as I look back on last year, this is pretty damn close. Basically, there will be wind for the start and the run up to Duwamish, however, the wind will drop as you go north and then the Sound will glass off sometime around mid-afternoon. Last year Crossfire made it through the light air at Blakely Rock and Blake Island and got back into some wind and slammed the door on the fleet. The same thing could happen this year as there will be wind off the water and Crossfire has the rig to grab what there is up there.

As you can see from today’s surface analysis and from the GOES West Water Vapor picture, we have a dissipating low-pressure system moving through the area today. Pressure is already starting to rise and the wind is starting to clock around to the SW, a classic post-frontal pattern. Then you look at the Surface Forecast Chart for tomorrow and you see the problem, a huge gap in the gradient over the Pacific Northwest. Not all the models agree on this with some showing a nice south-southwesterly (8-10 knots) over the race course for the entire day. I’m not that optimistic. I think it is more likely that by the north end of Vashon things will start to get squirrely with big shifts and puffs from the SW. It will be important to sail the rhumb line from Three Tree to Alki and not sail too many extra miles chasing puffs. By Alki, have the drifter ready and don’t get too close to the beach. Remember also that with max ebb at 1300 hours and the fact that there will be lots of water coming out of the Duwamish, there could be a strong set to the west at the Duwamish mark. With the combination of very light air and anti-water at the mark, rounding could be challenging. The first boat around will have a huge advantage until they run out of wind again at Blakely Rock. From there to the finish will be a shifty bit of drag racing from hole to hole. The other bad news is that there will be no flood tide until early Sunday morning at 0512 hrs. Yes, the ebb will run from 0842 Saturday until 0512 Sunday.

Remember, the big Seattle Boat Show starts Friday, Jan 26th at CenturyLink Field. I’ll be working at the Information Booth both Friday and Saturday evening the first weekend, Sunday the 28th from 1000-1400, Monday the 29th from 1500-2000hrs, Tuesday the 30th from 1000-1500hrs, and Friday, Feb 2nd from 1600-2100hrs, so if you’re at the show please stop by and say hello.

 

mm

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)

Leave a Reply