Bruce’s Weather Brief for Sloop Tavern Blakely Rock Benefit Race – Sunblock Every 2-3 Hours!

If you liked last weekend, you’ll love tomorrow. Once again, the models are diverging as we get closer to race time. Not unusual this time of the year as the weather in the Pacific is trying to transition from winter to summer.

Wind speed vs air pressure at West Point
Wind speed vs air pressure at West Point

The Pacific High is still well south of its summertime residence and storm systems are pushing it around and keeping it from becoming more round, stronger and more stable. See the 1700 Surface Forecast Chart.

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The only real known forecasts with a high degree of accuracy are the tides and currents.

Tides for tomorrow are:

0803      Low        6.35 feet

1258      High       8.7 feet

1939      Low         1.02 feet

Currents at West Point:

0846      Slack

1017      Flood     .16 knots

1220      Slack

1613      Ebb          .71 knots

2004      Slack


As you can see from the Surface Forecast Charts there is very little gradient over the Pacific Northwest. When you log the pressure readings at 1200 hours on Friday you find the following:

Forks                        1023.4

Bellingham          1023.1

SEA                            1023.4

PDX                           1022.6

In other words not much. What’s interesting is that there has been a northerly all night and this morning over most of the race area even though the National Weather Service has been forecasting a southerly for the morning then changing over to a northerly in the afternoon with the same for tomorrow, sort of. The culprit here is the Swihart effect which says that in the absence of a pressure gradient over the Pacific NW and the presence of abundant sunshine causing heating of the concrete and blacktop jungle known as the City and surrounding environs of Seattle, combined with a flood tide, will initiate a northerly  in the Sound. So with two days of beautiful, clear skies and temps near 70⁰ you’re getting plenty of heating. This will probably carry over to tomorrow, at least that’s what we’re hoping for. Regardless, you’ll still need to track the pressure gradients and the wind over the area, especially the ferry weather at Edmonds and Elliott Bay.

So if there is a northerly, how do we sail this race? The first item to check when you leave Shilshole and get out to the starting area is what is the flag doing at West Point. If it’s like this morning, you’ll notice a very slight shift to the NNE. When you start with a northerly, the first mark is Meadow Point so having to leave the mark to port always creates some interesting rounding problems especially for the deep draft vessels that would rather come in on port since the starboard tack approach can get you into some skinny water. Since there is a flood you’ll want to set with the pole to starboard and aim towards the mark at Blakely Rock. If you get slightly lifted as you get close to West Point, you might want to gybe to port. If there is a northeasterly at West Point there will be more wind under the bluff and you can hold that until you get lifted above Alki and your heading has you between Alki and Duwamish, then gybe back to starboard and aim at the Rock. Just don’t hit it….

On the way back from Blakely Rock put it on the wind on port tack and you’ll be heading towards the vicinity of Four Mile Rock. Tide may be slack or just starting to ebb so remember just how far out the shallow area goes from Four Mile to West Point. It almost always claims someone and with the ebb you’re going to be there for a while unless you get some help from the photoboat. Go in as close as you dare before tacking on to starboard. The puffs will be lifts and the person on the main and traveler will be working really hard to take advantage of each and every puff.

Once at West Point you’ll want to hold onto starboard tack to take you off the Point and stay in the ebb tide. Tacking too close to West Point will run you into the back eddy that sweeps along the north side of West Point. Tack to port when you stay outside of the restricted zone at the entrance to the Ship Canal. Then plan on one tack at the breakwater to make the finish.

This was the optimistic race forecast. On the other hand if it goes according to the forecast models and we start with a southerly that then clocks to a southwesterly and dies as we transition into a northerly in the later afternoon, it will be a matter of drag racing from puff to puff and sailing the shortest possible course. The big boats with tall rigs and code 0’s could have a real advantage on the reach/run back to Meadow Point. The next problem will be negotiating the rounding because the deep draft boats are going to have to tack immediately at Meadow Point because over the winter the sand bar has moved off the beach and there is now a bump to the north of the usual location of the bar.

Have a great race and don’t get sunburned!




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)

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