Home WeatherBruce's Briefs Bruce’s Weather Brief: October 17, 2014, With Tips for STYC Races

Bruce’s Weather Brief: October 17, 2014, With Tips for STYC Races

by Bruce Hedrick

Another very interesting week for weather as we slowly make our transition to fall in the Pacific Northwest. The temperatures are still above “normal” and we are definitely in line for more rain. It’s also interesting to note two late season hurricanes as Gonzalo takes aim at Bermuda, and Ana goes by to the west of the Hawaiian Islands, and we still have 5.5 more weeks of hurricane season.

Saturday's surface forecast from NOAA.

Saturday’s surface forecast from NOAA.

This weekend we have the Sloop Tavern Yacht Club Fall Regatta (29 boats) combined with the Race Your House event (31boats) for liveaboards only. Very cool. Anything that gets more folks out on the water and enjoying the Sound is a good thing.

As you can see from the Surface Charts by 0500 PDT on Saturday morning we’ll still have the remnants of today’s cold front lingering over us with that huge 975 MB low moving towards us. The good news is that we’ll have wind in the morning from the south at around 10 knots ± . Then you look at the surface chart for 1700 hrs on Saturday and you’ll see that the gradient has eased over the Northwest while the next front is marching towards us. Generally speaking there will be more wind to the north of Puget Sound and less wind in south Sound. Over the course of the day racers can expect the wind to drop in velocity and shift from the south to the south-southwest. By late in the afternoon the wind velocity could be less than five knots.

Late Saturday's surface forecast from NOAA.

Late Saturday’s surface forecast from NOAA.

Tides will be relatively moderate as the flood will run from about 0800 until 1400 and will be at max at around 1100 with a velocity of .6 knots at West Point.  You should also remember that with a southerly that has been blowing for about 24 hours combined with significant rainfall (around 1”) the freshwater boundary layer from the Duwamish River will run along the south face of West Point and can neutralize the flood. It will be easy to tell if this is in play if you see a muddy streak in the water going north from West Point.

The courses will start off Shilshole with the pancake buoy marking the outboard end of the line.  The weather mark will probably be West Point and after that who knows. The important thing will be to get a clear air start and then sort out the tides around Shilshole. As with West Point there will probably be significant outflow from the locks flowing to the north-northwest which you will also be able to see on the water. This counter current will go out to just beyond the pancake buoy and run as far north as Meadow Point. You’ll have to balance fighting that current with wanting to be in on the breakwater to take advantage of the localized south-southeasterly breeze coming out of the Ship Canal. If you don’t get that perfect start don’t hesitate to tack out to port to get to the flood tide.  If you’re in the flood don’t tack back to starboard until you can come in to the south of the Ship Canal.

(Click to enlarge)

PredictWind's outlook for 1100 Saturday.
PredictWind's outlook for 1400 Saturday.
PredictWind's outlook for 1700 Saturday.

The downwind leg will depend upon what the leeward mark is however if you are going to Meadow Point it may pay to work back into the flow out of the ship Canal to avoid the flood tide.

As usual, before you leave the house check Washington State Ferry Weather, check the readings at the West Point particularly the barometric pressure tendency to see if pressure is rising which would indicate that the front has passed and the wind will start to shift from the south to the southeast. Then check the Western Washington Surface conditions to see what the pressure gradient looks like from Olympia to Bellingham.

Have fun out there and enjoy what will still be a warmer and dryer than “normal” weekend.  Next week does look a little damp.


Saturday's tides at West Point.

Saturday’s tides at West Point.


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