MHeadWindRose
A typical sea breeze will initialize with an east to ESE direction then will gradually veer through the day as it strengthens. Peak winds will typically be between 3-5pm this time of year then winds slowly fade into evening with a very slight backing. Marblehead itself is quite challenging as the sea breeze “zone” can exist right near or on the race course and if the breeze hasn’t matured or is only weak, you can see considerable difference in winds and directions from one side of the course to the other with inshore winds stronger and more veered. Peak winds will typically occur a few hours after maximum heating of the day.The strongest sea breeze situation tends to be when we see a cool front pulling off of New England that gradually fades. The westerly flow behind the front tends to see a slight downsloping to the coast which heats the winds thus an early westerly will tend to heat the inland temperatures rapidly. The dry airmass allows the solar heating to go mostly into heating the surface. After a weak offshore morning, the sea breezes come on suddenly and strong. Occasionally this setup can push 18-20 knots into late afternoon. This July we have seen an uncharacteristically active synoptic situation where frontal boundaries have been stalling on or near the MA coast. These fronts tend to spawn areas of low pressure off of the Carolinas that ride up the front and can sometimes add on easterly or NE flow into Marblehead. In fact just last week we saw Tropical Storm Beryl that raced up just off of Nantucket. Thus, a good idea is to keep track of this front and watch the updated forecast charts for signs of offshore Low development. Last year’s races we watched a similar setup with a stalled offshore front but it didn’t amount to much except it’s presence kept a NE breeze in place albeit light for the first 2 days. By day 3, the ridge was able to dominate the region and thus a sea breeze was able to come on and winds veered to the SE and picked up (see graphs).Check out the new Sailflow weather station installed on Children’s Island! Knowing what forces are driving the winds is of great importance to gaining the edge on your competition. Sailflow.com provides real-time sensors as well as forecast products complimentary through the race period at www.sailflow.com/marblehead In cooperation with North Sails, Sailing Weather Service is offering free precision race forecasts for this event. Sign up at http://na.northsails.com/ew/ew_main.taf
