Overview
Today the low pressure to the northeast starts to strengthen and intensify, bringing building gradient breeze. Some wind shear might be present with puffs associated with right shift in the wind. With offshore flow, expect a puffy, shifty race course with more wind away from land. Pressure will start lighter - probably around 8 knots, and gradually build with some puffs to 15 possible late in the day. Models differ slightly, so pay attention to the wind angles around 1000 to see which model is winning.
Weather Analysis
The low pressure system that kept wind light yesterday is beginning to strengthen and move north, bringing a stronger offshore gradient flow.
The European model shows wind right of 270 at 1000AM.
In contrast, the North American Model shows wind farther left, around 250-260 at 1000.
Yesterday the North American Model (NAM) did a better job predicting the light offshore conditions. Today the North American Model shows moderate wind shear (pictured below) with wind aloft 10-15 degrees farther right than at the surface. Look for a correlation between puffs and right shifts today, especially if the breeze starts out to the left of 270 at 1000AM.
Surface wind around 250-260.
600m wind (puffs) farther right.
Throughout the day, both models show a right trend to the breeze with the European model ending up as far right as 315 by 1800. This right trend will probably be visible on the water, as it will bring more breeze down the course.
Geography Versus Gradient
Geography will play a big role today with a weather shoreline. Generally weather shorelines are associated with less pressure, and more left shift, but this might be a small effect relative to the righty puffs if you see the right shift-puff correlation discussed above, playing out. In either case, the straight set around the top mark should benefit from both right puffs, and an average right geographic trend as you get away from land.
Where you guys will be sailing, a wind direction of around 300 degrees is perpendicular to the shoreline, so if you are on the water when the wind gets to the right of 300, don’t be totally married to a strategy that worked prior.
Summary
Overall, expect a puffy, shifty day with light conditions to start, building and trending right throughout the day.
Expect the breeze to trend to the right, with pressure bringing right shift.
Clouds forming to the north in the late afternoon may help to indicate the pressure build and right shift.
Look for a correlation between puffs and right shift - especially if wind is left of 270 at 1000.
Edges of the fleet will be high percentage in the gradient breeze.
Evaluate wind direction during the starting sequence, as late shifts will change the favor of the line a lot.
Outlook
Tonight a cold front comes through, causing a strengthening breeze Saturday that will remain from the N-NW. Saturday, expect a fade to the N-NE for the final day of racing.
