Originally Posted by GeorgeB
Not sure what model you are looking at but those of us who race on the Bay know that the City side is where you go for wind relief. The shear line runs from Blackaller to Alcatraz and on to just outside Blossom Rock. If you think it’s windy by the City, you ought to try a mark rounding at Harding Rock on the same day!
SF Ports website that is now at SJSU. It WAS a great resource for wind data both current and archived but now it only has the most current wind data; the archive page has not been working correctly since they moved it from the government website.
While I agree that the Blossom Rock area is lighter, the wind does funnel through at Alcatraz. I'd say the shear runs from Fort Point down to Aquatic Park/Pier 39, but out near Alcatraz is right in the middle of The Slot so I don't understand why you'd say it's much lighter to the south of Alcatraz.
I'm not saying I disagree with you about there being even more wind out near Harding Rock; but to say the east side of Alcatraz is inside of the wind shear line, to me is incorrect (to my experience). The last two times we watched Oracle go by us at 35+kts (within 200 yards) flying both hulls was right between Alcatraz and the Cityfront. Wind was in the low 20s.
I'd show you where I'm referring to if there was access to archives but as of right now there is not; and on the many days I've sailed in heavy wind and later checked the archived data I'd say it was accurate. Often times the heaviest wind vectors are shown just to the SE of Alcatraz with a huge easterly shift compared to the predominant wind direction. Latitude 38 has a saying "counterclockwise for comfort" for times when sailors take guests because tacking through the heavy wind on the south side of the bay is more challenging than tacking up through Raccoon Strait. I don't disagree with that statement.