question about s.f. bay weather reports

sailingdog · May 17, 2009

You might want to try Sailflow.com instead. BTW, the wind readings are typically taken at 35 AGL, and may not reflect what you see on the surface, especially in a smaller boat with a shorter mast.

rardiH36 · May 17, 2009

For Angel Island -- Seems to Be Pt Blunt

This url connects to the SF Bay wind observation/windflow modeling website for the USGS/NOAA. At the bottom of the chart Pt Blunt on Angel Island is listed as the location.

http://sfports.wr.usgs.gov/wind/Stations.shtml

I'm not sure where the GG Bridge met site listed on the chart is located, but there is an anemometer located right in the middle of the bridge just above the pedestrian walkway.

Also this URL from NOAA shows the same wind information as the windandtides website. So this seems to be the source: http://www.wrh.noaa.gov/mtr/versprod.php?pil=OMR&sid=DAR

I certainly agree with you that after an afternoon's sail out of Sausalito, then later checking the Angel Island and GG Bridge data, what me and my boat experienced most often has little correlation.

But there is little doubt that the wind velocity and direction is most often all over the map depending on where we are on the bay; particulary this year it seems to me. Sailing out of Sauslalito, often the wind is virtually zero until well past the Spinnaker restaurant towards San Francisco. Then a few hundred yards further on, wind can be blowing at 15 knots or more. (Better be ready for a suddenly strong wind to hit a non-moving boat.) When I was out this past Friday about noon, the wind was blowing very strongly in the slot just east of the GG Bridge. We were healing strongly close-hauled even with the first reef taken in on the mainsail. Then heading out under the bridge, the wind suddenly diminished to moderately light in the area between the bridge and Point Bonita. On many days this past winter and into this spring, the only wind might be right in the slot just to the east of the GG Bridge. Everywhere else maybe not even enough wind to make headway against the current. I haven't been through Racoon Straight very much this season so far for this reason.

rardi
(@ Marina Plaza - Sausalito)

rardiH36 · May 17, 2009

Angel Island Wind Gauge - A Nice Blow this Afternoon

Just got home from a late afternoon sail. Checked the Angel Island met info. A nice blow. Good and strong. I don't have a wind force device on my boat. But considering we were on the first reef and we had five or so wraps of the headsail still on the furler, that we were heeled almost to the rail, the Angel Island info supports the exhilarating conditions on the bay today:

18:09 Sun 31 kts SW 34
17:09 Sun 28 kts SW 33
16:09 Sun 26 kts SW 29
15:09 Sun 24 kts SW 28
14:09 Sun 16 kts SW

cat38skip · May 17, 2009

The SF Bay is the poster child for micro-climates. You can be basking in nearly calm air behind Angel Island and 100 yds later roaring through The Slot with 20+ kt winds and dashing around trying to find your foulies. Then into the shadow of The City and a nice cruise again. The weather observations and postings for any location are for that exact location only and you can't generalize more than a few 100 yds in any direction. That is what makes sailing The Bay so much fun!

Stu Jackson · May 17, 2009

I recommend that you read

"Sailing The Bay" by Kimball Livingston. The micro weather climates are explained very well. Hurricane Gulch south of Sausalito is a basic example, and it's not only this year, it's all the time.

sailingdog · May 18, 2009

Glad to help...and yes AGL is above ground level.

patsheridan said:
hey sailing dog. thanks for the link. tons of great info here; much more thorough than windandtides. btw, AGL meaning above gound level, possibly?

alex · May 18, 2009

Point Blunt

The wind report for Angel Island is at Point Blunt. SE corner of the island closest to Alcatraz. That is usually the windiest spot as it is in "The Slot" between GG Bridge and Berkeley.

rardiH36 · May 18, 2009

Re: Point Blunt

For PatSheridan:

Since it might not be readily noticed when you log on (since just a small reference in the "Welcome UserName" spot near the top of the forum page), I've sent you a "private message". So please check.

rardi

Napa Ed · May 19, 2009

patsheridan said:
head out under the golden gate at the tail end of an ebb, mess around a bit just outside the gate, then head back in on a flood. know the gate can be difficult and am wondering if this makes sense to you.pat

Not too difficult if you're coming from Sausalito:

Regardless of current direction, staying to the north side of the channel avoids the strongest current with one exception. Watch commercial fishermen coming back in against the flow. on-line view at: http://www.oceangrafix.com/o.g/Char...cific&viewChart=Entrance-to-San-Francisco-Bay

They come in north of Potatopatch Shoal, follow the Bonita Channel, around Pt Bonita and stay close to the north coastline. In a sailboat with limited hull speed and aux power, it's even more important to follow the contours of the waterline closely (Bonita Cove). When you get just east of the North Tower, you get strong currents (old station at Lime Point). Even large sailboats with inboards get stuck in the current and mark time.

Pick a day/time when the flood tide is stronger than the ebb. Better to not get out than not get back in. http://windandtides.com/ and http://sfports.wr.usgs.gov/cgi-bin/SFPORTS/zoom_cb.cgi?x=185&y=285

Stu Jackson · May 19, 2009

under the Golden Gate

patsheridan said:
i'll take a look to see if i can find this book locally before i look online.

i've got a sail plan i've been condsidering in my 24' islander, wondering your thoughts: find a day with dependable 10-15 knot winds (good luck there), head out under the golden gate at the tail end of an ebb, mess around a bit just outside the gate, then head back in on a flood. know the gate can be difficult and am wondering if this makes sense to you.

The book is at West Marine. I don't even know if it's available online, altho I guess Amazon has everything.

I hesitate to say "Don't fear the Golden Gate Bridge" and Napa Ed has good ideas, but I've been goin' out there successfully for years, both overnights to the south, Drake's Bay to the north and long daysails to the Lightship or ship channel. As "Sailing The Bay" says, forget about winter time (except for exceptionally good weather) but summertime you will find that once you get out to Pt. Diablo, which is halfway out to Pt. Bonita, the winds lighten up. Why? Because the Gate itself is a BIG funnel and the winds in the Bay could be honkin' 20-25 or higher and it's only 10-15 "outside."

Avoid both the North Tower because of the tide rips (Ed's right) and the south Tower and never, ever go south of the south tower. The S tower throws some vicious side winds so stay clear until you get to know what happens under the bridge.

If you go during spring tides you'll find, time-wise, that going near the end of the ebb will set you up for a good ride back on the flood. Neap tides, find your own timing and go for it and by using either the north shore or the BIG Baker Beach curve, you can stay out of the main current if you have to "fight" it.

Get the book, so I won't have to retype what Kimball's already written. besides, the book is a FUN read. For anyone who is ever considering coming here to sail, or who just wants to understand why we LOVE it so much, buy the book.

It's lovely out there, and you have a great boat to do that with. Bon voyage!

question about s.f. bay weather reports

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