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Time lapse of Golden Gate eddy

 
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windfind



Joined: 18 Mar 1997
Posts: 817

PostPosted: Wed Aug 01, 2012 9:24 am    Post subject: Time lapse of Golden Gate eddy Reply with quote

Hi Gang,

Golden Gate eddies, like the one in the time lapse below, are not found in the literature and are rarely noticed or mentioned by the NWS. Typically it is much harder to discern than in this video and on days with no fog we are often not even aware of it until it wrecks the forecast.

The time lapse shows the eddies counter-clockwise spinning winds west of the Golden Gate. First find the narrow opening of the Golden Gate. Then notice the circulation of the eddy and how it throws SW flow at the coast from Stinson to Crissy to Pacifica.

This eddy and it's SW flow often develops on days where there is strong NW flow west of the Golden Gate. For years this eddy caused me to blow many forecasts since all the models and data supported strong NW wind at the coast and inside much of the bay. So I would forecast solid winds at Waddell, Crissy, Coyote & 3rd even inside and suddenly SW flow would spoil the winds, especially inside, at each of those sites. While Larkspur. Treasure Island and Pt. Isabel would have winds much stronger than forecast.

Fast forward 15 years and most of the time I will uncover the eddy before the 7AM forecast. However sometimes it does not even spin up until 9AM so you will see a frustrating special update changing the forecast.

I think I am at the point on the learning curve eddy-wise that I may start issuing "Eddy Alerts" the night before so you know the forecast might change fast.

The hardest part is trying to guess the fate of the eddy. If it suddenly dies at noon then the NW wind will curve into the bay and Waddell at full strength making my dire eddy warnings look Chicken Littleish.

If the eddy does not die but enlarges or moves west like you see below then Waddell, Crissy, Coyote & 3rd hardly receive any wind and my warning of light winds inside seems dumb since it is actually near dead.

So on days when there I am still mentioning an eddy at 11:30AM keep an eye the windalert.com winds at Half Moon Bay, Ocean Beach and Half Moon Bay. If they are still SW at 2 PM and Stinson is SE then the eddy is probably going to weaken the Waddell, Crissy, Coyote & 3rd winds and jazz up the Pt. Isabel and Alameda winds.


Hope this helps some. If you find yourself lost in the satellite imagery let me know and I will make a version of the time lapse with annotations on the image.

Mike Godsey

weatherflow.com
windalert.com
iwindsurf.com
ikitesurf.com



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Hamilton_Burger



Joined: 09 Aug 2012
Posts: 1

PostPosted: Sat Aug 11, 2012 1:15 pm    Post subject: Reply with quote

Incompetent, irrelevant, and immaterial!
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2bluehawaiins



Joined: 07 Mar 2002
Posts: 171

PostPosted: Sat Aug 11, 2012 1:52 pm    Post subject: Eddy off GG Reply with quote

Thanks Mike,
I always like to see what causes the wind in the bay and forecasting has come a long way since the 80's when I used to call Lake Sonoma Marina and ask the girl at the counter if there were white caps near the dam. LOL



lake Sonoma May 1st 2011 005.JPG
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windfind



Joined: 18 Mar 1997
Posts: 817

PostPosted: Sat Aug 11, 2012 2:36 pm    Post subject: Reply with quote

Quote:
Thanks Mike,
I always like to see what causes the wind in the bay and forecasting has come a long way since the 80's when I used to call Lake Sonoma Marina and ask the girl at the counter if there were white caps near the dam. LOL


Hi 2bluehawaiins,

Thats funny about Lake Sonoma. I learned to waterstart at Lake Sonoma years ago. I remember wondering what made the lake windy when Bodega and the entire coast was fogged in some days.

Then there were the endless days sitting at home, or the college between my lectures, or on the beach trying to guess where the wind would be while listening to the NWS on the weather radio. Hour after hour, day after day they forecast 15-25 knots for the Bay Area all summer. There was one guy who had a slight speech impediment and always pronounced Dillon Beach as "Dillon Bitch" and Tomales Bay as "Tomallees Bay" in the wind reports.

Those experiences were the part of my motive as I moved from my North Coast Windline forecast hobby, to Windsight, to Call of the Wind, to iwindsurf.com to Weatherflow and now TransPac, America's Cup and Google forecasting.

It is easy to forget, especially if you are new to the sports, how incredibly easy we have it now compared to the past. Back then we just drove to a site following the fog pattern and hoped for the wind to build.

Imagine our life without any sensors, wind graphs, models, human forecasts! It would be like the 80's and we would have to drive and hope that our guess was right. And often we would actually have to spend the afternoon talking to real people about the wind and windsurfing rather than whining to anonymous strangers on the forums.

Mike Godsey
weatherflow.com
windalert.com
iwindsurf.com
ikitesurf.com
sailflow.com
fishweather.com
USAfishing.com
windnotes.phanfare.com/



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Last edited by windfind on Sat Aug 11, 2012 2:40 pm; edited 1 time in total
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windoggie



Joined: 22 Feb 2002
Posts: 2408

PostPosted: Sat Aug 11, 2012 2:40 pm    Post subject: Reply with quote

windfind wrote:
There was one guy who had a slight speech impediment and always pronounced Dillon Beach as "Dillon Bitch" and Tomales Bay as "Tomallees Bay" in the wind reports.

or San Lee-an-drow MA Rina

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2bluehawaiins



Joined: 07 Mar 2002
Posts: 171

PostPosted: Wed Aug 15, 2012 11:30 pm    Post subject: what causes the wind? Reply with quote

Yes MIke,
I still listen to the weather radio daily and try to figure what will happen with the weather around the bay area/coast. I have got some great winter days in February at Tomales bay because the weather radio said small craft adviser 20 to 35 knots.
Sounds about what I used to do as far as going to lake sonoma or mendocino and wait for the wind to build hopefully.

I think the fog at the coast and the hot weather in Healdsburg caused the wind to draw thru the mountains across the dam at lake sonoma. Kind of like what causes the wind in the gorge with the cool coast and the hot in the desert. I love sailing the Wall!
Take care Ted





windfind wrote:
Quote:
Thanks Mike,
I always like to see what causes the wind in the bay and forecasting has come a long way since the 80's when I used to call Lake Sonoma Marina and ask the girl at the counter if there were white caps near the dam. LOL


Hi 2bluehawaiins,

Thats funny about Lake Sonoma. I learned to waterstart at Lake Sonoma years ago. I remember wondering what made the lake windy when Bodega and the entire coast was fogged in some days.

Then there were the endless days sitting at home, or the college between my lectures, or on the beach trying to guess where the wind would be while listening to the NWS on the weather radio. Hour after hour, day after day they forecast 15-25 knots for the Bay Area all summer. There was one guy who had a slight speech impediment and always pronounced Dillon Beach as "Dillon Bitch" and Tomales Bay as "Tomallees Bay" in the wind reports.

Those experiences were the part of my motive as I moved from my North Coast Windline forecast hobby, to Windsight, to Call of the Wind, to iwindsurf.com to Weatherflow and now TransPac, America's Cup and Google forecasting.

It is easy to forget, especially if you are new to the sports, how incredibly easy we have it now compared to the past. Back then we just drove to a site following the fog pattern and hoped for the wind to build.

Imagine our life without any sensors, wind graphs, models, human forecasts! It would be like the 80's and we would have to drive and hope that our guess was right. And often we would actually have to spend the afternoon talking to real people about the wind and windsurfing rather than whining to anonymous strangers on the forums.

Mike Godsey
weatherflow.com
windalert.com
iwindsurf.com
ikitesurf.com
sailflow.com
fishweather.com
USAfishing.com
windnotes.phanfare.com/
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zpp66



Joined: 02 Apr 1994
Posts: 70

PostPosted: Thu Aug 16, 2012 1:47 am    Post subject: Reply with quote

Ha, I remember that guy on the weather radio too. Can't believe that's all we had back then. And then I actually carried a beeper (Call of the Wind)! All the while the forecasts have gotten better and better. Thanks and nice job Mike
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kirk



Joined: 10 Apr 2000
Posts: 158

PostPosted: Thu Aug 16, 2012 10:31 am    Post subject: Da Past Reply with quote

[quote="windfind"]
Quote:
It is easy to forget, especially if you are new to the sports, how incredibly easy we have it now compared to the past. Back then we just drove to a site following the fog pattern and hoped for the wind to build.

Imagine our life without any sensors, wind graphs, models, human forecasts! It would be like the 80's and we would have to drive and hope that our guess was right. And often we would actually have to spend the afternoon talking to real people about the wind and windsurfing rather than whining to anonymous strangers on the forums.


I remember getting a weather book buy some expert about Bay Area windsurfing and weather when I started... Windfinder: A windsurfing guide to the San Francisco Bay area & beyond 1989.... says Coyote was $3 to get in... now $6 making the pass a great deal.



I remember going to Coyote Pt park that would fill up on Saturdays by 1PM so we'd hang out and picnic, sometimes using boards as tables on ice chests... I had a weather radio that we'd get the 1PM report from Half Moon Bay buoy to see if NW wind was picking up that would later come in the gap.... A few years later I got a $400 hand held scanner so I could get the weather being reported to the pilots at SFO and Palo Alto airport to see which site had wind... often those pesky "Eddies" would make more wind at PA than CPt.... I could just barely get SFO with the scanner from my Los Altos home near Palo Alto after I moved there from Sunnyvale in 1994. I remember the joy of actually getting real time wind info from home that made it easier to decide PA or Coyote... We also had at HP in the early 1990s an Xwindows program that would display the hourly data (in Ken's report) on a big monitor and we could shift through past data to see it changing.... now we use iWindusurf's charts with many more sensors all over the world... often the final decision is driving where I check to see if the fog is in enough to favor PA over Coyote...
Now most don't show up until the sensors show wind.

Thanks for all the years of forecasting and teaching. It has sure helped me figure out where to sail in the South Bay...

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Kirk Out
http://bayareawindsurfing.blogspot.com/
http://kirklindstrom.blogspot.com/
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