myiW Current Conditions and Forecasts Community Forums Windsurfing Videos Buy and Sell Services
 
Hi guest · myAccount · Log in
 SearchSearch   ProfileProfile   Log in to check your private messagesLog in to check your private messages   RegisterRegister 
If Eddy goes...the wind won't: Blog update

 
Post new topic   Reply to topic    iWindsurf Community Forum Index -> Southwest USA, Hawaii, Mexico
View previous topic :: View next topic  
Author Message
windfind



Joined: 18 Mar 1997
Posts: 817

PostPosted: Wed May 15, 2013 11:21 am    Post subject: If Eddy goes...the wind won't: Blog update Reply with quote

Gang,

I just added a satellite animation update at the bottom of the blog.

http://blog.weatherflow.com/eddy/

There is a huge Catalina Eddy spinning today off Southern California. This blog has imagery and animations that show the nature of the eddy and why it is bad news for Southern California beach winds.

Mike Godsey
iwindsurf.com/ikitesurf.com



Eddy.jpg
 Description:
 Filesize:  38.16 KB
 Viewed:  2207 Time(s)

Eddy.jpg




Last edited by windfind on Wed May 15, 2013 3:09 pm; edited 1 time in total
Back to top
View user's profile Send private message
sorenson



Joined: 04 Jul 1999
Posts: 35

PostPosted: Wed May 15, 2013 2:18 pm    Post subject: Reply with quote

How about this for an alternative caption:

"If dat Eddy don't go, da wind's not gonna blow"

Wink
Back to top
View user's profile Send private message
kevinkan



Joined: 07 Jun 2001
Posts: 1168
Location: San Francisco

PostPosted: Wed May 15, 2013 2:54 pm    Post subject: Reply with quote

Hey Mike,

You may have answered this question in the past, but I was wondering why strong NW winds will make it to Alameda in the spring, but not the rest of the year. April 15 was one of those days this year.

Thanks

_________________
Kevin Kan
Sunset Sailboards, San Francisco CA
http://www.sunsetsailboards.com
http://www.sunsetsailboards.com/blog
http://www.facebook.com/sunsetsailboards
Live Onsite Reports via Twitter
Back to top
View user's profile Send private message Visit poster's website
windfind



Joined: 18 Mar 1997
Posts: 817

PostPosted: Wed May 15, 2013 3:38 pm    Post subject: Reply with quote

Hi Kevin,

It is funny that you asked since I am currently working for a major internet company that needs information about that same wind issue in the same area.

The images below answer your question visually. But for details:

Basically, in the spring after the passage of a upper trough the North Pacific High's surface NW winds move to the coast and we get NW "clearing winds" at the surface. But since the back side of the upper trough is over us we sometimes have very strong W to NW winds just aloft. As you can see in the TOP image this mean we have 2 winds targeting the Bay. NW surface winds that funneled into the Golden Gate by the coast range following a weak pressure gradient to the Central Valley (weak because it is mostly full of cool low pressure air) But the NW winds aloft crash into the coast range and the turbulent air passes over the Bay Area and may steer the NW wind towards Alameda.

In the summer the storms are gone and upper trough mostly pass to our north. And the Central Valley is hot making a thermal low pressure area and a strong pressure gradient to the coast. So the NW wind curving into the Golden Gate makes a sharper turn towards the only sea level gap in the East Bay hills at Sherman Island. This means Alameda is often bypassed by the main wind flow. In fact if it was not for some of the NW wind coming through Alemany Gap near Candlestick and crossing the bay and turning towards the Altamont pass there would be almost no summer wind at Alameda.

Mike Godsey



AlmedaNW.jpg
 Description:
 Filesize:  212.23 KB
 Viewed:  2102 Time(s)

AlmedaNW.jpg


Back to top
View user's profile Send private message
cbknap



Joined: 03 Jun 1997
Posts: 301

PostPosted: Wed May 15, 2013 3:40 pm    Post subject: Reply with quote

SoCal sailors should watch the Point Vicente sensor, just north of Cabrillo, for real-time data on the eddy. LAX and Cabrillo can both be showing SW or WSW but until Point Vicente stops showing SE, Cabrillo and points south will not have enough wind to go sailing.
Back to top
View user's profile Send private message
windfind



Joined: 18 Mar 1997
Posts: 817

PostPosted: Wed May 15, 2013 3:53 pm    Post subject: Reply with quote

Point Vicente, as you can see in the imagery below stick further out into the eddy. So if it looks like the eddy has died on the Cabrillo to Sunset corridor sensor be sure to check out Point Vicente for a reality check. If the eddy is still spinning there will be southerly winds there and the winds is unlikely to get very strong at the beaches.

The best way to use the Point Vicente is to go to our web site Windalert.com and zoom the wind graph like you see below. Watch to see if the wind goes more westerly. If it does that early enough and there is clearing then the Cabrillo to Sunset corridor might get some usable wind.

Mike Godsey



SanVicente.jpg
 Description:
 Filesize:  162.81 KB
 Viewed:  2083 Time(s)

SanVicente.jpg


Back to top
View user's profile Send private message
kevinkan



Joined: 07 Jun 2001
Posts: 1168
Location: San Francisco

PostPosted: Wed May 15, 2013 4:28 pm    Post subject: Reply with quote

thanks Mike!
_________________
Kevin Kan
Sunset Sailboards, San Francisco CA
http://www.sunsetsailboards.com
http://www.sunsetsailboards.com/blog
http://www.facebook.com/sunsetsailboards
Live Onsite Reports via Twitter
Back to top
View user's profile Send private message Visit poster's website
NickB



Joined: 30 Jun 2009
Posts: 498
Location: Alameda, CA

PostPosted: Wed May 15, 2013 4:35 pm    Post subject: Reply with quote

windfind wrote:
In fact if it was not for some of the NW wind coming through Alemany Gap near Candlestick and crossing the bay and turning towards the Altamont pass there would be almost no summer wind at Alameda.
Mike Godsey


Hi Mike, that is very interesting. I windsurf exclusively Alameda. Is there a pattern one can check on the peninsula (and/or east bay) sensors that would indicate higher chances of sea-level planing winds in Alameda?

Another thing I noticed in the summer months is that you have to get further and further towards the harbour bay ferry channel to catch sea-level winds. Closer to the beach the wind is too high for windsurfing (while good at kite height)...

Thanks for all the info!
Back to top
View user's profile Send private message
windfind



Joined: 18 Mar 1997
Posts: 817

PostPosted: Wed May 15, 2013 5:46 pm    Post subject: Reply with quote

Hi Nick,

Pretty busy today so just a few quick hints about Alameda

1. Stronger NW to W wind on the ridges or at the new Golden Gate sensor on top of the S. tower.

2. Strong pressure gradient to Bakersfield rather that just Sacramento since that will tend to make the wind exit through the Altamont Pass rather than mostly through the Delta.

3. Watch the Sierra Point sensor near Candlestick since it picks up wind coming through Alameny Gap towards Alameda.

4. Watch Mark's forecast since he lives and kites at Alameda and has the best handle on the local winds there.

Mike
Back to top
View user's profile Send private message
NickB



Joined: 30 Jun 2009
Posts: 498
Location: Alameda, CA

PostPosted: Wed May 15, 2013 6:43 pm    Post subject: Reply with quote

perfect, thank you so much, it's all clearer now.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    iWindsurf Community Forum Index -> Southwest USA, Hawaii, Mexico All times are GMT - 5 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum

myiW | Weather | Community | Membership | Support | Log in
like us on facebook
© Copyright 1999-2007 WeatherFlow, Inc Contact Us Ad Marketplace

Powered by phpBB © 2001, 2005 phpBB Group