sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery
Sail-World.com : America's Cup: Predictwind - Fresh breeze for Final Day 15
America's Cup: Predictwind - Fresh breeze for Final Day 15


'The America’s Cup Race Course, framed by the Golden Gate Bridge - today the wind blows from right to left, and the ebbing tide flows from left to right against the windflow. The blue sea that can be seen behind the City to the right, is not ocean but the greater expanse of the San Francisco Bay - which exits through the relatively narrow channel under the Bridge.'    Richard Gladwell ©    Click Here to view large photo

A fresh San Fransisco breeze is expected on Day 15, the Final Day, of the 34th America's Cup, for Wednesday, Race 19 of the 2013 America's Cup. The final race is due to start at 1.15pm on Wednesday, local time.

Towards the bottom of this story we feature Predictwind's course routing optimised for wind and tide on the AC race course, and using an AC72 performance profile. It is included to show that the effect of the tide on the race course and race strategies. See bottom of story for the course variations.

For the official line on how the current factor is determined click here Today the tide is flooding (coming in through the Golden Gate) and will negate the previous advantage that exists with an ebbing tide.

With the final race of the regatta set for its regular start time of 1315hrs the wind feeds produced by Predictwind indicate that winds will be around 15-17kts. The feeds produced by Predictwind are close to agreement on the strength at the race start time, and there is only small build in the breeze over the morning.

Officials will add the strength of the tide to set the new wind limit, which will take it just over 24kts. On the basis of this forecast, the winds will be well under that level.

The forecast does not take account of the influence of fog, which can have several effects on the race course winds.

Wind map for September 25, 2013 San Francisco at 1300hrs - Start of Race 19 -  PredictWind.com   Click Here to view large photo

The above image shows the wind speed and direction 1300hrs with breezes expected to be 15-17kts at the start of Race 19 - these are only average speeds and gusts will be higher. The only issue of concern is the more northerly wind direction in some areas of San Francisco Bay, which could affect the set of the course.

Wind graph for September 25, 2013 San Francisco at 1315hrs - Start of Race 19 - indicated by the vertical yellow line. Read the actual data above the graph section -  PredictWind.com   Click Here to view large photo

The second image (above) shows a graphic representation of the wind build - confirming the numbers for the prognosis.

The third chart (below) shows the wind expectations for Wednesday. Note that sea conditions described in this chart are based on open water and are not descriptive of an enclosed harbour

Wind-predictions for September 25, 2013 San Francisco for Wednesday -  PredictWind.com  

The courses optimised by Predictwind for an AC72 show that the optimum course only. The red dotted line shows the Leg 2 course recommended for Race 19. The mark positions used in this projection are only very approximate - and will vary on the course set for the day.

In the second course projection, for Leg 3 the tide is expected to be in flood (incoming) for this race, and boats will need to avoid its effects upwind by taking the city shore.

Downwind course projection September 25, 2013 - Red dotted line is for Race 19 -  PredictWind.com  

Upwind course projection September 25, 2013 - Red dotted line is for Race 19 -  PredictWind.com  


Two weather feeds are used by Predictwind, the key to the accuracy of the forecast lies with the graphs, as when the two lines for the two feeds are quite close together and following each other in the trend, then the likelihood of the forecast is high. If there is separation to any marked degree, then there still some issues to be resolved but usually 24 hours from the race they are well aligned.

The Predictwind model takes various weather feeds and then polishes these, part of this process is factoring in the effect of local topography on the breeze - well demonstrated by the images with the funneling of the breeze.

Developed by former Olympian, Jon Bilger (470, 1992), PredictWind application was used by the Swiss team Alinghi to win the 2003 and 2007 America's Cups, and has become the leading wind system used by racing and recreational sailors around the world. It is available on a subscription basis and also with a free forecast option.

A mobile app for Android and iPhone is available and PredictWind is probably the most used app on the Sail-World iPhone.

Real time local wind observations have been added as further functionality.

You can check the weather anywhere in the world, and get a five day forecast, plus a variety of other features and functions of PredictWind. The app is synchronised with your PC, so that your latest set of locations are always available without resetting each time you change a device.


by Richard Gladwell

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=115012

1:27 PM Wed 25 Sep 2013GMT


Click here for printer friendly version
Click here to send us feedback or comments about this story.

Click for further information on
2013 America's Cup

Related News Stories:

26 Sep 2013  America's Cup: Monsta's view of the key moments of the 34th Match
25 Sep 2013  America's Cup 2013 Day 14 Press Conference - the pressure mounts
25 Sep 2013  Amerrica's Cup: Images from Bay and Ashore - Day 14
25 Sep 2013  America's Cup: More Images from the Bay - Day 14
25 Sep 2013  America's : More images from Day 14
25 Sep 2013  America's Cup: Images from on the Bay - Day 14
25 Sep 2013  America’s Cup: SHOWDOWN!
25 Sep 2013  America's Cup Final photos by Carlo Borlenghi
25 Sep 2013  America's Cup 2013 Race 19 - NOT Just another race
25 Sep 2013  America's Cup: Oracle Team USA update: Winner takes all
MORE STORIES ...




News - USA and the World

The first annual WetaFresh is a big success by Tim Wieringa, Muskegon, MI














Techno 293 Worlds - France and Italy claim titles by International Windsurfing Association,














420 World Championship - Singapore and Spain out front by 420 International Class Association,






























Lightning strikes cut short CFJ Nationals by Andy Kopetzky, Santa Monica Bay








Sevenstar Round Britain and Ireland Race sets off August 10th
PWA Fuerteventura Grand Slam - Antoine Albeau victorious on day 5
Snipe Western Hemisphere and Orient Championship headed for San Diego
WPA Championships - Kids race divisions offered
New Clever Pig launched by US Sailing
America's Cup: Group agrees to co-operate in London Meeting
Copa del Rey Mapfre - Build-up reveals some remarkable enthusiasm
Marblehead NOOD Regatta - Images by Leighton O'Connor
America's Cup: Two AC72 skippers discuss Foiling Moths and the Cup
RS Feva World Championship - Brilliant sailing on day 2
America's Cup: Alameda makes overtures on Venue hosting for San Fran *Feature
Cape Panwa Hotel Phuket Race Week 2014 - Relishing a challenge
Edgartown Race Weekend - BBBR and Round-the-Island Race winners named
Etchells Invitational Cup - Aussies take early lead in Cowes
PWA Fuerteventura Grand Slam - Antoine Albeau strikes back on day 4
Aquece Rio – International Sailing Regatta - All set for test event
ISAF World Sailing Rankings for 28 July 2014
29er World Championship - All set in Kingston
ORC World Championship - Third Course area opens for huge fleet
Day one of the Allen RS Feva World Championships
Anna Tunnicliffe: Final two days of the 2014 Reebok CrossFit Games   
Joachim Aschenbrenner takes gold at ISAF Youth Match Race Worlds 2014   
Maxi Soh scores double wins in CMRC Summer Doubleheader   
29er World Championship opening ceremonies in Confederation Park   
PWA Fuerteventura Grand Slam - Action resumes on day 3   
Land Rover Sydney Gold Coast Yacht Race Start 2014 VIDEO   
Laser Radial Men’s World Championship 2014- Final day   
2014 Pacific Cup - Scarlet Runner wins   
Gladwell's Line: America's Cup - Joint Statement is a curious note *Feature   
ISAF Youth Match Racing World Champ - Top four battle it out for final   
BIC Techno 293 Worlds 2014 - Day 6   
PWA Fuerteventura Grand Slam - Wind teases competitors on day 2   
Women’s Match Race Golfe du Morbihan - Action-packed day of racing   
Herreshoff Marine Museum announces successful fundraising campaign   
Brewin Dolphin Commodores' Cup - The most comprehensive victory yet   
Anna Tunnicliffe fourth at mid-point of 2014 Reebok CrossFit Games   
2014 29er North American Open Championship - Australians win   
INSA Sabot II Invitational Regatta - Erik Hou claims victory   
CMRC Summer Invitational Series - Maxi Soh wins Doubleheader A event   
International Moth World Championships - Nathan Outteridge wins   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News





Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL WAS US
LocalAds   DE  ES  FR  IT