sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery
Sail-World.com : America's Cup: Predictwind - Moderate breezes expected for Day 10
America's Cup: Predictwind - Moderate breezes expected for Day 10


'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

Predictwind shows a varied wind forecast for Day 10 Friday for Races 13 and 14 of the 2013 America's Cup. The first race starts at 1.15pm on Friday, local time with the second race scheduled for 1415hrs.

Today we again show a new feature of Predictwind - course routing optimised for wind and tide on the AC race course. 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

Officially the breeze is being forecast in the 10-15kts range - below the expected limit. A front is expected to arrive later in the day which will cause winds to increase, but this is not expected to affect racing. Predictwind's latest forecast shows winds higher than this, and with some variation between the two weather feeds meaning that the prognosis is not particularly certain.

With the racing at its regular start time of 1315hrs the wind feeds produced by Predictwind indicate that winds will be in the 15-20kts range. The key point is that one of the feeds is significantly stronger than the second.

Wind map for September 20, 2013 San Francisco at 1315hrs - Start of Race 13 -  PredictWind.com   Click Here to view large photo

The above image shows the wind speed and direction 1300hrs with breezes expected to be 15-20kts at the start of Race 13 - these are only average speeds and gusts will be higher, and may exceed the wind limit.

Wind graph for September 20, 2013 San Francisco at 1315hrs - Start of Race 13 - 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 significant feature is the variation between the two feeds - making for a less certain prognosis.

Upwind course projection September 20 2013 - faint purple line is for Race 13, Red dotted line is for Race 14 -  PredictWind.com  

The top image shows the wind speed and direction at 1400hrs with breezes expected to remain at 15-22kts at the start of Race 14 - these are only average speeds and gusts will be higher, maybe exceeding the wind limit of 23kts

Wind graph for September 20, 2013 San Francisco at 1415hrs - Start of Race 14 - 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 uncertain prognosis.

The third chart (below) shows the wind expectations for Friday and Saturday. Typically the forecast for Friday is revised upwards closer to the time of the race start. Note that sea conditions described in this chart are based on open water and are not descriptive of an enclosed harbour

Windpredictions for September 20, 2013 San Francisco for Friday and Saturday -  PredictWind.com  

The courses optimised by Predictwind for an AC72 show that the optimum course only has no real variation between races. The faint purple line shows the recommended course for Race 13 and the red dotted line shows the course recommended for Race 14. The mark positions used in this projection are only very approximate - and will vary on the course set for the day. At the bottom of the upwind leg the model shows that the boats can use the full width of the course due to the evenness of the tide.

The point here is that downwind is there is little variation in the options. And upwind in both models the fastest course is to the south, or cityside shore, aside from allowing a short leg to Alcatraz in the first race before heading for shore. 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 20, 2013 - faint purple line is for Race 13, Red dotted line is for Race 14 -  PredictWind.com  

Upwind course projection September 20 2013 - faint purple line is for Race 13, Red dotted line is for Race 14 -  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=114752

3:00 AM Fri 20 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:

22 Sep 2013  America's Cup Race 14 and maybe 15 Streaming Live Here !!
21 Sep 2013  34th America’s Cup - Oracle team USA claims another win
21 Sep 2013  America's Cup: Am-Cam video of Day 10
21 Sep 2013  America's Cup: Images from the RNZYS - Day 10
21 Sep 2013  America's Cup: Oracle Team USA adds to win total with Race 13 victory
21 Sep 2013  Gladwell's Line: Cup fever hits New Zealand heartland
21 Sep 2013  America's Cup: Kiwi Media Conference - Day 10 - Video
21 Sep 2013  America's Cup: Emirates Team New Zealand update - unlucky race 13
21 Sep 2013  America's Cup - Day 10 photos by Carlo Borlenghi
21 Sep 2013  America's Cup - Defender's race 13 win forces the Cup to day 11
MORE STORIES ...




News - USA and the World























2014 Pacific Cup - Scarlet Runner wins by Vanessa Yates, Hawaii












































Anna Tunnicliffe wins first event of Reebok Cross Fit Games + Video
2014 Pacific Cup - Skill and luck required for victory
Six Metre European Championship - Action resumes on day 4
BIC Techno 293 Worlds 2014 - Day 4
PWA Fuerteventura Grand Slam on the horizon
Rolex Big Boat Series - Golden Jubilee to take place this September
DH Pacific Cup - Running with the pack + Video
Women's Match Race Golfe du Morbihan - Testing day in Vannes
Brewin Dolphin Commodores' Cup - Ireland establishes solid lead
International Moth Worlds: Outteridge charges into the lead + Video
Marina Rubicón Round Canary Islands Race - First blood to Team Brunel
ISAF Youth Match Racing Worlds - Competition heats up on day 2
Laser Radial World Championships - Competition aplenty on day 3 +Video
Extreme Sailing Series - Penultimate Act to take place in Nice
Leukemia Cup - Images by Leighton O'Connor
Maxi Yacht Rolex Cup - Meeting of the grand designs
29er North American Championship - Final series kicks off
29er World Championship 2014 set to start in Kingston, Ontario
Barcelona and Parnu chosen for 2015 ORC championship events
2014 Race for Rady Yacht Race - Benefiting Rady Children’s hospital
CMRC Summer Invitational Series - Doubleheader events start tomorrow   
BIC Techno 293 Worlds 2014 - Day 3   
Sailing through STEM Night at California YC   
Six Metre European Championship - High temps and little wind on day 3   
Women’s Match Race Golfe du Morbihan - Light wind opener in Vannes   
International Moth Worlds: Rashley ahead as Aussies close in   
Brewin Dolphin Commodores' Cup - Unsatisfactory conditions on day 4   
ISAF Youth Match Racing Worlds - American unbeatable on day 1   
RS Feva World Championships - All set at Yacht Club de Carnac   
ISAF Rolex World Sailor of the Year Awards - Nominations now open   
BIC Techno 293 Worlds - Steady winds on day 2 + Video   
29er North American Open Championship - Qualifying series wraps up   
Opening ceremony O'pen Bic World Cup, Travemunde Week, Germany   
Six Metre Europeans - Wind fails to make an appearance on day 2   
Edgartown Race Weekend - Let the sailing (and good times) begin   
ISAF Youth Match Racing World Championship - Action commences July 23   
International Moth Worlds - Mothballed on day 4 + Video   
Brewin Dolphin Commodores' Cup - Ireland remains out front   
Spirits high as Team Alvimedica completes Transatlantic crossing   
Gladwell's Line: A change of direction needed in the America's Cup *Feature   


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 NEW US
LocalAds   DE  ES  FR  IT