Please select your home edition
Edition
Southern Spars - North Technology

America's Cup- Predictwind - Lighter winds and late build for Day 1

by Richard Gladwell on 6 Sep 2013
The America’s Cup Race Course, framed by the Golden Gate Bridge © Richard Gladwell www.photosport.co.nz

Predictwind indicates that light to moderate winds will prevail for Sunday, the first race day for the 2013 America's Cup. The first race starts at 1.15pm on Saturday, local time with the second race scheduled for 1415hrs. The 18fters racing in the International Series will have stronger breezes when they start racing around 1530hrs.

With the racing at its regular start time of 1315hrs the two feeds produced by Predictwind indicate that winds will be averaging around 10-15kts, however the key point in the forecast is that the breeze builds very sharply and if that increase in strength is delayed then races could be sailed in winds of 10kts.


The top image shows the wind speed and direction at 1300hrs with breezes expected to be only 10-12 kts at the start of Race 1 - these are only average speeds and gusts will be higher, but not enough to exceed the wind limit. There is a little variation in the forecast indicating a higher degree of certainty as to the outcome.

The key feature of the forecast is disagreement between the two feeds as to the rate of build of the breeze, but around race start they are consistent in their projection.


The second image (above) shows a graphic representation of the wind build - confirming the numbers for the prognosis. If the breeze builds later than predicted, then the light winds soon one the left of the graph will extend through to the race start time.


The top image shows the wind speed and direction at 1400hrs with breezes expected to rise to 15-18kts at the start of Race 2 - these are only average speeds and gusts will be higher, but not enough to exceed the wind limit.

The key feature of the forecast is disagreement between the two feeds as to the rate of build of the breeze, but around race start they are consistent in their projection.


The second image (above) shows a graphic representation of the wind build - confirming the numbers for the prognosis. If the breeze builds later than predicted, then the light winds soon one the left of the graph will extend through to the race start time.

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



The image below shows the wind speed and direction at 1500hrs for the 18fters with breezes expected to be peaking around 20kts at around 1600hrs - these are only average speeds and gusts will be higher, but not enough to exceed the wind limit. There is a little variation in the forecast indicating a higher degree of certainty as to the outcome.



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 image with the funneling of the breeze.

Developed by former Olympian, Jon Bilger (470, 1992), www.predictwind.com!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 www.predictwind.com!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 www.predictwind.com!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.

Schaefer 2016 Ratchet Block 660x82Wildwind 2016 660x82Newport Boat Show 2016 660x82

Related Articles

Dateline Rio - Sailing Olympics review - as good as it gets?
The Rio Sailing Olympics was widely judged to have been the best of recent times. The Rio Sailing Olympics was widely judged to have been the best of recent times. The weather was better than Weymouth and Qingdao, the courses more varied, but from a working media perspective, it was the people running the Rio regatta who really made the difference.
Posted on 26 Aug
Rio 2016 - Plain speaking by triple-medalist on Olympic sailing moves
Triple Olympic medalist, Santiago Lange has been on the sharp end of changes made to Olympic classes and formats Santiago Lange, a six-time Olympian and Bronze medallist in the 2004 and 2008 Olympics, won his third medal – Gold sailing in the Nacra 17 class. With that length of experience at an Olympic level, having sailed the Laser, Tornado and now Nacra 17 classes his comments on the future shape of the Olympic regatta was one of the highlights of the Medallists Media Conferences.
Posted on 25 Aug
An Q&A with Steve and Heidi Benjamin about the NYYC’s 2016 Queen’s Cup
Sail-World caught up with Steve and Heidi Benjamin to learn more about Heidi’s historic win in the NYYC’s Queen’s Cup. When it comes to U.S. Grand Prix sailing, it’s hard not to encounter the names of Steve and Heidi Benjamin. The two highly polished sailors have been successfully campaigning their series of yachts, named SPOOKIE, for years, starting first with a Carkeek 40 and progressing to their TP52. I caught up with Steve and Heidi to learn more about Heidi’s historic win in the NYYC’s Queen’s Cup
Posted on 19 Aug
Rio 2016 - Images of the penultimate race in the Finns - Scott wins
Sail-World's Richard Gladwell was on the water for the final race of the Qualifying Series of the Mens Finn Sail-World's Richard Gladwell was on the water for the final race of the Qualifying Series of the Mens Finn, in what potentially could have been Giles Scott's (GBR) Gold medal winning race. In the end, the current world champion won in style.
Posted on 15 Aug
Rio 2016 - Images from the Mens RS:X Medal Race
Sail-World's NZ Editor, Richard Gladwell, was on the water at the Medal Race for the RS:X class Sail-World's NZ Editor, Richard Gladwell, was on the water at the Medal Race for the RS:X class won before the race by Dorian van Rijsselberghe (NED) without needing points from the Medal Race. Nick Dempsey (GBR) was second on a similar basis.
Posted on 15 Aug
Rio 2016 - Sailors talk of Life at the Extreme on the Atlantic Ocean
Certainly the Volvo Ocean Race catchcry of Life at the Extreme is not a phrase associated with the Sailing Olympics. The 470 crews were suffering the mixed emotions of survival of an extreme test by nature, the cold, and for some elation at their placings, after Thursday's battle for survival. In conditions that looked more out of the Volvo Ocean Race, than an Olympic sailing regatta, crews battled 20kt plus winds and Atlantic Ocean rollers that towered up to four metres.
Posted on 13 Aug
Rio Olympics - Fourth gallery of images the fearsome Niteroi course
Fourth image gallery from racing on Day 4 in the Mens and Womens 470 class on the Niteroi course in the Atlantic Ocean Fourth image gallery from racing on Day 4 in the Mens and Womens 470 class on the Niteroi course in the Atlantic Ocean - sailing in 3-4 metre swells and 20kt plus winds. believe it or not the sea conditions were worse inshore as the fleet encountered the backwashed Atlantic rollers
Posted on 12 Aug
Rio 2016 - Third image gallery of 470's braving the Atlantic Ocean
Third image gallery from racing on Day 4 in the Mens and Womens 470 class on the Niteroi course in the Atlantic Ocean Third image gallery from racing on Day 4 in the Mens and Womens 470 class on the Niteroi course in the Atlantic Ocean - sailing in 3-4 metre swells and 20kt plus winds
Posted on 12 Aug
Gladwell's Line - The challenges of Guanbara Bay
The decision to run Medal Racing on the Pao de Acucer course, probably won't be remembered as one of the brightest The decision to run Medal Racing on the Pao de Acucer, probably won't be remembered as one of the brightest of the 2016 Sailing Olympics. Over shadowed by a 1300ft tall granite and quartz mountain in the shape of a sugarloaf, the bay suffers from dramatic windshifts, and huge variance in wind pressure.
Posted on 11 Aug
Rio 2016 - Fresher breezes expected inside and outside on Day 3
Stronger winds are expected for the third day of racing in the 2016 Olympic Sailing Regatta in Rio de Janeiro. Stronger winds are expected for the third day of racing in the 2016 Olympic Sailing Regatta in Rio de Janeiro. Two of the fleet scheduled to race outside on the Atlantic Ocean course off Copacabana Beach, while the 470 Men and Women will race inside on Guananara Bay.
Posted on 10 Aug