Please select your home edition
Edition
SailX 728x90

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

by Richard Gladwell on 8 Sep 2013
The America’s Cup Race Course, framed by the Golden Gate Bridge © Richard Gladwell www.richardgladwell.com

Predictwind indicates that light to moderate winds will prevail for Saturday, 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.

Barz Optics - FloatersNorth Technology - Southern SparsT Clewring - Generic

Related Articles

Gladwell's Line - Emirates Team NZ launches shadow AC50
Emirates Team NZ took a late but significant step along the road to the 35th America's Cup, with the launch of their AC4 Emirates Team NZ took a late but significant step along the road to the 35th America's Cup, with the launch of their AC45S - as the test boats are called in the Protocol which governs the 2017 event. The bloated Protocol, which now runs to 83 pages of legalese, is restrictive on the size of boat that can be built as a test platform but doesn't restrict the number that can be built.
Posted on 22 Jun
Platino recovery - Family confirms that tug has made rendezvous
Reports in social media say a salvage tug has made a rendezvous with the Platino earlier than expected. Reports in social media by family and friends of Nick Saull, the crew member killed during a catastrophic incident abroad the 66ft yacht Platino say the salvage tug which left on Tuesday night has made the rendezvous earlier than expected. The Facebook report says the tug, Sea Pelican, arrived on Friday morning, the weather in the area has eased and with a more favorable outlook.
Posted on 16 Jun
Rio 2016 - Double Olympic medallist on the delights of Guanabara Bay
Olympic Gold and Bronze medallist Bruce Kendall updates on the 2016 Olympic venue at Guanabara Bay. Olympic Gold and Bronze medallist, and now a windsurfer coach, Bruce Kendall has made several trips to the 2016 Olympic venue at Guanabara Bay. He updates on the pollution issue which is clearly not going to be resolved in a couple of months, and also shares his views on the venue from a sailing competition perspective.
Posted on 14 Jun
America's Cup - Artemis win Chicago as Team Japan wins two races
Louis Vuitton America's Cup World Series got three races away on Super Sunday. After losing the first official day of racing due to light winds and the non-arrival of the onshore breeze, Louis Vuitton America's Cup World Series got three races away on Super Sunday. From a racing perspective this was probably the best day of racing yet in the series which counts for points in the Qualifying Series of the America's Cup in 11 months time.
Posted on 12 Jun
America's Cup - Emirates TNZ NZ and Oracle capsize in Chicago Practice
Emirates Team New Zealand and Oracle Team USA capsized in Practice Racing at the Louis Vuitton ACWS Chicago There was action aplenty on Practice Day at Louis Vuitton America's Cup World Series Chicago, after Emirates Team New Zealand capsized in their match with Oracle Team USA, and then Oracle Team USA capsized later in the day. Team NZ's skipper skipper Glenn Ashby performed some impressive acrobatics ejecting from the AC45 capsize, without injury.
Posted on 11 Jun
America's Cup - Changes proposed to control future Cup options
Changes are being mooted to put the America's Cup on a longer-term footing according to the Daily Telegraph (UK) News that changes are being mooted to put the America's Cup on a longer-term footing is being floated in the Daily Telegraph (UK) by the British Challenger, Land Rover BAR. According to the Telegraph, some of the teams in the 2017 America's Cup are keen to lock-in parameters which would bind successive holders of the a style and frequency for the next America's Cup Match.
Posted on 8 Jun
America's Cup - AC50 construction uncovered - Part 2 - Wings and Costs
Second part of a two-part series looking at the AC50 construction progress at Core Builders Composites Second part of a two-part series looking at the construction progress at Core Builders Composites, and features of the AC50 class which will be used in the 35th America's Cup in Bermuda. Tim Smyth takes us on a tour of the CBC facility in Warkworth, and hour's drive north of Auckland. Where several AC50's, components and wingsails are under construction or have already been shipped to the teams.
Posted on 5 Jun
America's Cup - AC50 building program well underway at Core Builders
For the first time in America’s Cup history, Sail-World can publish photos of America’s Cup yachts during construction. With the forthcoming America's Cup in Bermuda just under 12 months away, production of the wingsails and AC50 one design hulls and components are well underway at Core Builders Composites in Warkworth, about an hour north of Auckland. For the first time in America’s Cup history, Sail-World can publish photos of America’s Cup yachts during construction.
Posted on 3 Jun
America's Cup - Arbitration Panel Hearing over Kiwi Qualifier for July
ACEA CEO, Russell Coutts has confirmed that the Arbitration Panel will hold its first Hearing in July. In a yet to be published interview in Sail-World, America’s Cup Events Authority CEO, Russell Coutts has confirmed that the Arbitration Panel will hold its first Hearing in July. This is the first official indication that the three person Arbitration Panel had even been formed, however Sail-World’s sources indicated that it had been empanelled since last January, possibly earlier.
Posted on 27 May
Rio 2016 - The Qualification Games - Part 2
Yachting NZ's refusal to nominate in three classes won in the first round of 2016 Olympic Qualification is unprecedented Yachting New Zealand's refusal to nominate in three classes won in the first round of 2016 Olympic Qualification is without precedent. Subject to Appeal, the Kiwis have signaled that they will reject 30% of the positions gained in the ISAF World Sailing Championships in Santander in 2014.
Posted on 22 May