With two days to go until the start of Race 1 of the best of nine series constituting the America's Cup Match, Alinghi and Team New Zealand will be keeping a close eye on the weather. So what's forecast?
Light winds associated with a lingering high-pressure system have dominated weather Auckland's for the past week. However on Saturday the situation looks like it will change, as a cold front sweeps north east across New Zealand and pushes the high-pressure out to the east.
A cold front in New Zealand's summer is not as active as some of the fronts we saw earlier for the Louis Vuitton Cup. It will however bring a change of 'air mass', with the threat of rain and much cooler air (from the Southern Ocean). Winds ahead of a cold front in New Zealand are usually from the NW and veer to the SW on the passage of the front. The 'warm' NW winds are moderated by the high ground to the west and north-west of the Hauraki Gulf and on Saturday the winds ahead of the front look pretty light on the race course.
The exact timing of the front is difficult to predict at this early stage, but it looks like it should pass through around 1000-1200 on Saturday and we are likely to see SW winds behind the front. The south westerly winds look like they will be stronger possibly between 15 - 23 knots and are likely to be backed a little by the time they reach the race course area to SSW. Historically, winds from SW are the 'over achievers' as they tend to be accelerated by the high ground on each side of the track into to the Hauraki Gulf.
Land normally has the effect of slowing surface wind due to friction, wind that flows across Manukau Harbour (south west of Auckland), prior to swinging north around Rangitoto, escapes a long land track and can generate stronger wind lanes in a south westerly wind. These winds are further accelerated due to the 'channelling effect' of the WaitakereRanges and the Humna range south of the Gulf that generates a 'river' of wind that encroaches on the south western quadrant of the Hauraki Gulf.
Should the front 'stall' over the mountains of the central part of North Island, then the lighter winds ahead of the front look more likely come the starting gun on Saturday afternoon. It should be emphasised that predicting Saturdays wind four days ahead is a very inexact science, the Hauraki Gulf winds are notoriously fickle.
The outlook beyond Sunday is for lighter winds as another high-pressure system pushes east from Australia bringing fine and sunny conditions, like we have seen in Auckland for most of the month so far.
Want to watch the America's Cup Match
Whilst for most of us, if not already there, it is too late,some countries will be broadcasting the races. The America's Cup website has details of broadcasters' schedules click here