PredictWind: Major wind change expected to hit Port Phillip, Melbourne

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1:35 PM Tue 13 Jan 2009 GMT

'PredictWind: Winds at 0500hrs on 14th January 2009. Showing winds of 5-10 knots from a northerly direction blowing out of Port Philip, Melbourne' PredictWind.com

The wind prognosis from PredictWind.comis for a significant shift in wind direction today, Wednesday, accompanied by a major increase in strength for several hours before returning to a standard Port Philip seabreeze on Thursday.

The charts below show the sudden change in strength and direction before midday on Wednesday, accompanied by a steady drop in air temperature.

The readings are all based at Williamstown, venue for the 2009 Flying Fifteen World Championships.

The two feeds used to as input data to the prognosis show as follows

0800hrs 5kts from 220 degrees
1100hrs 22kts from 160 degrees
1400hrs 23kts from 160 degrees

0800hrs 11kts from 200degrees
1100hrs 19kts from 160 degrees
1400hrs 21kts from 170 degrees

Note all readings above are average windstrength only, and will be exceeded in gusts.

Although the two feeds don't agree, this is normal. The fact that they are almost exactly the same in terms of a change in direction in time and angle indicate that the change will almost certainly take place. There is a small variance in strength of a couple of knots or more.

The sea condition is relatively low on Wednesday increasing on Thursday and Friday the direction of the swell is from 220 to 235 degrees.

PredictWind: Winds of between 21 and 31kts are projected by the weather feeds used by PredictWind, on 14th January 2009 around Williamstown, Port Philip, Melbourne. The sudden increase in strength must be compared with the other chart showing change in wind direction. - PredictWind.com

Williamstown - showing a shift in wind direction to around 160 degrees at around 1030hrs on 14 January - PredictWind.com

PredictWind: Showing the drop in temperature expected at the time of the windchange and shift to southerly winds in Port Philip, Melbourne - PredictWind.com

PredictWind: Wave prognosis showing a rising swell from a southerly direction in Port Philip - PredictWind.com

The animations below show the change in wind strength and direction as the change occurs in the Williamstown, Port Phillip area. They show the wind changing direction and then staying reasonably steady in strength before easing. On Thursday the seabreeze will remain however it will be of less strength and in the same direction (seabreeze).

PredictWind: Winds at 0800hrs on 14th January 2009. Showing winds of 10-15 knots from a southerly direction blowing into Port Philip, Melbourne. Note the change is still taking effect inland - PredictWind.com

PredictWind: Winds at 1100hrs on 14th January 2009. Showing winds of 15-20 knots from a southerly direction blowing into Port Philip, Melbourne - PredictWind.com

PredictWind: Winds at 1400hrs on 14th January 2009. Showing winds of 20-25 knots from a southerly direction blowing into Port Philip, Melbourne - PredictWind.com

PredictWind: Winds at 1700hrs on 14th January 2009. Showing winds of 20-25 knots from a southerly direction blowing into Port Philip, Melbourne - PredictWind.com

PredictWind: Winds at 1400hrs on 15th January 2009. Showing a seabreeze blowing into Port Philip of about 1-0-15kts - PredictWind.com

PredictWind.comsoftwareand forecasting service was developed by Alinghi weatherman and top youth and Olympic sailor, Jon Bilger. It is a subscription only service, with 30day free trial. PredictWind does give significant benefits whether you are a racing sailors who wants to plan a regatta or race, or a cruising sailor looking for the peace of mind that a five day forecast can bring. Get your subscription now at PredictWind.comand take advantage of their 30% discount for life offer - and read what top sailors have to say about PredictWind

by Richard Gladwell, Sail-World