PredictWind has more breeze for Friday

by Richard Gladwell, Sail-World on 14 Aug 2008
www.predictwind.com!PredictWind is showing more wind for tomorrow, Friday at the Qingdao Olympics.

Racing today has been cancelled. Tomorrow all five courses will be in operation.

However www.predictwind.com!Predictwind is showing winds blowing at 12 knots tomorrow maybe more.

The actual graphs show substantially more wind however these are predictions for 40metres and to get to a five metre level which is of more interest to sailors in Qingdao and fans at home, the reading should be divided by a factor of 1.7.

Developer of the PredictWind application, and member of the Alinghi weater team in 2003 and 2007, Jon Bilger comments: 'Regarding the forecasted wind strength, as the model predicts at 40m, and the height that sailors are interested in is around 5m, and often there is a high wind gradient, you will find dividing the wind strength by 1.7 is often a good factor.'

In the graph above it can be seen that there is a high degree of variation between the Canadian feed (CMC) and the US feed (GFS) represented by the solid line.

This variation indicated the degree of uncertainty in the forecast, and if the Canadian feed is more correct then substantially stronger winds could be expected.

Regional 5 Day Text Forecast for Qingdao: CMC
Date	Hour	Speed (Knots)	Direction (Magnetic)
Wed 13	2100	6	140
Thu 14	0000	7	150
Thu 14	0300	7	150
Thu 14	0600	6	140
Thu 14	0900	7	140
Thu 14	1200	9	150
Thu 14	1500	8	160
Thu 14	1800	10	10
Thu 14	2100	12	70
Fri 15	0000	14	110
Fri 15	0300	7	320
Fri 15	0600	29	-10
Fri 15	0900	25	30
Fri 15	1200	18	10
Fri 15	1500	15	10
Fri 15	1800	13	10
Fri 15	2100	13	0
Sat 16	0000	10	10
Sat 16	0300	11	-10
Sat 16	0600	9	0
Sat 16	0900	9	10
Sat 16	1200	14	30
Sat 16	1500	10	20
Sat 16	1800	10	30
Sat 16	2100	10	20