I think that only is possible adjust the probability of change of the wind intensity, and direction.
Perhaps the speed of the wind is harcoded.
There are some discussions about this and the possibility of change the weather patterns in a campaign.
http://subsim.com/phpBB/viewtopic.ph...ghlight=random
http://subsim.com/phpBB/viewtopic.php?t=46991
with low randomization you can have a weeks of storms or calm waters
with a high randomization you will never boored , it can change in hours and its a more challenge.