Graham Easterling wrote:


snip



A big swell is dependent on fetch, wind strength & duration, and then travels
far beyond the area of generation.



.........and it travels on great circle tracks, which results in long-distance
swell sometimes arriving from directions that seem to be intuitively wrong.
Charts on a gnomonic projection reveal all in this respect. Gnomonic charts
give a very distorted appearance to oceans and land masses but on these charts
great circles are straight lines. For example, SW'ly winds associated with a
major hurricane off the mid-Atlantic coast of the USA will produce a swell that
reaches Cornwall from WNW.


--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org