In article , Bob Gardner wrote:
According to "The Weather Book," by USA Today weather editor Jack Williams,
a one-half-pound pressure difference between places 500 miles apart will
accelerate still air to 80 mph in three hours. Increase the distance to 1000
miles and the windspeed will be 40 mph after three hours. Don't know about
you, but 80 mph surface winds are beyond my meager skills. I think your .5
inch figure is overstated.

I had a 0.05 difference about 30 miles apart last weekend and thought that
was unusually high.

Morris (what's an order of magnitude among friends?)