ryan78 wrote:Coriolis Force. Prevailing winds in the Northern Hemisphere tend to deflect West to East and in the Southern Hemisphere deflect East to West. The closer to the equator you go the less affect of the winds. Now obviously there are things like Jetstreams that come and go, and are especially strong in the winter time when the troposphere is a lot lower, but generally that is the direction of the winds aloft. That's why TATL is always quicker going Eastbound then Westbound. I would assume same goes for Hawaii-Mainland.
I flew YYZ-HEL-YYZ last year on Finnair, the Eastbound leg was 7H10M flying time, Westbound was 9H05m, strong East-flowing jetstreams really slowed us down. It's also the same reason you see the Northeast US and Canadian Maritimes get hammered with huge winter storms. Weather builds over the Rockies and Coriolis Force pushes it East where it builds over the plains and then dumps 3 feet of snow on the Northeast.
I'm sorry but your explanation doesn't fit with reality - I live in the Southern Hemisphere, and we definitely have prevailing westerlies at altitude in this neck of the woods. Check out:
https://earth.nullschool.net/#current/w ... ectangularCoriolis force affects the direction high and low pressure systems rotate (in the Southern Hemisphere high pressure systems or anticyclones rotate anticlockwise, in the Northern Hemisphere they rotate clockwise, and the opposite for low pressure systems or cyclones), but to say it tends to deflect winds "east to west" is a bit of an oversimplification. My understanding is that prevailing winds at altitude are primaily a function of the overall distribution of high and low pressure systems, which are actually predictable, and that in the equatorial region they tend to be easterly, while as you move towards mid lattitudes (which is where most of the flight path from Hawaii to North America would be) they tend to be westerly.
Actually that site I've linked may be useful for helping you friend visualise wind Mcluvin.
V/F