Here are wind and waves for this Friday night:
So far so good: the wind is from the west and the waves are predictably building with increasing fetch from Illinois to Michigan side of the lake.
Now here are the predictions for Saturday noon or 15 hours later:
The winds have shifted to the north somewhat but are still predominantly west. The wind shift to the north was gradual. The waves are still gaining height from west to east.
But what happened to the wave direction?! Is it just me or does it seem odd that on the west side of the lake the waves have turned nearly perpendicular to the wind direction! I've heard of refraction and diffraction (waves changing direction due to bottom topography or obstacles in their way) but I can't see how these laws would change the wave direction so much! There is also Coriolis Effect that turns the winds around the HI/LO pressure areas but I don't even understand that one well enough to see how it could possibly apply here.
What forces are at play here? I am stumped! Is it just a mistake? Anybody have ideas?
PS This may be a clue but to me it just adds to the mystery: associated with the wind starting to shift north NOAA predicts 1.5 knot north to south surface currents in the middle of Lake Michigan
I am sure they have something to do with the predicted wave direction ... just no idea what!