Shifty Wind Currents
Watch wind currents and their shifts.
Click link to view: Wind Patterns in the Atlantic; then click and drag on the globe to view wind currents in other regions of the world.
If the moon were positioned closer to the earth, scientists surmise the winds on earth might be affected dramatically. While the increase in the moon's gravitational force on the earth would not only dramatically affect the globe's tidal currents, it would however significantly increase the winds' velocity to such an extent that trees might be uprooted, buildings destroyed and people starting to burrow underground. That kind of wind shift would challenge not only the way people live, but also the human races' very existence. Let's thank our lucky stars the moon is where it is and that forecasters surmise it won't inch much closer to the earth for at least a few thousand years.
Unlike the tides which have a table of predictability, winds are much more fickle. While the moon has some impact, the sun has greater influence. Temperature causes winds to form on and over land and sea. So do land formations, types of cloud cover, high and low pressure areas are other major factors in wind's creation, direction, velocity and shiftiness.
The above circular graphs show how frequently, how fast and from what direction the wind blows from for Providenciales, the northern part of the Caicos in southern Bahamas, in February.
When wind shifts arrive, they not only change direction, they often alter the intensity of the breeze. Referred to as gusts or fresh breezes, they sometimes change calm to chaotic. These shifts can take a steady and constant wind and make it veer, back and/or oscillate. When the wind shifts to the left, it is called "backing"; when shifting to the right, it is called "veering"; when shifting back and forth, it is called "oscillating".
A "header" is a wind shift that causes your boat to head away from the wind's direction in order to keep your sails full.
All you have to do to notice how shifty the wind is is watch a wind generator for a few moments. It turns, pivots and hums with each gust. While a flapping flag can reveal these various shifts, watching a wind generator's volt monitor display the amp fluctuation of each change in velocity provides some reference point to the power and frequency of these shifts.