Where the Wind Is
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In his book, A Sand County Almanac, Aldo Leopold wrote:

The wind that makes music in November corn is in a hurry. The stalks hum, the loose husks whisk skyward in half-playful swirls a tree tries to argue, bare limbs waving, but there is no detaining the wind.

Hi, I'm Bryan Yeaton for the Weather Notebook.

Wind happens when air flows from an area of higher pressure to an area of lower pressure, kind of like rolling a marble down a ramp. The greater the pressure difference between the high and low, the steeper the pressure gradient-or the steeper the ramp-and the faster the wind. Look at the isobars on a weather map-the circles and lines that separate pressure systems. The closer they are together, the stronger the wind.

But wind doesn't flow straight from the high to the low. In the Northern Hemisphere, wind flows clockwise and outward from the high, and counterclockwise and inward, toward the low. So when a storm is barreling up the east coast, that counter rotation-which meteorologists call "cyclonic"-picks water out of the Atlantic, and dumps it on the shore with northeast winds, thus the name: Nor'easter.

Air in the upper atmosphere can move quite differently from surface winds, which is why the Mount Washington Observatory is beaming a green laser-called Lidar-into the New Hampshire sky. The Lidar bounces off air molecules and tells what the wind is doing way up there.

For links to sites where you can check out the isobars on weather maps, as well as the Lidar facility, check out today's program at www.weathernotebook.org. The Weather Notebook is produced by the Mount Washington Observatory, with support from Subaru. Thanks today to Assistant Producer, Doug Sanborn.