Are You Weather Wise?
By Jeff Rennicke
Sure, those TV weathermen have their Doppler radar and their fancy satellites. But my grandmother had her onions. And to her they were worth a slew of Willard Scotts. "Onionskins very thin, mild winter coming in," she'd say as I watched her slice vegetables on a late autumn evening.
In an age when the touch of a button will get you the Weather Channel, such snippets of folk wisdom may seem more than a bit quaint. But some pretty impressive weather watchers say there's truth behind a lot of that homespun lore. Here's some of the smartest.
That Rainy Day Feeling
Ever hear the rhyme Mackerel sky, rain is nigh? "That's one of the best," says Jym Ganahl, a meteorologist with WCMH-TV in Columbus, Ohio. "Cirrocumulus clouds, clouds that look like fish scales, often show up in advance of a slow-moving front -- the kind that's likely to bring rain within twenty-four hours."
Here's another portent of dreary skies: A ring around the moon or sun, and rain approaches on the run. "The halolike ring is actually light reflected through ice crystals of high, thin clouds that are often 500 to 600 miles in advance of a storm front," Ganahl says. "So if the system is moving at thirty miles an hour, you can expect rain in about twenty hours." According to the National Weather Service, there's a 65-percent chance that precipitation will follow a ring around the sun or moon.
Notice sea gulls hugging the beach? Not good. Sea gull, sea gull, sitting on the sand, it's a sure sign of rain when you're on the land. "I suspect there's some truth in that saying," says ornithologist Laura Erickson, author of For the Birds: An Uncommon Guide. "With their hollow bones and air sacs, birds may detect changes in barometric pressure and react to them." When a storm approaches, the air pressure drops -- a possible sign to those gulls of an impending downpour. By staying on the ground, Erickson says, they avoid the struggle of flying through high winds and rain. (来源：英语论坛 http://bbs.englishcn.com)
Your sense of smell, too, can predict rain. When ditches and ponds offend the nose, watch for rain and stormy blows. "The science of that one is right," says Charles Wax, climatologist for the state of Mississippi. "Just before rain, humidity rises. And humid air carries tiny particles of the foul-smelling decaying matter from swamps and ditches."
You might even be able to predict a downpour without ever leaving your house. When windows won't open and salt clogs the shaker, the weather will favor the umbrella maker. The high humidity that can produce thunderstorms also has an irritating habit of making wood swell and salt stick together.
Not every old saying is a warning of tempest. Heavy dew in the morning light, shows no rain before the night. This adage pans out because the heaviest dew develops when the ground cools quickly overnight -- which happens with clear skies and calm winds. "Conditions like that often mean you're at the center of a stable high-pressure system," says Richard Keen, a meteorologist at the University of Colorado. "It's usually twelve hours or more before a storm system takes over."
Even a few clouds overhead can be a good thing. If woolly fleece decks the heavenly way, be sure no rain will mar the day. Fleecy white clouds are probably fair-weather cumulus clouds, says Charles Wax. "Those puffy clouds are only a few hundred feet thick, which means they're not very developed at all. And that's a sign the atmosphere is relatively stable."
When the goose honks high, fair weather is nigh: No huge mystery with this one. High pressure, which dominates in fair weather, creates tail winds that give high-flying geese a free ride. These birds are only one barometer. Cranes aloft, the day is soft; swallows soar, good weather more. You get the picture.
Come Rain or Shine
Some weather sayings cover all the bases. Red sky at night, sailors delight; red sky at morning, sailors take warning: This may be the most famous of all weather sayings, one that's even referenced in the Bible (Matthew 16:2-3). It has withstood the test of time because it's so often right. The red of a sunset is caused by light bouncing off dust particles in dry, stable air. Since most weather in the country moves from west to east, that means good weather is approaching. Red in the eastern sky at sunrise could mean that dry air is on its way out.
If you miss the sunrise, search out some cows. Tails to the west, the weather's the best; tails to the east, the weather's the least. Cows seem to dislike taking a strong wind face-on, preferring to have it hit their rump. So they act as a kind of bovine weather vane. Tail into the prevailing fair-weather winds from the west, all is clear. Tail to the east, signaling winds swirling counterclockwise around low-pressure centers, and wet times could be ahead.
That same wisdom lies behind another old saying, one to keep in mind at your next barbecue: When the smoke floats west, good weather is gone; when the smoke floats east, good weather is come.
It's true that not every bit of lore holds up. Punxsutawney Phil, the world's most famous groundhog? Cute, but his shadow tells you zilch about spring. The woolly bear caterpillar, whose colored stripes are supposed to foretell the severity of winter? "The color of that caterpillar has as much to do with winter as it has to do with the price of lawn furniture," says Dave Thurlow, radio host of The Weather Notebook.
As for those onionskins, do they actually tell you anything about the coming cold? I've decided I don't really want to know. After all, weather lore is one thing -- but a grandmother's wisdom is sacred.