A layman's guide to the weather: Reading the clouds

Posted: Thursday, July 19, 2001

Predicting the weather in Southeast is easy: prepare for rain, and eventually it will pay off. But anglers, kayakers and other outdoorsmen wanting to gauge the weather during a trip need to understand a few basic concepts.

"The key to it all in Juneau is to watch the wind," said Jerry Painter, the Meteorological Technician who prepares the Nowcast, also known as the short-term forecast. "The winds tell the tale."

The wind interacts with Juneau's geography - the ocean, the mountains and Canada, he said. The ocean puts moisture into the air, while Canada usually sends drier air. Mountains keep things interesting by physically changing the direction and elevation of wind, and hence of clouds.

According to Painter, the general pattern in Juneau indicates that winds coming from the northwest to the south bring rain, while winds from the east generally will not.

"If the wind's coming off the continent, it'll be relatively dry. If it's coming off the ocean, it'll be relatively wet," Painter said.

Wet wind delivers rain. However, mountains create odd patches of protected and exposed areas, each of which will have its own peculiar idiosyncrasies.

"There's so many little microclimates," said Painter, referring to those odd patches. "It's not easy (to predict the weather)."

This explains why Juneau in general averages about 100 inches of rain per year, but Juneau International Airport receives only about half that amount.

And, as any boater knows, ocean weather can be flighty.

"You can go from calm seas to whitecaps in 15 minutes," said Sue Hargis.

As both a kayaker and the Boating Safety Coordinator for the United States Coast Guard, Hargis has come up with a pre-launch routine that emphasizes evaluation of weather conditions.

"Before I leave, I call the Weather Service and get the latest weather forecast," she said. She also notes the prevailing winds at her launch site.

"The other really major thing is to check the tides," Hargis said, noting that tidal action affects the behavior of waves.

Sue Jorgensen, another Coast Guard civilian employee responsible for promoting safety on the water, cited the importance of being aware of your surroundings.

"Take a look at what the water is doing maybe a half mile away," said Jorgensen. "[Know] your capabilities, not just of your vessel, but also of your crew."

The same advice goes for landlubbers on their way out to enjoy Juneau's easy access to nature.

Jerry Painter recalled a recent hike he took which began at sea level in warm weather. After his exertions, he was very warm at the top of a mountain. Until, suddenly he was not.

"Even on a warm day, it gets cold if the sun goes behind clouds," said Painter, noting the well-known effects of elevation on temperature. "I almost overdid it."

On his way out the door to begin the search for a lost hiker, Bruce Bowler of Southeast Alaska Dogs Organized for Ground Search had a piece of advice for adventurers in Southeast Alaska. Before leaving for a search, he always pauses a moment to consider what the weather will be like.

"We always check with the U.S. Weather Bureau at their Web site," he said.

The weather bureau Web site, at www.alaska.net/~jnufo, includes the most recent weather predictions, long-range forecasts, and up-to-the-minute data on wind speed and direction at various points around Juneau.

Mary McRae Miller is a freelance writer. She can be contacted at M3@alaska.com

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