FORECASTS—L.A. forecasting isn’t so easy

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Tune into one local newscast and you will find the day’s temperature expected to hit 82. If that’s too hot, just change the channel, where the forecast high is 81. Keep going and you’ll hit a third insisting that it won’t get out of the 70s.

L.A. weather is a lot trickier to figure out than Easterners might think. OK, so it’s rare to see an edge of thunderstorms race across the region on a hot summer afternoon like it does in Florida. But subtle stuff happens and with almost every degree making a difference in whether your power goes on or off this summer, TV weathercasts are receiving greater-than-usual scrutiny.

Too bad they’re often all over the map.

“Forecasts that are provided in the newspapers and on television are very broad and quite vague,” said Michael Root, executive vice president of WeatherBank Inc., a weather-forecasting company in Oklahoma. In a place like Southern California, where cool offshore breezes can take unexpected zigs and zags, broad and vague are not enough.

To be fair, stations have beefed up their weather departments sometimes to include meteorologists who work behind the cameras to decipher a maze of satellite images and computer models from both the National Weather Service and private weather services. From this, they each come up with their own forecasts, which helps explain the variation in temperature.

“The news directors are wanting that,” Stephanie Kenitzer, a spokeswoman for the American Meteorological Society, said of the push for full-fledged meteorologists “It lends credibility to the weather segment.”

Why all the fuss? Because even in a place like L.A., viewers love watching the weather. Next to traffic reports, of course.

Dallas Raines, a local meteorologist and weather broadcaster, said he routinely updates his forecasts for each of three daily reports he does on KABC Channel 7.

“People are looking each day at the five-day forecast to see when they’re going to have to have their (air conditioners) on,” said Raines. “We try to tell people what’s coming.”

Weather anchor Maria Quiban of KCOP Channel 13 said she consults several sources, including a private forecasting service, and then develops her own forecast.

Temperatures in one report may vary from another depending on the cities and weather sources, said Quiban, who has been a weather broadcaster for six years and is working toward a degree in meteorology. “There are so many different weather services,” she said. “I’m seeing different information.”

Why the variation? “There’s no simple answer,” said David Danielson, science and operations officer for the National Weather Service in Oxnard.

Weather forecasting depends on numerical models, which are based on a lot of assumptions. Add to that the fact that forecasters can get climatic information from numerous sources. In turn, the data may be interpreted differently by in-house meteorologists.

Making things tougher is the area’s complicated topography.

“The terrain in Southern California…is probably some of the most complex terrain in the United States,” Danielson said. “You’ve got everything there. You’ve got mountains, desert, islands, forests.”

That means temperature levels, humidity and other weather conditions can change dramatically from one city to the next. “You can be 68 (degrees) at the beaches and 108 (degrees) in Lancaster on the same day,” Danielson said.

Raines, who has done the weather for several stations around the country, says L.A. is among the toughest place to forecast. “You think about Southern California, that it would be really easy,” he said. “But, there are times when we are just overwhelmed by all of these little microclimates.”

An L.A. forecaster’s woes don’t end there.

Atmospheric conditions move from west to east. With the Pacific Ocean to the west of Southern California, Raines said meteorologists must rely on information provided by satellite, as opposed to radar or weather balloons, which are more accurate.

Though Raines claims to be up to 95-percent accurate in his 24-hour forecasts, he doesn’t fault the public for being skeptical.

“On a Sunday, for instance, you have an outdoor barbecue and it rains, and they never quite forget that,” he said. “We try out best to get it right every time.”

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