Only days away from the end of another miserably dry winter, a private meteorologist revisited the long-term federal forecast — the one made before the winter started.
Maybe you remember the prediction of slightly above-average rain and snow for much of California, says meteorologist Jan Null, a Bay Area weather expert for the last four decades. Reality tells us it missed, rather badly in some places, such as the southern Sierra Nevada.
But this is no knock on NOAA’s Climate Prediction Center. Its forecasters did well in predicting the warm temperatures in California this winter.
The forecasters had other hits and misses around the country. The misses are no big surprise to meteorologists. Folks inside weather prediction circles know that it’s tough to look beyond seven days on a forecast. Nobody can reliably predict December, January and February on Nov. 20, as NOAA tries to do.
“Think of the money you could make if you could do that,” says Null.
Many people talk about the weather influence of El Niño, the warm-water phenomenon in the Pacific Ocean. It does help forecasters shade their bets in some years. But the weak El Niño this year wasn’t much help.
Truth is, there are many ocean-atmosphere cycles going on around the globe. Even knowing about the cycles, science hasn’t been able to reliably sort out what will happen over a three-month period.
At the same time, the federal government has a good reason for continuing and improving this long-range forecast. About a third of the U.S. economy is sensitive to weather, says Null, who testifies as an expert witness in court cases.
Industries and government agencies look at this forecast, trying to get any hint of what’s to come.
Think about your own water supply. Think about farming.
The Sierra Nevada snowpack, which supplies about a third of California’s water, is an anemic 18% of average this year. Any reliable indication last fall of the continuing drought crisis would have been considered golden.
And think about commerce and transportation in New England, which was paralyzed at times by blizzards this year. It was an expensive winter in the Northeast.
New England and the Northeast were probably the biggest misses for the long-range forecast. The forecast said the probabilities pointed to above-average temperatures, but the Northeast shivered from Arctic blasts.
On the other hand, the forecast did pretty well in predicting temperatures in Washington, Southern California and generally west of the Rockies, Null says.
Periodically over the last decade, Null has been comparing the NOAA prediction with reality, just to keep it straight in his own mind. He says he talks with many people who don’t even remember what the forecast was three months ago. But he says he’s trying to help people understand it.
“As I tell classes and audiences when I speak,” Null says, “it’s complicated.”