The National Weather Service's Climate Prediction Center says we can expect a La Nina winter this season -- La Nina conditions occur when sea surface temperatures in the Pacific Ocean near the equator are running cooler than normal -- and their three-month outlook for November to January predicts above-average precipitation with temperatures right around normal. Still, cautions Meteorologist Ron Miller, not all La Ninas are alike.
"We had three very different results from our last three La Ninas," says Miller, who watches the skies -- and computers -- at the Spokane Weather Forecast Office of the National Weather Service in Airway Heights.
Those three La Nina seasons came consecutively, from late 1998 to early 2001. In 1998-99, Mt. Baker set an all-time record for snowfall, but temps in Spokane turned out to be slightly above average, translating into more rain than snow. In 2000-01, temperatures ran below normal -- we set a record for consecutive days with snow on the ground -- but it was actually a drought year, with less snow than normal in the mountains, Miller says. "So when you say La Ninas mean wetter and colder, that doesn't necessarily mean they occur at the same time in the same winter."
Here in Spokane, our average snowfall is 47.8 inches per season. During the La Nina years of the past half-century, the average has run 58.2 inches -- despite the lower-than-normal snowfall of those last three La Nina seasons. If temperatures run close to normal, as the long-range models predict, then Spokane will likely hover right around the freezing mark during storms.
"Anyone who's lived in Spokane for any length of time knows it's a fine line between rain and snow around here," says Miller. "A lot of our storms are right around the upper 20s, low 30s, so we may start as snow and change to rain, or start as rain and go to snow. It doesn't take much to tip the scales from snow to rain."
But add elevation into the mix, and the odds are better that precipitation will fall as snow. So a forecast of above-average precipitation bodes well for skiers and 'boarders, even if temperatures run close to normal.
"There's no guarantee of tomorrow's weather," Miller quips. But even if you're not a gambler, the odds are looking good. -- ANN M. COLFORD