Bill Jennings: Don’t let El Nino forecasts curb your skiing zeal
I was coated in dust after riding in a pack of mountain bikers at Riverside State Park last Sunday. Although Mount Spokane received a dusting of its own with a rare storm the week before, its dry brown summit loomed off in the distance. The region’s mountain bike trails – and farmer’s fields – could sure use some rain. But our unseasonably dry weather has done little to dampen the customary surge of anticipation skiers and riders feel this time of year.
Based on the National Weather Service (NWS) forecast, it’s probably raining today. I write this with confidence, because most of the time these guys are right. But after checking the winter weather outlook I’m hoping they could be wrong. There’s always a chance.
Every month the NWS Climate Prediction Center (CPC) publishes the U.S. Seasonal Drought Outlook online. On a map of the U.S., a big ugly brown blob indicating where drought persists or intensifies spreads from southern California to the Canadian border. A yellow blob indicating that drought development likely has grown out of the brown blob covering central Washington to encroach on our neck of the woods.
El Nino, an ocean-atmospheric interaction in the tropical Pacific Ocean that affects global weather patterns, could also be waiting in the wings. The CPC predicts a 67 percent chance that a weak El Nino will start to develop right about now and persist in the northern hemisphere until spring.
Conventional wisdom holds that with El Nino, you can expect a warmer and drier winter than normal. Official normal for temperature and precipitation are the averages recorded during the 30 years from 1981-2010. The CPC drought outlook is valid through the end of January.
Yet even when combined with the emerging El Nino, John Livingston, Head Meteorologist at the NWS in Spokane, said that doesn’t mean you might as well sell your boards and stay home. According to Livingston, the temperature models may be more reliable.
“We’re kind of hedging against the dryer part of the forecast a little bit,” he said. “It is a good bet that when we have an El Nino we will have warmer than normal temperatures through the winter months here in the inland northwest. When we look back at the precipitation for an El Nino it’s a mixed bag.”
Warmer temperatures definitely mean less snow in the valleys, which makes it easier to drive in town. On the mountains there will be snow, but he advised skiers and riders to expect an extra rain event or two through the course of the season.
Livingston said it’s important to understand what the numbers actually mean. According to the three-month outlook for precipitation, the chance of normal is above 40 percent. Near normal precipitation has a one-third chance. Above normal precipitation has a 27 percent chance of happening.
In that case, If Ullr, the mythical Norse god of snow presiding over 49 Degrees North, played baseball, he would be hitting .270 – not too shabby if he can play defense.
In other words, anything can happen.
“While the forecast is certainly possible based on the models and scientific approach, when we look back at the weak to moderate El Nino we’re expecting, in Spokane over past years the precipitation has been all over the place,” Livingston said. “There are years when it is above and years when it’s below.”
The most reliable forecast is for the immediate future. Climatologists hedge their bets more the further out they look. A winter weather outlook written in October could be like the Vegas betting line set in August for who is going to win the Super Bowl. Don’t let El Nino scare you.