Mother Nature sure knows how to throw a curve ball. She can dish out balmy 75 degree weather one day, then switch it up to 107 in a heart beat. Cold and windy comes to the mound next followed by "what’s next?" from the pinch hitter. I hear rumblings about a strong La Nina coming to town this winter. What will this mean to us here in the Santa Cruz mountains? Will it be a dry winter?
To understand major climate trends, scientists collect temperature readings every week from dozens of buoys in the Pacific Ocean. They combine them with satellite images and temperature readings from ships, then plug the data into computer models from scientific agencies around the world.
According to Klaus Wolter of NOAA’s Earth System’s Research Laboratory, water along the equator in the Pacific is currently between 2 – 3.8 degrees Fahrenheit cooler than normal. In extreme La Nina events, it can get up to 7 degrees F cooler.
While a La Nina often allows the Pacific jet stream to trend further northward, bringing increases precipitation to the Pacific Northwest and below normal for So California, across the northern 2/3 of California, there really isn’t a strong precipitation signal in either direction for this event. Northern California is the dividing line between the two extremes and it’s hard to say where exactly that line will fall in any given year. Klaus Wolter contends that we may be subject to notably strong and cold storm systems later this fall but La Nina’s effect on our rainfall is not clear enough for him to draw any definite conclusions.
Jan Null, a former lead forecaster with the National Weather Service who now runs Golden Gate Weather Services in Saratoga, thinks . That’s because in some La Nina years, rainfall has been more plentiful than normal. In one such year, 1999, San Francisco rainfall hit 115 percent of normal.
How’s that for hedging your bets? Just thought you’d want to know the latest predictions for this winter so you can so a little planning!