The latest advisory issued by the Climate Prediction Center’s El Nino/Southern Oscillation (ENSO) Diagnostic Discussion states that, as of early September 2009, the El Nino remains weak.
Image from Climate Prediction Center.
I trust that you’ve been reading the blog long enough to understand that the mere presence of an El Nino does not mean much for the upcoming winter; the El Nino needs to be strong in order for fairly predictable and possibly dramatic weather to take place (El Nino is Back in Town).
Will the El Nino Strengthen?
The question then becomes–will the current El Nino strengthen enough to become a significant influence on the weather for the upcoming winter? The Climate Prediction Center (CPC) thinks it will strengthen to at least moderate strength, based on computer model forecasts.
Even a moderate El Nino is not likely to produce the types of weather normally associated with an El Nino (such has heavy rain the Southwest), and if the El Nino were to stay weak, it might have no predictable influence whatsoever.
Winter 2009-2010 Forecast
It appears to me that it’s becoming increasingly less likely that the El Nino will have an overwhelming influence on the weather for the upcoming winter, and that’s something that AccuWeather agreed with when it issued its long-range forecast for the winter (Snowy, Cold Winter on the Way?). I’m not saying the details of that forecast will be correct; however, I don’t think the winter forecast will be as simple as issuing maps that match the typical effects of a strong el nino, which is what I expect most long-range forecasts to be.
–Paul Yeager
