Ever heard of the phrase 'a little bit of knowledge can be a dangerous thing'? Without pointing fingers, it seems like thousands of expert long-term weather forecasters have suddenly emerged from out of nowhere. Every one of them seems to be an expert in El Ninos and La Ninas, weather terms long-term forecasting pioneers first began to understand barely more than half a century ago. The terms surfaced in some publications in an attempt to explain the devastating drought in 1983, but still remained far from household words on farms across the country.
Suddenly they're bantered about like everyone knows what they mean. And more than that, those using the term seem to assume an arrogance that portrays complete understanding of how they work. Yet the comments and forecasts many of those same people make based on their so-called understanding of El Nino cycles leaves true believers and students of long-term weather forecasting scratching their head.
Case in point: late last August the weather suddenly turned cool. Within a week a long-time weather forecaster was saying, 'see, we're already feeling the effect of El Nino.' No bother that the weather soon changed to a different pattern. And just recently some private weather and crop forecasting companies have heralded the death of the current El Nino, proclaiming it won't be an El Nino summer after all. Some even are fretting over La Nina, the cool phase, starting up by mid to late summer, maybe bringing drought.
What these forecasters are missing is the dynamics of how long-term influencing factors affect weather patterns, notes Jim Newman, retired ag climatologist. Newman was one of the early pioneers of El Nino cycles in the 50's and 60's, and has spent decades meticulously unraveling how these cycles work, and the clues they can impart for upcoming weather patterns around the globe.
These cycles, like most things that affect long-term weather, move slowly. Lag time can be up to three months. That means that once a new cycle actually begins, it can be weeks if not months before the effects are felt in the mid-latitude, including the Corn Belt and Great Plains in the U.S.
"El Nino, the warm phase, peaked in January and February," he says. That's a far cry form the death knell some services issued in mid-January.
"It will die out this spring," he continues. "That would make it about a year-long event. It's not that short-in fact, it's fairly normal. We definitely saw an impact of El Nino on winter weather. The cold west coast and freeze problems with California citrus stem from it."
The irony is that although some of the commercial forecasts seem to incorrectly interpret the movements of the El Nino cycle, many are arriving at about the same forecast as Newman and many other long-term forecasting agencies for spring '07. "It will be warm in the Pacific where it's cold now," Newman says. "Look for it to be cold in the northeast and into Canada. The Midwest will likely have normal rainfall, but it may be a bit of a delayed spring. There will be a cold period sometime in the late March through early may time frame."
Moisture could wind up above normal as well before spring is over in the Midwest. Summer is still a bit of a question mark, Newman says. "El Nino will die out, but won't be completely gone until late summer. So we don't expect that the influence of El Nino on summer weather will be very strong."
While this El Nino is average in length, it will go down as a mild episode. "It never was very intense," Newman observes. Water temperatures far out in the tropical Pacific were only about 2 degrees F above normal at the peak of the event. In intense El Ninos they can rise to three to four degrees above normal.
For those worried about man-made climate change, at least one event this winter held true to form. "We've never had a winter where it was cold continuously in both California and Florida at the same time," he says. "That trend goes back 100 years. It's never happened, and it didn't happen again this year. Florida was spared the below normal winter trends that plagued fruit growers in California."