Question of the Day - 09 October 2023

Forecasters seem pretty confident that this winter will be subject to the so-called El Niño weather phenomenon, which they identified as starting to develop as far back as late spring.

El Niño is associated with ocean water that warms up more than usual in the central and east-central Pacific, generally along a band at the equator, thus off the Pacific coast of South America. Known as the Southern Oscillation, it's a complicated pattern of warm and cold surface sea temperatures and high and low air-pressure fronts that can, depending on severity, have worldwide effects on weather. El Niño also alternates with the so-called La Niña cycle; it's unclear how long the patterns last, but it's generally believed they range from two to seven years. 

Then there are fluctuations in the strength of the cycles. At the moment, the El Niño is brewing in the central Pacific, but so far its intensity is in question. 

As far as southern Nevada is concerned, El Niño is associated with unusually heavy moisture that spreads from California throughout the Southwest. But the long-range local forecasts we've seen are inconclusive; though warmer temperatures are predicted, the models show "equal chances for above or below normal precipitation." That said, other models from around the world are warning of a "super El Niño," such as the historic pattern in the winter of 1997-1998. Las Vegas experienced the wettest February in its history during February 1998: just under three inches of rain and snow. Normally, February sees three-quarters of an inch; year-long, the average is a little more than four inches.

Whichever way it goes, the effects on the continental U.S. are strongest between December and February, though they can extend into late March-early April. 

As we say, the jury is out for us locally as far as precipitation is concerned. And it's essentially the same for temperatures being above normal.

Bottom line: It's still too early to tell, but we'll keep our eye on it and report developments as they occur.