TUCSON, AZ (Tucson News Now) - El Niño conditions in the Pacific Ocean are now being compared to the 1997-98 El Niño, which is one of the strongest on record since 1950. However NASA cautions against a direct comparison stressing conditions could change between now and October, plus the weather may not react in the same way to El Niño as it did nearly two decades ago.
The maps above show Pacific Ocean conditions in April, May, June, and July of this year. The dark red colors show above-average sea level measurements, which indicates warmer than average sea surface temperatures (SSTs). El Niño is defined by above-average SSTs in the east central Pacific Ocean.
The below image compares the end of July measurements this year to nearly the same day in 1997. As you can see, this year's measurements are more intense than in 1997. In the winter of 1997/98, landslides and heavy rain brought flooding to parts of the west coasts of North and South America. However, just because the set-up is similar doesn't mean weather will be the same. No two El Niño events are alike, plus there is the possibility the conditions could weaken in the coming months. (Although that is not in the forecast, according to the latest computer model runs. In general, El Niño is forecast to remain strong.)
El Niño conditions generally lead to a wet winter in Arizona. However, the increased moisture available from the warmer pool of water in the Pacific Ocean also raises the risk of extreme events. Rather than winter storms spaced out and slowly soaking the desert, rain and snow could instead come in big bursts. This would raise the risk of flooding and do little to alleviate the current drought.