We are officially in an El Niño Advisory. That’s according to scientists with NOAA’s Climate Prediction Center. This means water along the equatorial Pacific is warmer than normal which changes our weather patterns across the globe for potentially many seasons to come.
El Niño is a part of the El Niño Southern Oscillation (ENSO) which is a reoccurring climate pattern characterized by the water temperatures along the equatorial Pacific. When the sea surface temperatures are normal or near-normal, it is considered the ENSO neutral phase. Cooler than normal water (at or below .5° C colder) means a La Niña phase is likely present while warmer than normal water (at or above .5° C warmer) characterizes the El Niño phase.
What is an El Niño Advisory?
The changing trade winds along the equatorial Pacific cause the water to turn cooler or warmer than normal. In the case of the El Niño pattern, the trade winds have weakened which has pushed warmer than normal water towards the central and eastern equatorial Pacific. An El Niño Advisory means the water has been warmer than normal for about a month and is expected to stay that way for several seasons ahead. It also means there has been a notable change in the weather right above the warmer water where a rainier pattern has now set up.
Typically, an El Niño pattern will create more wind shear in the Atlantic basin. More wind shear means less tropical development. But this year we have warmer than normal sea surface temperatures in the Atlantic basin. Warmer than normal water is a driving factor for increased tropical activity.
Even though the record warm water can increase tropical activity, wind shear from the El Nino pattern can make it harder for tropical development. These two factors will be competing this hurricane season.
Both NOAA and Colorado State University have given near-normal projections in their seasonal hurricane outlooks. They cite the El Nino conditions and competing record warm Atlantic basin for their projections.
How long will the El Niño pattern last?
An El Niño pattern typically lasts between 9 and 12 months and occurs on average every 2 to 7 years. It usually starts in May or June and peaks during winter and early spring.
Climate models are showing that not only will this El Niño pattern stick around, but it’s expected to strengthen this winter. A typical El Niño winter is cooler and wetter for the Gulf states. But it’s important to remember that no two El Niño patterns are alike so there isn’t a guaranteed weather outlook. Just that the odds increase for certain atmospheric set-ups.