Posted: Mar 7, 2014 12:20 PM by Meteorologist Josh Eachus
Updated: Mar 7, 2014 12:40 PM
The notorious and often misunderstood climate controlling ocean current, El Niño, is poised for a return this summer. Such an event could have major implications on Louisiana weather and the Atlantic Hurricane Season.
El Niño is the positive phase of the El Niño Southern Oscillation (La Nina is the negative phase), and it occurs when warm water in the Southwestern Pacific spreads eastward along the equator towards the Americas. The whole ENSO cycle tends to reset each year in the spring, making predictability prior to that very difficult.
However, a German research team has designed a method of anticipating ENSO events by evaluating links in air temperatures over the equator and air temperatures over the rest of the Pacific. Their findings offer evidence that there is a 75 percent likelihood of an El Niño developing this year.
With an El Niño likely, an icy winter may be soon forgotten for areas across the north. Warmer sea surface temperatures add heat to the atmosphere, setting the stage for record warmth in many locations around the globe, including the Northwestern United States and Alaska.
Locally, a strengthened subtropical jet stream would mean a cool and wet spring, early summer and winter. Typically, El Niño creates an active storm pattern in the Gulf of Mexico with greater amounts of precipitation and an increased likelihood for severe weather events. During El Niño summers, the weather trends toward a drier pattern with hot temperatures, but not markedly above seasonal averages.
As far as El Niño's impact on the Atlantic Hurricane Season, climate trends are encouraging for the United States. A stronger jet stream increases wind shear in the Atlantic Tropical Basin. Wind shear is a well-known nemesis of hurricanes, as changing wind speeds and direction aloft tend to inhibit storm development and deflects those that do develop away from the United States.
Be sure to check in with the WBRZ weather team to stay up to date on the latest forecasts.