El Nino is developing, and that's good news for SWLA - KPLC 7 News, Lake Charles, Louisiana

El Nino is developing, and that's good news for Southwest Louisiana

Posted: Updated:
(Source: MGN Online) (Source: MGN Online)

Every year, you hear the words El Niño and La Niña thrown around by meteorologists. But what exactly do these mean?

El Niño is when the waters in the Pacific are warmer than normal, while La Niña is the exact opposite: when the waters are cooler than normal. Both have major effects on the Atlantic hurricane season.

Currently, there are warm waters off the coast of Mexico. This is a developing El Niño that stretches all the way into the Pacific Ocean. Across the Atlantic Ocean, and also the Gulf of Mexico and Caribbean, the waters are relatively cooler, and that's good news as we enter this hurricane season.

One of the reasons we forecast an unfavorable environment across the Atlantic during El Niño is because of a subtropical jet stream that develops. That jet stream lifts to the north and rides right across the Gulf of Mexico and the Caribbean which creates an unfavorable upper level environment for hurricanes to thrive.

Also, tropical currents occur, and because of those warmer than normal waters across the Pacific, you get more thunderstorm activity. Those thunderstorms tower into the atmosphere, and that air has to descend somewhere-usually downstream across the Caribbean Sea and also the Gulf of Mexico. The descending air eliminates thunderstorm activity and makes it harder for hurricanes to develop.

"We do believe that El Niño is developing and we expect it to intensify probably becoming a moderate to possibly strong event for the peak of the Atlantic Hurricane season," said Dr. Philip Klotzbach, Research Scientist in Department of Atmospheric Science at Colorado State University.

"Typically when you have El Niños, you get fewer storms in the Atlantic. However it doesn't have as much of an impact in terms of a Gulf coast landfall as it does, say, along the east coast. The Gulf Coast can get, and often does get, significant impacts in El Niño years," Klotzbach added.

One of the things that concerns Gulf Coast residents, especially in Southwest Louisiana, is some of the analog years. One of them, 1957, brought Hurricane Audrey to Southwest Louisiana. Another is 2002 when Hurricane Lili struck central Louisiana.

"These are analog years that overall similar conditions, we don't know what the steering will be and we can't say for sure if we will see another Audrey or Lili. But what we can say is, effectively, the Gulf coast, even if you have a weak of moderate El Niño event, you can still get pretty significant levels of impacts in those areas. Another analog year that we have is 1965, which had Hurricane Betsy which did quite a bit of damage in the New Orleans area," said Klotzbach.

Klotzbach said one of the other big factors we've seen this year is substantial cooling in the tropical Atlantic.

"The Atlantic is actually the coolest it's been since 1994 in the deep tropics. That certainly can change. We saw a big change in those water temperatures last spring which we think is one of the main reasons why we think the season was a lot quieter than we had originally anticipated. Last year we saw the projections were going to be for an above normal season, and that never really panned out. What exactly were the causes for the blown forecast, and are you more confident going ahead into this 2014 hurricane season?"

"We think one of the main reasons we saw this bust was due to the fact we had a lot of cooling maybe not as much in the deep tropics, but in the subtropics, and when the subtropics cool while the deep tropics stayed relatively warm. What that does, it actually causes an increase in the frequency of fronts penetrating into the deep tropics causing more shear and dry air in those areas," said Klotzbach.

As for the forecast this season, Klotzbach recently provided new numbers. They are up slightly from nine named storms he predicted in April to 10 named storms. But that is still below the average of twelve. He is still calling for four of those named storms to become hurricanes. The average is closer to 6 1/2 to seven hurricanes. While he's calling for one major storm, the average is actually two.

El Niño also has another role in our weather-not just impact on hurricanes. It actually creates wet weather across the deep south, especially southwest Louisiana. With regards to the subtropical jet stream that creates wind shear that prevents hurricane formation, it also helps generate more storm systems and wet weather.

Copyright 2014 KPLC. All rights reserved.

Powered by WorldNow