As El Niño Fades, Expect Warmer And Drier Weather
May 6, 2016
The current El Niño that has lasted since summer of 2015 is on its way out and after one of the warmest winters on record in Texas, that could change weather patterns in the next few months, says Texas A&M University professor and State Climatologist John Nielsen-Gammon.
It’s believed the El Niño – warm waters in the central Pacific Ocean — has been responsible for above-average rainfall over much of Texas and the Southwest the past year, and it’s almost certain it will be replaced by a La Niña – cooler waters in the central Pacific that also influence weather, but in different ways, Nielsen-Gammon says.
“The tropical Pacific temperatures are almost certain to continue to decline,” Nielsen-Gammon says.
“A tongue of cooler-than-normal temperatures has been working its way eastward across the Tropics just below the surface of the ocean, and it has now reached South America. Those cooler waters will continue to spread across the surface of the ocean as the warmer water moves westward, back toward New Guinea and Indonesia.
“What that means is that it still seems likely that temperatures will cool enough to reach La Niña territory by late summer or fall. The Climate Prediction Center rates the chances of a La Niña at about 75 percent. By next winter, if La Niña is in place, Texas is likely to experience a warm and dry winter.”
He notes that the past six months were typical for an El Niño in some ways and atypical in others.
Although there was a dry stretch in January and February, the six-month period November through April was the 7th wettest November-April on record statewide, with records going back to 1895. The extremely wet October of 2015 in Texas actually makes the October-April period the wettest October-April period on record, his figures show.
But the rainfall was not evenly distributed across Texas. Many parts of west-central, north-central, and northeast Texas received more than double their normal precipitation for November through April, while parts of the Coastal Bend and much of the Texas Panhandle and High Plains received less than normal precipitation.
“Though above-normal rainfall is common during an El Niño, above-normal temperatures are not common,” he points out.
“Usually temperatures are below normal during an El Niño, though that effect has been moderated somewhat by global warming. This year, though, many cities across the state, from Amarillo to Brownsville and El Paso to Beaumont, experienced one of their 10 warmest cool seasons (November-April) on record. Midland-Odessa came closest to setting a record — their average temperature was 54.8 degrees, second only to the year 2000.”
Cold weather was mostly a no-show and winter this year was almost non-existent in many parts of Texas.
“The temperature only got down to 22 degrees in Abilene, 27 degrees in Dallas, 30 in San Antonio, 31 in urban Austin and 40 in Galveston. All of these were new records for mildness, with weather records going back for more than a century in most locations,” Nielsen-Gammon explains.
Unlike winter weather in Texas, which is strongly affected by El Niño and La Niña, the weather during the summer is difficult to predict far in advance.
Nielsen-Gammon says the wet weather this winter will help keep summer temperatures on the mild side, especially during the early part of the summer. In late summer, attention turns to the danger of hurricanes making landfall in Texas.
“For hurricanes, the key will be how quickly La Niña develops in the tropical Pacific,” he says. “The sooner La Niña forms, the more active the Atlantic hurricane season is likely to be. Even so, Texas is a small target, so an active hurricane season across the entire Atlantic would not necessarily mean one or more landfalls in Texas itself.”