Strong El Niño could bring more flooding to North Texas

With forecasters predicting a strong El Niño continuing through winter, flooding could again pose a problem for North Texas.

The Tarrant Regional Water District, which supplies raw water to most of Tarrant County, is already planning for the possibility, said David Marshall, director of engineering and operations support. With the district’s lakes at a combined capacity of 95 percent, reservoirs wouldn’t have far to go to fill up again.

“Starting late October and into November, we should really begin refilling reservoirs,” Marshall said. “Hopefully, the rain won’t come all at one time so we won’t see any of the damage or destruction like last spring.”

The Climate Prediction Center’s monthly El Niño forecast, released Thursday, said there is a 95 percent chance that El Niño will continue into early spring next year.

While El Niño’s influence is greatest during winter, the climate center’s three-month outlook continues to show above-normal precipitation for most of Texas.

El Niño occurs when sea-surface temperatures are above normal off the Pacific coast of South America, bringing wetter weather to the southern U.S. A strong El Niño could also be a boon to drought-stricken California. The current El Niño is among the strongest on record.

State Climatologist John Nielsen-Gammon said that while El Niño brings no guarantees for Texas, he expects a wetter pattern to return. But even when conditions appear perfectly aligned, it could fizzle.

“It’s possible we could see a good bit of rain, but it’s also possible we could get something really strong and overshoot that sweet spot for rainfall,” Nielsen-Gammon said.

Spring rains

Nielsen-Gammon said he believes North Texas has already felt the effects of this El Niño and points to May’s record rainfall and flooding.

“I have research showing that when you come into an El Niño, you can get very heavy rainfall during the spring,” he said.

In winter 1997-98, which is considered one of the strongest El Niño seasons on record, Dallas-Fort Worth had its second-wettest winter (December-February) on record, with 15.22 inches.

“It does appear that precipitation amounts increase with increasing strength of El Niño,” National Weather Service meteorologist Dan Huckaby said.

But Huckaby said there have been only five strong El Niño events since data started being tracked for this type of weather phenomenon in North Texas.

“There are only five good analogs for this coming winter,” Huckaby said. “Using these as predictors might be helpful, but there is certainly no statistical significance.”

Rain way above normal

Fall is traditionally one of the wettest seasons in North Texas, and Wednesday’s storms dumped a record 2 inches at Dallas/Fort Worth Airport.

This year, the airport has had 38.96 inches of rain — 13.9 inches above normal.

Because most of the rain came in the spring, drought conditions have crept back into parts of Texas. Sections of Tarrant, Dallas, Denton and Wise counties are listed in severe drought. And some areas southeast of Dallas are listed in extreme drought, the second-worst category.

The latest drought monitor, released Thursday, doesn’t include Wednesday’s rain.

In the short term, North Texas should cool off this weekend with its first hint of fall-like temperatures, with highs in the mid-80s.

Highs will climb back into the 90s next week, but no 100-degree days are on the horizon.

“It’s not out of the question that we could see another 100-degree day, but a lot of the long-range guidance is suggesting we’re probably done,” said Matt Stalley, a meteorologist with the weather service.

This year, North Texas has had 15 days of at least 100 degrees, the same number as last year and three below the average of 18.

El Niño winters also tend to be cooler, but Huckaby said that doesn’t mean North Texas will see more wintry weather.

“It turns out that extreme cold outbreaks are actually less likely during El Niño winters, which typically have fewer days with freezing temperatures than normal,” Huckaby said.

This story was originally published September 11, 2015 at 10:58 AM with the headline "Strong El Niño could bring more flooding to North Texas."