Rainy weather likely to continue through summer



Click through to see other predictions for Texas weather and images of severe storms from weeks past.

Image credit: NOAA The green area indicates higher-than-average rainfall.

Click through to see other predictions for Texas weather and images of severe storms from weeks past.

Image credit: NOAA The green area indicates higher-than-average rainfall. Image 1 of / 368 Caption Close Rainy weather likely to continue through summer 1 / 368 Back to Gallery

Well it's flooding down in Texas, and forecasters say the above-average rainfall will likely continue through summer, and maybe even fall and winter.

The wet weather is largely thanks to a global climate phenomenon called El Niño, which alters global air currents making some regions drier and some wetter. Texas has already felt the effects.

"In many places we've had ridiculous amounts of rain," said state climatologist John Nielsen-Gammon on Friday, before floods swamped Houston on Monday night. "It appears that Texas will easily break its record for single-month rainfall."

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On Thursday, the National Oceanic and Atmospheric Administration released a forecast predicting a Texas summer wetter and cooler than usual. David Unger, a seasonal forecaster with the NOAA climate prediction center, said that forecast is largely based on signs of a strong El Niño this year.

"In general, during an El Niño summer you can expect increased chances for wet conditions in the Texas area," he said.

El Niño happens every two to seven years when parts of the tropical Pacific Ocean get so warm they start heating the air above them. The warm air rises, creating currents that alter the typical flow of the atmosphere and disrupt expected weather worldwide. Some places see weather drier and warmer than average, but Unger said the pattern typically brings more tropical moisture to Texas.

The moist soils associated with the rainy weather would be partly responsible for keeping summer temperatures down as predicted, he said.

But prolonged rainy weather could do damage to places where the ground is already saturated. Many parts of the state have seen three time their average rainfall for May, quickly turning state attention for recent years of scorching drought to coming weeks of potential floods.

In past weeks, flooding prompted mandatory evacuations in Wichita Falls, and in Corpus Christi photos showed cars mostly submerged on low-lying roadways. San Angelo got more than their average rain for the entire month of May in just 45 minutes, according to the Weather Channel. The preceding weeks saw floods across the state as well.

Over the weekend, the swollen Blanco River washed away about 70 houses in Wimberly. Tornados touched down across the state (including one that collapsed a southwest Houston apartment building), and floods hit record heights in Austin and elsewhere.

And on Monday, sotrmclouds dumped over a foot of rain on parts of Harris County, bringing Houston's worst floods since Tropical Storm Allison in 2001.

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Nielsen-Gammon estimated more than 7.5 inches of rain has falled on the state in the past month, beating the previous record of 6.7 inches from June 2004. He said Texas might even beat the two-month rainfall record set in April to May of 1957, when humongous rains brought the state's worst drought on record to an end.

He said predictions of a relatively wet winter don't mean the sky will keep raining like it has. Outbursts like this are fairly typical for May and June, he said, but this one is probably strengthened by El Niño.

And this year the phenomenon may be exceptionally strong. Unger said Pacific surface temperatures rose to threshold levels last year, but El Niño never took hold. To some extent, that warm water hung around. Now the coming El Niño could rival the strongest on record, which played out through 1997 and 1998.

"Many of our models, including some of our better models, are pointing to a considerably strong event," Unger said. "But we think it's a little bit early in the year to make a call."

He said the developing El Niño was a contributing factor to the strong rains Monday night that swamped Houston and other parts of Texas, not a cause.