The weather is getting worse, says one expert.

Torrential rains fall in the Houston area more often than they used to, according to an unpublished analysis from state climatologist John Nielsen-Gammon.

Heavy precipitation of any particular magnitude are twice as likely to fall in the Bayou City today as they were in the early 20th Century. Downpours that struck every two years back then come every year on average now. Deluges that used to drop each 100, 500 or 1000 years should fall more frequently as well.

Nielsen-Gammon, a climate scientist at Texas A&M University who was appointed state climatologist by Gov. George W. Bush in 2000, reviewed data from rainfall gauges across the state, some with records dating to the late 19th Century. For Harris County, he drew from 17 gauges.

"We've confirmed that there's an overall increase in extreme rainfall in Texas over the past century," he said. "Specifically for Houston the increase has been particularly large."

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That spells trouble for a city already plagued by crippling floods, where urban sprawl has overwhelmed the waterways that drain the city, and dense development has precluded their expansion.

Nielsen-Gammon's findings fall in line with a trend that was theorized decades ago and first emerged in scientific data near the turn of the 21st Century. Nielsen-Gammon said he took the first fine scale look at data across different parts of the state.

"He's probably spot on," said veteran Rice University climate scientist Ron Sass, when presented with a summary of Nielsen-Gammon's findings. "He's as close to the truth as I've seen."

An independent analysis of local rainfall data from the National Weather Service also confirmed the state climatologist's findings. Of the 100 rainiest days in Houston since 1890, as measured at multiple gauge sites, the wettest of the wet are skewed dramatically towards the last four decades.

The Houston area just had its wettest April on record, and some storm gauges during the Tax Day flood registered levels beyond what are expected once every century. But it was an exceptional season.

Texas rains in 2015 and 2016 got a boost from El Niño, a periodic global climate phenomenon that expectedly brings wetter-than-average weather to the Lone Star State. The current El Niño rivaled the strongest on record, which were observed in 1982-83 and again in 1997-98.

As the phenomenon subsides for now, Texas should get some respite from the torrential downpours.

In fact, Texas is likely headed for a period of drier weather, said Jake Crouch, a climate scientist with the National Oceanographic and Atmospheric Association. El Niño's counterpart is expected to develop, and it typically brings with prolonged dry weather in Texas (and an active Atlantic hurricane season).

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Such has been the norm here through recent decades: a record drought in 1996 was washed away by a record El Niño in '97, and the La Niña that followed put the state back in drought.

A big drought in 2006 ended with one of the state's wettest years on record in 2007.

The state's recent scathing drought kicked off during La Niña with its driest year on record in 2011 and persisted painfully until El Niño made 2015 Texas' wettest year on record.

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"This trend doesn't mean we're going to see a steady increase in precipitation going forward," Crouch said. "The way we are receiving our precipitation is changing. We're seeing more of that precipitation fall in single events."

It shouldn't take anyone by surprise. Scientists in the 1970s calculated that intense rains would become more intense as a warming atmosphere evaporated more water and held it in the air. A federal report in 2009 presented the first data to demonstrate that the trend was manifesting.

Satellite data from NASA's Goddard Institute and other agencies show the global temperature average has increased by about one degree Fahrenheit since record keeping began in earnest around 1880. NASA data showed that 2014 had become the warmest year on record for Earth, only to be outdone by 2015.

"When the warmer air with more water vapor is in a meteorological situation producing rain, the rain tends to come in more extreme events, with heavier rains," said former NASA scientist James Hansen. "So the 'hundred-year-flood' now occurs more than once a century."

In places far from atmospheric vapor flows, the warmer air exacerbates drought, Hansen said.

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The increase in dramatic downpours was more than twice as pronounced in the Houston area as in most parts of Texas. In the surrounding counties of Brazoria, Fort Bend and Galveston, the frequency of torrential rainfall increased only minimally, or sometimes decreased. Nielson-Gammon called that discrepancy "probably random, but maybe not."

All experts queried expected the trend to continue, even as the region weathers wet and dry periods. When global patterns bring a wet spell back to Texas, it could be worse than the record breaking stretch since spring 2015.

Nielsen-Gammon said he is strongly considering developing his research into an academic paper.