Late October rains have practically wiped severe drought conditions from the face of Texas maps, and a new weather system is enhancing predictions of a wet El Niño winter, a weather expert says.
Barry Goldsmith, warning coordination meteorologist at the National Weather Service in Brownsville, said that the rare, recordbreaking rain events fueled by Hurricane Patricia will leave Texas with “no significant drought.”
“Hurricane Patricia notwithstanding, El Niño reared its atmospheric head right on cue,” he said. “Other factors were involved, but the second half of October was classic El Niño, with rich moisture from the Gulf of Mexico drenching Texas with efficient rainfall.”
Goldsmith said rainfall is most efficient when it originates deep in the tropics. When such rain falls often enough, it will soak into the soil and enhance reservoirs, lakes, creeks and streams.
“Efficient rainfall is hugely beneficial for agriculture,” he said.
Dr. Juan Anciso, a Texas A&M AgriLife Extension Service fruit and vegetable specialist in Weslaco, said an end to the Texas drought is long overdue, but a wet winter might cause problems.
“There are overwhelming positives to all this rainfall for agriculture statewide,” he said. “The great news is that it ends our drought, conditions the soils, fills reservoirs and limits irrigation. But the flip side is that some crops still out in the fields that got hit by hard rain suffered. Heavy rains for vegetable production here in South Texas, for example, flooded fields, set off plant diseases and ruined some production.”
Anciso said a wet winter in extreme South Texas last year was a serious problem for vegetable production.
“If we have another wet winter in the Rio Grande Valley, it will be another disaster for cabbage, onions and carrots,” he said.
While increased rainfall from the warm waters of a strong El Niño late this year had been predicted, Goldsmith said, another weather pattern called the Pacific Decadal Oscillation, or PDO, will strengthen El Niño’s chances for more efficient rainfall through January at least.
“El Niño patterns that enhance the chance of rainfall can be fleeting,” he said. “But a moderate to strong PDO helps an El Niño maintain and even strengthen its rain-making abilities. And that appears to be what we’re seeing as of late October.”
El Niño refers to warm Pacific Ocean waters in the tropics, while a PDO refers to El Niño-like patterns of climate variability in the mid-latitudes of the Pacific.
Goldsmith said a strong PDO doubles down an El Niño.
“We haven’t seen a PDO of this strength since the mid- to late-1990s, and for El Niño, it’s like having some caffeine, then drinking an energy drink. It’s a double shot. In this case, this PDO will lock down a wetter-than-average Texas from roughly November through February.”
As the season cools, Goldsmith said, it decreases the chance of torrential rainfalls like those seen recently in Willacy County and Wimberley in Hays County.
“The nature of the rain we’re in for later this fall and winter is more gradual,” he said. “Between November and February, we’ll likely see 3 to 5 inches of rain in one or more events somewhere in Texas, but it will take up to several days, not a few hours. We can’t rule out a sudden thunderstorm, but it will be difficult to create a deluge, say 12 inches of rain in four or five hours that quickly floods because it overwhelms drainage systems and can’t flow away.”
Goldsmith said the current El Niño will likely oscillate “back to neutral” in May through July 2016, but chances are high that growers will have little or no need for irrigation water this winter into early spring.
“It’s been said that Texas is in perpetual drought interrupted by the occasional devastating flood,” he said. “Well, this year, 2015, has been wet overall, with our share of occasional devastating floods and unfortunately, dozens of fatalities. But in late October alone, Texas shifted from large areas of extreme and exceptional drought to some areas of abnormally dry, and only a few pockets of moderate drought—a much improved situation.
“Drastic category shifts like that are rare in such a relatively short period of time, but the accumulation and efficiency of the late October rainfall was sufficient for the shift,” Goldsmith said.