HARLINGEN — Weather is often unpredictable but it still can be repetitive.
Just as in late 2017, parts of Cameron County are now in moderate drought conditions, which are spreading northward from Brownsville to the outskirts of Harlingen.
“Brownsville and the very southern part of Cameron County are currently in moderate drought and up toward Harlingen it is abnormally dry,” Matthew Brady, a meteorologist with the National Weather Service in Brownsville, said Monday. “As you go further west across the Valley and into Starr and Zapata counties, we actually go from moderate to severe to even extreme drought in Zapata County.”
The latest drought conditions were released last week by the U.S. Drought Monitor.
So far in January, Harlingen has had just 0.29 inches of rain, when the city usually receives 1.06 inches of precipitation. Over the last six months, Harlingen is 4.83 inches below normal when it comes to rainfall.
This is similar to December 2017, when the city saw the 12th-driest October-November period since 1895 and was 5.37 inches below average rainfall for the year.
“A lot of Texas is actually in drought, including most of Deep South Texas,” Brady said. “The only area in our county warning area that is not currently in drought is the northern tip of Kenedy County. The rest of the area is abnormally dry, and we’ve been below normal rainfall not just in January but in December and November as well.
“Zapata, unfortunately, has missed a lot of rainfall in the last six months or so,” he added. “They actually didn’t get too much rainfall during the summer or fall of last year and it just continued into the winter.”
The U.S. Drought Monitor rates drought in categories of abnormally dry, moderate, severe, extreme and exceptional.
All of Willacy County is rated abnormally dry, as is the eastern third of Hidalgo County. The rest of Hidalgo County is in moderate drought.
To the west in Starr County, drought is layered like a cake, with the bottom strip along the Rio Grande abnormally dry, then a layer of moderate drought, a layer of severe drought and then back to moderate in the northeastern third.
All of Zapata County is in severe drought with the exception of the area between the cities of Zapata and Las Lomas where extreme drought conditions persist.
The forecast as to just where all this is headed is, well, cloudy.
“Right now for the three-month outlook from February, March and April, the Climate Prediction Centers is giving us an equal chance for precipitation, meaning we have an equal chance of below or above normal precipitation for those three months,” Brady said. “Nothing definitive there.”
The future of weather in the Rio Grande Valley over the next few months, and the possibility of drought deepening across the region, may be decided by the El Nino-La Nina phenomenon over the Pacific Ocean. A stronger La Nina often means hotter and drier weather here in the Valley, which was what occurred in 2017.
El Nino and La Nina are the warm and cool phases of a recurring climate pattern across the tropical Pacific referred to as the El Nino-Southern Oscillation, or ENSO for short. The pattern can shift back and forth irregularly every two to seven years, and each phase triggers predictable disruptions of temperature, precipitation and wind.
At present, the latest forecast says despite warmer than average waters across the tropical Pacific, forecasters are sticking by their ENSO-neutral prediction for this winter and spring, meaning they don’t believe either El Nino or El Nina will muscle their way to dominance.
“Odds that the warm conditions will mature into a full-blown El Nino event rose slightly between December and January, but not enough to overtake the forecast for neutral,” the NOAA stated in its latest bulletin.
Month Total Average Departure
Jan. 0.29 1.06 -0.77
Dec. 0.96 1.26 -0.68
Nov. 2.75 1.50 +1.25
Oct. 1.63 2.99 -1.36
Sept. 3.55 5.22 -1.67
Aug. 0.26 1.86 -1.60
Note: Average rainfall in city is 27.5 inches annually.
Source: National Weather Service