Valley’s spring rain, temperature outlook ‘highly uncertain’

Light rain and cold temperatures greet early morning commuters Monday, Jan. 15 2024, in McAllen. (Delcia Lopez | [email protected])
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January turned out to be an “interesting month” in the Rio Grande Valley, with nice weather book-ending a two-week spell of windy, cold and rain between Jan. 8-21.

So observes Barry Goldsmith, warning coordination meteorologist for the National Weather Service Brownsville-RGV station, in a newly released outlook for February-April.

“The highlight of the month was the Jan. 15-17 Arctic outbreak, which brought hard freezes to much of the region on the mornings of (Jan. 16-17),” he said.

February kicks off with a robust El Nino, the climate pattern marked by warmer-than-normal surface waters in the eastern equatorial Pacific, which typically means a drier- and warmer-than-usual in the northern U.S. and Canada but more precipitation and flooding for the Gulf Coast and Southeast.

The higher-than-average rain totals have favored the Florida Peninsula since November, though Texas’ coastal and near-coastal regions have picked up “big rains” most recently, mainly from the Coastal Bend through eastern and southeastern Texas, Goldsmith said.

“Our big rains, Veterans Day weekend in November, continue to dominate the 90-day totals, which generally remain above the long-term average,” he said.

Despite a powerful El Nino going into February, there’s already evidence of a shift toward cooler waters in the central tropical Pacific, which could foreshadow a relatively quick return to neutral conditions — neither El Nino nor La Nina — in the spring, he said. La Nina could kick in by early to mid-summer, Goldsmith said.

La Nina is El Nino’s opposite, characterized by colder waters in the equatorial Pacific and historically causing a drier southern U.S. and heavy rain and flooding in the Pacific Northwest and Canada.

But what’s next for the Valley? Goldsmith said El Nino has snapped back after the mid-January “buckle” in the steering pattern that brought the freeze, and the polar jet stream has “retreated back north of the Arctic Circle,” Goldsmith said.

“For February and perhaps into early March, this means a continuation of fair and seasonable weather, with more clouds than sun overall, with embedded rain events and occasional stronger cooling fronts,” he said. “Exactly how much rain is highly uncertain.”

The closer we get to astronomical spring, which starts on the Spring Equinox (March 19 this year), it’s looking more likely that drier and warmer will become more common, Goldsmith said.

“Finally, severe weather season typically begins in late March and continues through late May, so any atmospheric disturbances moving across the region from the west could lift increasingly warm surface air into thunderstorm clusters or lines that could produce dangerous winds, large hail, frequent lightning and local flooding rains,” he said.

The February-April temperature and rainfall forecast is a toss-up, with equal chances — 33% each — of above average, below average, or average rainfall and temperatures. Based on computer modeling and the transition from El Nino to neutral, current trends suggest “changeable weather in February into March, with a lean toward warmer and drier than average late in March and especially in April,” Goldsmith said.

No widespread, hard freezes are expected in February, though a minor freeze or frost events between mid-February and early March is possible, depending on whether the steering pattern buckles again and sends colder air from southwestern Canada and the northern Rockies down into Texas and northern Mexico, he said.

Meanwhile, water levels at Amistad and Falcon reservoirs remain alarmingly low. In fact, the water storage levels at both reservoirs combined are at a record low for this time of years, Goldsmith said.

“Amistad continues at new record lows, and Falcon is just a shade above the very low levels seen a year ago,” he said. “The forecast through April does not favor sufficient rainfall into watersheds that include tributaries that feed into these reservoirs.”

As a result, the U.S. share of conservation capacity at Amistad-Falcon is expected to remain below 25% “until further notice,” Goldsmith said. The potential for relatively little rain in the Valley, combined with a trend toward warmer/drier-than-average conditions point to possible development of moderate drought — and possibly severe drought — in April, he said.

Given the reservoir situation, it’s essential to conserve water, Goldsmith said.

“This has been a theme for the past two years, and the situation has a potential to get even worse later in 2024 than what we saw in 2022 and 2023,” he said.