outlook+water: La Niña watch, drought improvements expected, the 20th warmest year (so far)

SUMMARY:

• Drought conditions (D1–D4) increased to 20% of the state from 19% of the state four weeks ago; statewide reservoir storage decreased to 77.3% full from 78.7% four weeks ago, about 4 percentage points below normal for this time of year.
• We are under a La Niña Watch for the fall and winter.
• This is the 20^th warmest year on record in Texas through July.

I wrote this article on September 7, 2025

There’s been a bit of chatter in the press about how mild this summer has been. The rains (and associated fronts) have helped to cool things down from past summers. But how much cooler has it been? My favorite climate aggregator hasn’t yet updated with August numbers, but it shows July as the 72nd warmest on record, which places it just about right in the middle of the 130-year record (Figure 1a). However, taken through July, this is the 20^th warmest year on record so far (Figure 1b). So far this year, the temperature has been 1.9 degrees Fahrenheit warmer than the average from 1901 through 2000. These rankings may go down after August comes in, and September has been schizophrenic (100 degrees one afternoon; 63 degrees one morning).

July’s big purple blob of more than 15 inches in the Hill Country is gone, but August still saw more than 5 inches of rain falling in the region, including over much of East Texas (Figure 2a). About half of the state saw greater-than-normal rainfall, while the other half saw less-than-normal rain (Figure 2b). Substantial parts of South-Central Texas and the Big Bend area received less than 25% of normal rainfall (Figure 2b).

The amount of the state under drought conditions (D1–D4) increased slightly from 19% four weeks ago to 20% today (Figure 3a), with improvements in the Hill Country (Figure 3b). Extreme drought or worse remained at 4% of the state, with exceptional drought decreasing from 0.5% to 0.3% (Figure 3a). In all, 38% of the state is abnormally dry or worse (D0–D4; Figure 3a), up from 28% four weeks ago.

The North American Drought Monitor, which runs a month behind current conditions, shows drought in the American Southwest with smatterings in the northern part of the continent (Figure 4a). The Rio Conchos basin in Mexico, which confluences with the Rio Grande just above Presidio and hosts the largest tributary to the Lower Rio Grande, is now in moderate to extreme drought (Figure 4a).

Conservation storage in Elephant Butte Reservoir—an important source of water for the El Paso area—decreased from 3.8% full four weeks ago to 3.4% more recently (Figure 4b), about 20 percentage points below a rather pitiful median storage of 22% full. Current levels in the reservoir are flirting with lows not seen in at least 35 years.

Combined conservation storage in the Amistad and Falcon reservoirs increased from 25.6% full four weeks ago to 26.2% full today, about 20 percentage points below normal for this time of year (Figure 4c). Storage is on an increasing trend from recent rainfalls, so perhaps we’ll see more storage improvements over the next month.

Basins across the state have continued to experience flows below the historical 25^th, 10^th, and 5^th percentiles over the past week (Figure 5a). Statewide reservoir storage is down from 78.7% full four weeks ago to 77.3% today, about 4 percentage points below normal for this time of year (Figure 5b). The reservoir marked in reddish-orange in the Dallas-Fort Worth area (the persimmon in a sea of blueberries) is New Terrell City Lake and has dropped from full in early March 2024 (Figure 5c). The Lake is no longer used for water supply and appears to be undergoing long-term maintenance work. 

My (drumroll please) “Hydrograph of the Month” is Canyon Lake for how quickly it came up from July rains, but remains much less than normal (Figure 5d).

We are now under a La Niña Watch for the fall-winter season (Figure 6a). If we get one, it sure looks to be a weak one. Neutral conditions are favored for the spring (Figure 6a, b).

The U.S. Seasonal Drought Outlook through August shows drought improvement and removal in Texas (Figure 7a). The three-month temperature outlook projects (surprise, surprise) above-average temperatures for most of the state (Figure 7b) while the three-month precipitation outlook favors below-normal rainfall for most of the state baring the Gulf Coastal Plain (Figure 7c).