outlook+water: Big improvements in drought east of I-35, El Niño on the way out (and La Niña in the fall), and last year was the warmest on record

SUMMARY:

• The amount of the state under drought conditions (D1–D4) decreased from five weeks ago at 39% to 23% this week, with drought improvements across much of the state.
• El Niño conditions have a 90% chance of extending through the February-March-April season, giving way to neutral conditions in April-May-June and greater odds of La Niña conditions in the fall.
• Last year was the warmest on record for Texas, a full 3.5 °F warmer than the long-term.

I wrote this article on February 4, 2024.

How about a year in review?

Indeed, last year was the warmest on record in Texas, with the average temp clocking in at 67.9 °F, a full 3.5 °F (1.9 °C) warmer than the long-term (1895 through 2023) average (Figure 1a). Last year continued the ongoing upward swing in temperatures in Texas since about 1975. Similarly, last year was the warmest on record for the planet, in an upward trend that started about 1975 (Figure 1b).

Last year was the third warmest in Austin, tied 2012 for the warmest in Dallas; tied 2018 for the third warmest in El Paso; was the second warmest in Houston, was the second warmest in Lubbock, the warmest in San Antonio; and second warmest in Wichita Falls.

Statewide precipitation was below normal for the second year in a row (Figure 1c). The annual statewide Palmer Drought Severity Index shows that last year was the fifth in a row of overall drought conditions in the state (Figure 1d).

Figure 1a: Twelve-month (January through December) average temperatures in Texas from 1895 through 2023 (data from here).

Over the past month, we’ve had BIG RAIN (10 to 15 inches) fall in the east with little rain (less than half an inch) fall in the west (Figure 2a). The BIG-RAINers got three, four, five, and even six times normal rainfall over the past month, while the little-rainers got half to a quarter or even less than a tenth of normal (Figure 2b). Over the past 90 days, about half the state has received more than normal rainfall while the other half has gotten less than normal rain (Figure 2c).

The amount of the state under drought conditions (D1–D4) decreased from five weeks ago at 39% to 23% this week (Figure 3a), with drought improvements across much of the state (Figure 3b). Extreme drought, or worse, decreased from 6% of the state five weeks ago to 2%, with exceptional drought decreasing from 0.7% to none (Figure 3a). In all, 43% of the state is abnormally dry or worse (D0–D4; Figure 3a), down from 60% five weeks ago.

The North American Drought Monitor, which runs a month behind current conditions, shows drought all around Texas (Figure 4a). Precipitation over much of the Rio Grande watershed in Colorado and New Mexico over the last 90 days was lower than normal, with above-normal rainfall along the river in New Mexico (Figure 4b).

Conservation storage in Elephant Butte Reservoir—an important source of water for the El Paso area—increased to 25.1% full from 23.3% five weeks ago (Figure 4c), slightly above median storage since 1990.

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 Extreme to Exceptional drought (Figure 4a). Combined conservation storage in the Amistad and Falcon reservoirs decreased to 21.8% full from 22.0% five weeks ago, almost 40 percentage points below normal for this time of year (since 1990) and the lowest in at least the past 33 years (Figure 4d).

Basins across the state continue to host flows over the past week below historical 25^th, 10^th, and 5^th percentiles (Figure 5a). Statewide reservoir storage is at 73.3% full, up about 1.4 million acre-feet from 68.9% full five weeks ago and about eight percentage points below normal for this time of year since 1990 (Figure 5b). Recent rains have topped off most of the reservoirs in the eastern part of the state, which are now more than 90% full (Figure 5c).

The reservoir marked in red in the Dallas-Fort Worth area (the raspberry in a sea of blueberries) is New Terrell City Lake and has dropped from full in early March (Figure 5c). I wasn’t able to discern the cause, but I suspect it’s for maintenance on the reservoir and/or dam.

 My (drumroll please) “Hydrograph of the Month” is Lake Travis, due to it missing the rainfall party just to the east of its catchment (Figure 5d).

Sea-surface temperatures in the Central Pacific that, in part, define the status of the weather phenomenon known as the El Niño Southern Oscillation strongly reside in El Niño conditions (Figure 6a). Projections suggest El Niño conditions continuing with a return to neutral conditions in the March-April-May season. This month’s projection is lower than last month’s, suggesting an earlier ending to El Niño. The official probabilities, a month newer than the projections in the graph, give El Niño conditions a 90% chance of extending through the February-March-April season, giving way to favoring neutral conditions in April-May-June and greater odds of La Niña conditions forming in the fall (Figure 6b).

The U.S. Seasonal Drought Outlook through March projects drought persistence in Far West Texas and drought improvement and removal in the Hill Country (Figure 7a).

The three-month temperature outlook projects near-normal temperatures for much of the state except cooler-than-normal temps in West Texas (Figure 7b), while the three-month precipitation outlook favors wetter-than-normal conditions for the eastern half of the state (Figure 7c).