SUMMARY:
- Drought down (but not out), with 61% of the state abnormally dry or worse.
- The Climate Prediction Center’s El Niño Watch continues with a 90% chance of El Niño conditions forming during May-June-July.
- Warmer-than-normal conditions are expected for the entire state, with normal rainfall for everyone except Far West Texas, where drier-than-normal conditions are expected.
I wrote this article on May 29, 2023.
Some months I struggle for something to write here, while others, I am cats-and-dogs with topics. This month we’ve got NOAA’s hurricane predictions, the Farmers’ Almanac’s projections, and an expected bump in global temperatures this year.
Last month I wrote about Colorado State University, which projects the Atlantic hurricane season will be slightly below average with 13 named storms and six hurricanes, two of which might be major. NOAA projects a near-normal Atlantic season with 12 to 17 named storms, 5 to 9 hurricanes, and 1 to 4 major hurricanes (Figure 1a). El Niño tends to suppress tropical storm development due to shearing winds, so the season is in a race against El Niño conditions and the question of how strong the expected Niño will be.
The Farmers’ Almanac projects a warmer-than-normal summer, a projection “based on a proprietary formula that relies on many factors, including the Moon.” For our neck of the country, the Almanac predicts sweltering temperatures and “tons of thunderstorms” (we’re definitely seeing the latter; Figure 1b). The Farmers’ hurricane outlook “suggests a hurricane threat from the Gulf Coastal States northeast to the mid-Atlantic Coast sometime in the third week of August.”
Many are predicting a blistering year for the planet. In large part, this is driven by the transition out of three years of La Niña conditions because there’s not as much evaporation from the Pacific Ocean’s surface during La Niñas (the cooling phase of the El Niño Southern Oscillation). During El Niños, however, sea surface temperatures warm, thus increasing evaporation and the transfer of energy to the atmosphere. When evaporated water condenses to form clouds, condensation releases heat and thus warms the atmosphere. Therefore, the coolest year during a decade tends to be a La Niña, and the warmest tends to be El Niño (Figure 1c). So, the amount of warming this year also depends on how strong the projected El Niño is. In short, “The Child” will dictate what kind of weather year we have this year.
Figure 1a: Forecast for 2023 Atlantic Hurricane Activity by NOAA (from NOAA).
Figure 1b: Forecast for 2023 by the Farmer’s Almanac (from the Farmer’s Almanac).
Figure 1c: Global surface temperature since the 1950s with La Niñas and El Niños marked (from NOAA).
Over the past 30 days, a large part of the state saw more than 5 inches of rain, while Far West Texas saw less than an inch (Figure 2a). Much of the state saw 1.5 times more normal rainfall over the last month, with less than normal amounts falling in the northeast, a part of South Texas, and the aforementioned Far West Texas (Figure 2b). Rain over the past 90 days—a big driver for drought conditions—remains below normal for almost the entire western two-thirds of the state, with large areas in West and Far West Texas receiving less than 50% of normal (Figure 2c).
Figure 2a: Inches of precipitation that fell in Texas 30 days before May 29, 2023 (modified from the National Weather Service). Note that cooler colors indicate lower values, and warmer indicate higher values. Light grey is no detectable precipitation.
Figure 2b: Rainfall as a percent of normal for the 30 days before May 29, 2023 (modified from the National Weather Service).
Figure 2c: Rainfall as a percent of normal for the 90 days before May 29, 2023 (modified from the National Weather Service).
The amount of the state under drought conditions (D1–D4) dropped considerably from four weeks ago at 58% to 42% this week (Figure 3a), with drought intensity decreasing across most of the state (Figure 3b). Extreme drought or worse decreased from 18% of the state four weeks ago to 9%, with exceptional drought decreasing from 4.1% to 0.5% (Figure 3a). In all, 61% of the state remains abnormally dry or worse (D0–D4; Figure 3a), down from 78% four weeks ago.
Figure 3a: Drought conditions in Texas according to the U.S. Drought Monitor (as of May 23, 2023; from the U.S. Drought Monitor).
Figure 3b: Changes in the U.S. Drought Monitor for Texas between April 25, 2023, and May 23, 2023 (from the U.S. Drought Monitor).
The North American Drought Monitor, which runs a month behind, shows drought focused over the Great Plains and much of Mexico (Figure 4a). Precipitation over much of the Rio Grande watershed in Colorado and New Mexico over the last 90 days was lower than normal, but there were small areas with normal to above normal precipitation (Figure 4b).
Conservation storage in Elephant Butte Reservoir—an important source of water for the El Paso area—increased to 26.2% full from 19.1% four weeks ago (Figure 4c), just a nudge below median storage since 1990.
The Rio Conchos basin in Mexico, which confluences with the Rio Grande just above Presidio and is the largest tributary to the Lower Rio Grande, remains abnormally dry in the mountains but drought-free for most of the basin (Figure 4a). Combined conservation storage in the Amistad and Falcon reservoirs increased to 30.2% full from 27.6% four weeks ago, still about 30 percentage points below normal for this time of year and below the lowest low for this time of year recorded since 1990 (Figure 4d).
Figure 4a: The North American Drought Monitor for April 30, 2023 (from the U.S. Drought Monitor).
Figure 4b: Percent of normal precipitation for Colorado and New Mexico 90 days before May 29, 2023 (modified from the National Weather Service). The red line is the Rio Grande Basin. I use this map to see check precipitation trends in the headwaters of the Rio Grande in southern Colorado, the main source of water to Elephant Butte Reservoir downstream.
Figure 4c: Reservoir storage in Elephant Butte Reservoir since 2021 with the median, min, and max for measurements from 1990 through 2022 (graph from Texas Water Development Board).
Figure 4d: Reservoir storage in Amistad and Falcon reservoirs since 2021 with the median, min, and max for measurements from 1990 through 2022 (graph from the Texas Water Development Board).
Basins across the state continue to have flows over the past week below historical 25th, 10th, and 5th flow percentiles (Figure 5a). Statewide reservoir storage is at 76.8% full as of May 29, up about 510,000 acre-feet from 75.2% four weeks ago and about eight percentage points below normal for this time of year (Figure 5b). Most reservoirs in the eastern part of the state have recovered to more than 90% full, with just a few less than 90% full (Figure 5c). The “light blue” reservoir northeast of Dallas (between 70 and 80% full) is accurately but perhaps unfairly that color since it, Bois D’Arc Lake, is a relative newborn and just started its initial inundation last year (Figure 5c).
New Terrell City Lake is the reservoir marked in red in Dallas-Fort Worth (the raspberry in a sea of blueberries). It has dropped from full in early March to about 25% today (Figure 5c). I couldn’t discern the cause, but I suspect it’s for work on the reservoir and/or dam.
I’ve written about low levels in Lake Waco over the past year, so it’s good to report that recent rains and runoffs have brought reservoir levels back up to previous historic lows (Figure 5d). Things could be better, but at least things are moving in the right direction (up!).
Figure 5a: Parts of the state with below-25th-percentile seven-day average streamflow as of May 28, 2023 (map modified from U.S. Geological Survey).
Figure 5b: Statewide reservoir storage since 2021 compared to statistics (median, min, and max) for statewide storage from 1990 through 2022 (graph from Texas Water Development Board).
Figure 5c: Reservoir storage as of May 29, 2023, in the major reservoirs of the state (modified from Texas Water Development Board).
Figure 5d: Hydrograph of the Month—Reservoir storage for Waco Lake (graph from Texas Water Development Board).
Sea-surface temperatures in the Central Pacific that, in part, define the status of the El Niño Southern Oscillation, reside in neutral conditions (Figure 6a). However, models and experts believe we will enter El Niño conditions over the next couple of months, so we are under an El Niño Watch with a 90% chance of El Niño continuing into the winter. This month’s expert (consolidated) projection hugs the lower regions of the plume of models, suggesting a weak El Niño (Figure 6a). However, the official probabilities, a month newer than the model projections, give El Nino conditions an 80% chance during May-June-July with more than a 90% chance from late summer through the end of the year (Figure 6b).
Figure 6a. Forecasts of sea-surface temperature anomalies for the Niño 3.4 Region as of April 19, 2023 (modified from Climate Prediction Center and others). “Range of model predictions -1” is the range of the various statistical and dynamical models’ projections minus the most outlying upper and lower projections. Sometimes those predictive models get a little craycray.
Figure 6b. Probabilistic forecasts of El Niño, La Niña, and La Nada (neutral) conditions (graph from Climate Prediction Center and others).
The U.S. Seasonal Drought Outlook through August 2023 shows drought persisting over much of the western two-thirds of the state (Figure 7a). Like a broken record, the three-month temperature outlook projects warmer-than-normal conditions for the entire state (Figure 7b), while the three-month precipitation outlook favors normal conditions for most of the state except for Far West Texas, where drier-than-normal conditions are expected (Figure 7c).
Figure 7a: The U.S. Seasonal Drought Outlook for May 18, 2023, through August 31, 2023 (from NOAA).
Figure 7b: Three-month temperature outlook for June-July-August 2023 (from the National Weather Service).
Figure 7c: Three-month precipitation outlook for June-July-August 2023 (from the National Weather Service).