Water + Weather for September 2022 Posted on October 11, 2022
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Dr. Mark Wentzel – Hydrologist, Texas Water Development Board
Hi, everyone, and welcome to the Texas Water Development Board's latest Water and Weather report. I'm Dr. Mark Wentzel, a hydrologist in the Surface Water Division at the agency. And today, we'll be taking a look at conditions for our state at the end of September 2022. Let's take a look at some of the big water and weather headlines.
September was warmer and drier than normal for much of the state, a return to the conditions that prevailed before August. At the end of September, drought conditions covered 61 percent of the state, down 15 percentage points from the end of August but up slightly from a 2022 low of 59 percent achieved in mid-September. Storage in our water supply reservoirs is at about 70 percent of capacity, 11 percentage points below normal for this time of year. Looking forward, drought conditions are expected to gradually expand through the end of the year.
Let's dig into those headlines a little deeper. The dark line on this chart shows how storage in our water supply reservoirs this year compares to minimum, maximum, and median values for the day of the year from data going back to 1990. Also displayed are lighter lines that show how we did in 2021 and 2020 and a red line that shows how we did in 2011. For most of 2022, statewide water supply storage tracked within one or two percentage points of conditions during 2011. That's not a good place to be, as 2011 is considered to be the worst one-year drought statewide since at least 1895. But the above-average rainfall we received in August began to provide some benefit to our reservoirs beginning in mid-August. We are currently running about nine percentage points better than at this time in 2011, but still 11 percentage points less than what is considered normal for this time of year.
What can we expect going forward? Unfortunately, the National Weather Service is expecting a third consecutive fall and winter of La Niña conditions, unusually cool sea surface temperatures in the eastern equatorial Pacific. How does that impact Texas? Typically, La Niña brings below-average precipitation and above-average temperature to Texas during the fall and early winter. For the next several months, we can probably expect about what we got in 2020 and 2021; specifically, below-average rainfall, as shown in the graph on the left, and above-average temperature, as shown in the graph on the right. That combination makes improvement in statewide reservoir and drought conditions unlikely over the next few months. In fact, the National Weather Service is predicting that by the end of December, most of Texas will be back in drought. On a bit longer timeframe, La Niña conditions are expected to dissipate early in 2023. That would be good news for Texas because a return to more average conditions could bring drought relief, if not complete recovery, by the end of next spring. That concludes our report. Until next time, I hope you all stay healthy and safe.