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Water + Weather for October 2020 Posted on November 12, 2020


 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 here at the agency. And today, we're going to be taking a look at conditions for our state at the end of October 2020.

Let's start with a look back at September. This is the map of precipitation as a percentage of normal for the month. September wasn't great for West Texas and the Panhandle, where rainfall was well below normal—the reds, oranges, and yellows on this map. But for Central and East Texas, September brought above-average rainfall to many areas—the greens, blues, and purples.

Now, let's look at the same map for October. October rainfall evened things out, but not in a good way. October rainfall was below average for almost the entire state. Only a few scattered areas near Amarillo, west of Wichita falls, and along the Louisiana border received average or more rainfall. The rest of the state received below-average and, in many cases, much below-average rainfall. For example, Midland received three-hundredths of an inch for the month, while San Antonio received twenty-three hundredths. Both those areas and many others in West, Central, and South Texas received less than 10 percent of their normal rainfall for the month.

Overall, a very dry October undid much of the benefit brought by September. Not surprisingly, the U.S. Drought Monitor map for conditions as of October 27 shows a significant increase in drought. September had brought us a 23 percentage point decrease in the area of the state impacted by drought. October bought an 11 percentage point increase. That increase would have been much worse if not for the wet conditions Central and East Texas experienced in September. At the end of October, drought covers 43 percent of the state, including almost all of West Texas and the Panhandle, and growing patches in Central and East Texas. Almost 20 percent of the state is abnormally dry—the yellow areas on this map—indicating they're likely to transition to drought in the next few weeks if rainfall doesn't improve.

What are our chances for improved rainfall and some much-needed drought relief? Not very good. Cooler than normal sea surface temperatures in the eastern equatorial Pacific Ocean, known as La Niña conditions, remain in place and are expected to persist in coming months. These conditions historically bring the southern U.S. and Texas warmer and drier winters and springs. As a result, the National Weather Service is predicting almost all of Texas to be in drought by the end of January 2021.

That concludes our Water and Weather report. In summary, October rainfall was below normal across most of the state. Moderate or worse drought is impacting 43 percent of the state, up from 32 percent at the end of September. Only a relatively wet September for Central and East Texas prevented drought from expanding even more, but La Niña conditions remain in place, and drought is expected to cover most of the state by the end of January 2021. Thanks for viewing. And until next time, I hope you all stay healthy and safe.

This article is posted in Weather / Drought .