outlook + water

outlook + water: February 2019

SUMMARY:

  • El Niño is here! El Niño is here!
  • Abnormally dry conditions have spread across much of West, Far West, and South Texas.
  • Precipitation in the headwaters of the Rio Grande on Colorado continues to remain at 25 to 50 percent of normal.

The weather sure has been schizophrenic this past month. Austin started last week with freezing temperatures and ended with a record high of 91. Before that, we learned about graupel (when supercooled water freezes onto snowflakes) after being gently pelleted by the stuff. On any given morning, I’m not sure if I should head out with a winter coat or swimming trunks.

Precipitation over the past 30 days has ranged from nothing in small parts of West and Far West Texas to almost 6 inches in East Texas. Most of the state received less than normal amounts of precipitation with much of the High Plains receiving less than 25 percent of normal during this time period.

Figure 1: Inches of precipitation that fell in Texas in the 30 days before February 20, 2019 (source).

Figure 1: Inches of precipitation that fell in Texas in the 30 days before February 20, 2019 (source).

The amount of drought in Texas (D1-D4) over the past month increased from 0.8 to 3.1 percent with patches of moderate drought appearing in the Panhandle, the Trans-Pecos, and the Lower Rio Grande Valley and now in south Texas (Figure 2a). Abnormally dry conditions or worse expanded across West Texas, the Trans-Pecos, and South Texas from 9.6 percent a month ago to 35 percent (Figure 2b).

Figure 2a: Drought conditions in Texas according to the U.S. Drought Monitor (as of February 12, 2019; source).

Figure 2a: Drought conditions in Texas according to the U.S. Drought Monitor (as of February 12, 2019; source).

Figure 2b: Changes in the U.S. Drought Monitor for Texas between January 15, 2019, and February 12, 2019 (source).

Figure 2b: Changes in the U.S. Drought Monitor for Texas between January 15, 2019, and February 12, 2019 (source).

The 90-day precipitation as a percent of normal is showing deficits in large parts of the state in the High Plains, the Trans Pecos, and much of the Rio Grande Valley (Figure 3).

Figure 3: Rainfall as a percent of normal for the past 90 days (as of February 20, 2019; source).

Figure 3: Rainfall as a percent of normal for the past 90 days (as of February 20, 2019; source).

The North American Drought Monitor for the end of January shows extreme to exceptional drought in the headwaters of the Rio Grande, which doesn’t bode well for reservoir levels in Elephant Butte (Figure 4a). Precipitation in the Rio Grande watershed in Colorado, the primary source of water for Elephant Butte Reservoir, continues to be than 50 percent, and in many areas less than 25 percent, of normal precipitation over the past 90 days (Figure 4b).

Figure 4a: The North American Drought Monitor for January (source).

Figure 4a: The North American Drought Monitor for January (source).

Figure 4b: Percent of normal precipitation for the past 90 days for Colorado and New Mexico as of February 20, 2019 (source). 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 4b: Percent of normal precipitation for the past 90 days for Colorado and New Mexico as of February 20, 2019 (source). 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.

Statewide reservoir storage has been about 90 percent full since mid-November and is about 8 percentage points above normal for this time of year (Figure 5a). Percent full status for individual reservoirs this month (Figure 5b) is about the same as last month (Figure 5c).

Figure 5a: Statewide reservoir storage since 2017 compared to statistics (median, min, and max) for statewide storage since 1990 (source).

Figure 5a: Statewide reservoir storage since 2017 compared to statistics (median, min, and max) for statewide storage since 1990 (source).

Figure 5b: Reservoir storage as February 20, 2019, in the major reservoirs of the state (source).

Figure 5b: Reservoir storage as February 20, 2019, in the major reservoirs of the state (source).

Figure 5c: Reservoir storage as January 25, 2019, in the major reservoirs of the state (source).

Figure 5c: Reservoir storage as January 25, 2019, in the major reservoirs of the state (source).

After sea surface temperatures achieved El Niño levels for the past several months, the warming finally coupled with the atmosphere placing us into an El Niño Advisory with about a 55 percent chance of weak El Niño conditions continuing through the spring (Figure 6). El Niños generally result in wetter-than-normal and cooler-than-normal conditions for Texas and act as a tropical storm suppressor. Given that this El Niño is weak and that we’re almost out of winter, it’s unlikely that this El Niño will have much affect on the state.

Figure 6. Forecasts of sea surface temperature anomalies for the Niño 3.4 Region as of January 19, 2019 (modified from source).

Figure 6: Forecasts of sea surface temperature anomalies for the Niño 3.4 Region as of January 19, 2019 (modified from source).

The U.S. Seasonal Drought Outlook through April 30, 2019, suggests drought improvements in southern Colorado, something that would be welcome for Elephant Butte Reservoir, and drought removal for Texas (Figure 7).

Figure 7: The U.S. Seasonal Drought Outlook for January 17, 2019, through April 30, 2019 (source).

Figure 7: The U.S. Seasonal Drought Outlook for January 17, 2019, through April 30, 2019 (source).



Author

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Robert Mace,
Deputy Executive Director & Chief Water Policy Officer at The Meadows Center for Water and the Environment

Robert Mace is  a Professor of Practice in the Department of Geography at Texas State University. Robert has over 30 years of experience in hydrology, hydrogeology, stakeholder processes, and water policy, mostly in Texas. 

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