Producers in the Southwest will likely face warmer-than-average temperatures and less precipitation this winter due to the occurrence of La Niсa, at a time when reservoir levels are dangerously low.
The National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center released its La Niсa outlook for the first part of 2022, expecting warmer and drier conditions across the Southwest. NOAA expects drought to continue or worsen across much of the West, although the Pacific Northwest will see some relief.
La Niсa is responsible for much of early 2022’s temperature and climate outlooks, as the weather pattern increases the chances for cool and wet winters across the North and warm and dry conditions in the South. Typical La Niсa impacts are for the winter season averages, which include December to February, the Climate Prediction Center said in its outlook.
On shorter time scales, other influences come into play and weaken the weather pattern’s effect. Such was the case for January, when the phases of the Madden-Julian oscillation (MJO) and the Pacific-North American pattern were poised to undermine some of the typical La Niсa impacts at least through the first part of the month, according to the discussion from the NOAA Climate Prediction Center.
The MJO is a large area of storminess adjacent to a large area of clear, calm weather that makes its way around the tropics every two to three months, the center said. The weather pattern tends to disrupt the downstream mid-latitude weather in predictable ways. In December, the MJO was active in the western Pacific, which tends to favor cooler-than-average temperatures across most of the U.S.
The Pacific-North American pattern was expected to flip into its positive mode through at least the first half of January, which tends to oppose the typical climate impacts of La Niсa, such as cooler-than-average temperatures across much of the South.
This winter’s La Niсa is likely to be unfavorable for producers in the Southwest.
“This La Niсa probably means bad news for the American Southwest, which should see lower than normal rainfall this winter,” said Josh Willis, a climate scientist and oceanographer at NASA’s Jet Propulsion Laboratory. “This La Niсa may not be a whopper, but it’s still an unwelcome sign for an area already deep into a drought.”
Drought
Halfway through the summer of 2021, almost 100 percent of the western U.S. was in drought, the first time in 122 years of observation. A record-setting monsoon brought nearly a foot of rain to the Southwest last summer, which gave much reprieve to Arizona and New Mexico. As of early January, Arizona has 5 percent of the state in extreme drought, 21 percent in New Mexico, 17 percent in Texas and 40 percent in Oklahoma.
The Drought Monitor map as of Jan. 6 showed much of the Southwest in some stage of drought,
with northern Texas, western Oklahoma and northern New Mexico showing the most extreme signs of drought. Drought conditions in Oklahoma and northern Texas developed rapidly in September and worsened during a very warm and dry December. Central and western Texas, the Texas and Oklahoma Panhandles and central Oklahoma recorded 25 percent of normal precipitation or less over the past two months.
December total precipitation was less than half the long-term December average, according to the U.S. Drought Monitor, and temperatures in Oklahoma and Texas were more than 10 F above the average, making it the warmest of any winter month on record for both states.
Drought is expected to continue throughout the Southwest through the spring.
Reservoir levels
In 2021, Lake Powell and Lake Mead, the two largest reservoirs in the U.S., dropped to their lowest levels ever. As of Jan. 10, the Bureau of Reclamation reported Lake Powell was 27 percent full, and Lake Mead was 34 percent full. Lake Mohave and Lake Havasu were 88 percent and 89 percent full, respectively. Total lower Colorado River water supply system contents as of Jan. 9 were 37 percent full, 11 percent less than a year earlier.
The Colorado River Basin provides water to about 4-5 million acres of farmland in the Southwest. In August, the Bureau of Reclamation announced it would be cutting back water allocations to the Southwest in 2022.
Arizona will face the largest cutbacks, with about 18 percent of the state’s annual apportionment cut back and 8 percent of the state’s total water use for agriculture and human consumption cut back. Farmers who use water from the Central Arizona Project canal will see their water allocation drop by 30 percent. — Anna Miller, WLJ managing editor
