Quarterly Climate Impacts and Outlook for the Western Region for September – November 2020.  Dated December 2020.

Temperatures were above-average during the fall west of the Rocky Mountains, favored by a strong high pressure ridge anchored along the coast. Although fall is typically dry in the southern half of the West, the persistent ridge prevented landfalling Pacific storms, leading to well-below normal precipitation in many regions.

Provides information on the typical La Niña winter pattern; the La Niña outlook; potential impacts; and comparisons of conditions during previous La Niña years.

NOAA’s Regional Climate Services Program created these outlooks to inform the public about climate impacts within their respective regions. Each regional report contains easy-to-understand language, and anyone can access them through the Drought Portal.

Conditions Favor El Niño this Winter: Significant drought expected to lessen in parts of the Southwest and persist in others.

From October 2017 to September 2018, the Southwestern U.S. experienced below-normal to record-low precipitation.
Long-term precipitation deficits and record-high temperatures have contributed to very low streamflows and reservoir levels.
Conditions favor the development of El Niño this winter, but significant drought is expected to persist in most of Utah and Colorado.

WATER YEAR (OCTOBER 2017-SEPTEMBER 2018)

Extreme Drought Entrenched in the Four Corners. Weak El Niño Expected through Winter and Spring.

• Extreme drought remains entrenched in the Four Corners area of the Southwest.
• Recent above-normal precipitation has resulted in some drought improvement in eastern areas of Colorado and New Mexico.

Quarterly Climate Impacts and Outlook for the Western Region for June – August 2020.  Dated September 2020.

Summer temperatures were well above normal in California, Nevada, the Four Corners and Wyoming. Pacific Northwest and Montana temperatures were near normal or above normal with a few small pockets below normal. Large areas of the West observed a drier than normal summer with southeast California into Arizona being the driest. This is the second year in a row with “missing” monsoon rains.

Quarterly Climate Impacts and Outlook for the Western Region for September – November 2019.  Dated December 2019.

Autumn temperatures were well below normal across the northern tier of the region while near to above normal temperatures were observed across California and the Southwest.  Several areas of the West reported below normal autumn precipitation including northern California, eastern Utah, and western Colorado. Montana, northern Wyoming, northwestern Utah, and the Southwest reported above normal precipitation.

Quarterly Climate Impacts and Outlook for the Western Region for June – August 2019.  Dated September 2019.

Quarterly Climate Impacts and Outlook for the Western Region for March – May 2019.  Dated June 2019.

Spring temperatures were variable across the West.  The North Pacific storm track remained active through the spring season bringing above normal precipitation to much of the West.

Background: The 2017-2018 Drought in the Southwest

According to the U.S. Drought Monitor’s drought severity designations, “Abnormally Dry” conditions crept into the Southwest region in October 2017 and deepened into widespread “Moderate Drought” in November 2017. The region was in “Severe Drought” by January 2018; “Extreme Drought” by March 2018; and “Exceptional Drought” by May 2018. The “Exceptional Drought” lingered in the region until January 2019. In 2018, the region experienced more than 45 weeks in drought.

Quarterly Climate Impacts and Outlook for the Western Region for December 2018 – February 2019.  Dated March 2019.

Persistent stormy conditions helped to maintain near-to-below normal temperatures across much of the West this winter.  Abundant precipitation and moderate temperatures helped alleviate drought conditions in large areas of the West.