Southwest Climate Outlook November 2021

Date issued

Precipitation and Temperature: Oct precipitation was between below average and above average in Arizona and between average and much below average in New Mexico (Fig. 1a). Oct temperatures were between average and below average in Arizona and between average and much above average in New Mexico (Fig. 1b). Jan-Oct precipitation was between below average and much above average in Arizona and between much below and much above average in New Mexico (Fig. 2a). Jan-Oct temperatures were between above average and much above average across the Southwest (Fig. 2b). Precipitation totals for the past few months were wetter than average in northern California, western Nevada, much of Utah, and parts of central and southeastern Arizona, but dry across much of eastern Colorado and New Mexico (Fig. 3).

Drought: The U.S. Drought Monitor (USDM) showed minor improvements in drought categorizations in New Mexico and Arizona, but drought conditions are still found across both states, and the entire western United States (Fig. 4). The variable monsoon totals and the impending La Niña this winter, continue to raise concerns about long-term and cumulative precipitation deficits.

Snowpack & Water Supply: It is early in the season, but Nov 1 snow water equivalent (SWE) is highly variable in the Southwest, including well-above- and well-below-average conditions (Fig. 6). Most of the reservoirs in Arizona and New Mexico are at or below the values recorded at this time last year. Most are also below their long-term average (see reservoir storage for Arizona and New Mexico). Water levels at Lakes Mead and Powell continue to drive the conversation about Colorado River water management and shortage declarations in response to those water levels. The Rio Grande in New Mexico and Elephant Butte Reservoir raise similar concerns in New Mexico, although there has been less national attention compared to Lake Mead.

Hurricanes & Tropical Storms: The Eastern North Pacific saw activity across the bulk of the season, with 19 named storms but only two major hurricanes (Fig. 5). The accumulated cyclonic energy (ACE) was near normal through August, but September and October were quiet with only a few storms, resulting in a seasonal ACE of approximately 75% of normal.

ENSO Tracker: ENSO has reached La Niña status according to most outlooks, based on observed and forecast SSTs, emergent atmospheric conditions, and coupling between the two that is indicative of La Niña (see ENSO-tracker for details).

Published by the Climate Assessment for the Southwest (CLIMAS), with support from University of Arizona Cooperative Extension, the Arizona State Climate Office, and the New Mexico State Climate office.

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