Southwest Climate Outlook February 2018

Date issued

Precipitation & Temperature: January was warm and dry across the Southwest. Precipitation was average to below average in most of Arizona, and below average to much-below average in New Mexico (Fig. 1a). Temperatures were much-above average to record warmest in Arizona, and ranged from near average to much-above average in New Mexico (Fig. 1b). Looking to the water year (Oct. 1-present), much of Arizona and New Mexico have been recording below-normal precipitation (Fig. 2) and above-average temperatures (Fig. 3) for the period.

Snowpack & Water Supply: Snowpack and snow water equivalent (SWE) are below average across the Southwest (Fig. 4), with most stations in Arizona and New Mexico having recorded less than 25 percent of normal, until recent storms in mid-February boosted SWE in central Arizona. La Niña typically brings warmer and drier conditions to the Southwest in winter, so these patterns are not unexpected, but they do raise concerns about drought impacts on water resource management, reservoir storage levels, rangeland and agricultural conditions, and wildfire risk.

Drought: Drought-designated areas were further expanded and intensified in the Feb. 13 U.S. Drought Monitor, with both Arizona and New Mexico documenting increases in the extent and intensity of drought since January’s outlook. The predominant classification in both states was severe drought (D2), with moderate drought (D1) covering the remaining areas except for small pockets of extreme drought (D3) (Fig. 5). These designations reflect short-term precipitation deficits and warm temperatures at monthly and seasonal timescales, as well longer-term drought conditions that track the cumulative effect of extended periods of warmer- and drier-than-normal conditions. A winter storm is bringing substantial moisture to southern and central Arizona at the time of this writing, which will help moderate short-term conditions but do little to alleviate long-term drought and its impacts.

Wildfire: Warm and dry conditions this winter, in conjunction with above-normal fine fuel loading and continuity, have led to a relatively early start to fire season, thus we are initiating the seasonal fire risk outlooks sooner than in previous years. The National Significant Wildland Fire Potential Outlook for February and March identifies above-normal wildland fire risk for southeastern New Mexico and portions of the borderlands region in southwestern New Mexico and southeastern Arizona (Fig. 6). The extended outlook for April and May identifies above-normal wildland fire risk in nearly all of Arizona and New Mexico. Notably, two fires are already burning in southern Arizona, including the Altar fire and the Knob Hill fire.

ENSO & La Niña: Oceanic and atmospheric conditions continue to indicate an ongoing La Niña event of near-moderate strength. The event is starting to show signs of returning to ENSO-neutral, and most forecasts and outlooks indicate a gradual decay to ENSO-neutral this spring. In the Southwest, La Niña events tend to produce drier-than-average winters, and given the observed conditions this fall and winter, the La Niña influence continues to cause concern in the Southwest in terms of winter precipitation, drought, and water resource management.

Precipitation & Temperature Forecast: The three-month outlook for March through May calls for increased chances of below-average precipitation (Fig. 7, top) and increased chances of above-average temperatures (Fig. 7, bottom) for the southwestern United States.

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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