Southwest Climate Outlook May 2020 - Climate Summary

May 14, 2020
Ben McMahan

Monthly Precipitation and Temperature: April precipitation ranged between below average and above average in most of Arizona and between much below average and average in most of New Mexico (Fig. 1a). April temperatures were above average in most of Arizona and much of New Mexico (Fig. 1b). The daily average temperature anomalies for Apr 1 – May 20 (Fig. 2) highlight the fluctuations at select stations around the region.

Figure 1

Seasonal Precipitation and Temperature: Jan-Apr precipitation ranged between below average and muchabove average in much of Arizona and New Mexico, with large areas of below-average conditions in northern California, central Nevada, and southern Colorado (Fig. 3a). Jan-Apr temperatures were above average to much above average across most of the western U.S. (Fig. 3b).

Streamflow, & Water Supply: As of May 1, streamflow forecasts were below median in New Mexico, northeastern Arizona, southern Colorado, and eastern Utah, and above median in northwestern Arizona and western Utah (Fig 4). Many of the reservoirs in the region are at or above the values recorded at this time last year, but most are below their long-term average (see reservoir storage).

Drought: The May 5 U.S. Drought Monitor (USDM) maintains drought characterizations in the Four Corners region while expanding drought characterizations in Nevada, California, and southern Colorado (Fig. 5). “Moderate Drought” (D1) and “Severe Drought” (D2) characterizations are centered on the Four Corners region, with pockets of “Extreme Drought” now found in southern Colorado.

Wildfire: There are widespread areas of above normal wildfire risk in most of Arizona, western New Mexico, and southern parts of Colorado, Utah, and Nevada (Fig. 6).

ENSO Tracker: Conditions are back within the range of ENSO-neutral, and are expected to remain neutral through summer 2020, with increased chances for a La Niña event sometime this fall.

Precipitation and Temperature Forecast: The three-month outlook for June through Aug calls for slightly increased chances of below-normal precipitation in areas of eastern New Mexico, Texas, and northern Mexico, while parts of northwestern Arizona and southern Utah are showing slightly increased chances of above-normal precipitation (Fig. 7, top). The three-month temperature outlook calls for increased chances of above-normal temperatures across most of the western U.S. and northern Mexico (Fig. 7, bottom).

Online Resources

  • Figures 1, 3 - National Centers for Environmental Information - ncei.noaa.gov
  • Figure 2 - Climate Assessment for the Southwest - climas.arizona.edu
  • Figure 4 - Natural Resources Conservation Service - nrcs.usda.gov
  • Figure 5 - U.S. Drought Monitor - droughtmonitor.unl.edu
  • Figure 6 - National Interagency Fire Center - nifc.gov
  • Figure 7 - International Research Institute for Climate and Society - iri.columbia.edu