Southwest Climate Outlook April 2020 - Climate Summary

April 30, 2020
Ben McMahan

Monthly Precipitation and Temperature: March precipitation ranged between average and record wettest in Arizona and between below average and record wettest in New Mexico (Fig. 1a). March temperatures were average to much above average in Arizona and above average to much above average in New Mexico (Fig. 1b). The daily average temperature anomalies for Mar 1 – Apr 14 (Fig. 2) highlight the fluctuations at select stations around the region.

Figure 1

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

Figure 3

Water Year Precipitation: Water year precipitation to date (since Oct 1, 2019) has been normal to much above normal for much of Arizona and New Mexico (Fig. 4), while southeastern New Mexico recorded record wettest conditions, and northern New Mexico was below normal.

Figure 4

Snowpack & Water Supply: As of Apr 13, snow water equivalent (SWE) was mostly below median in New Mexico, eastern Arizona, and southern Colorado, while southern Utah and northern Arizona were more consistently above median (Fig 5). 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).

Figure 5

Drought: The Apr 7 U.S. Drought Monitor (USDM) maintains drought characterizations similar to last month in the Four Corners region, while expanding drought in central and southeastern New Mexico (Fig. 6). “Moderate Drought” (D1) and “Severe Drought” (D2) characterizations are centered on the Four Corners region, reflecting localized acute and accumulated precipitation deficits.

ENSO Tracker: Oceanic and atmospheric conditions are generally consistent with an ENSO-neutral outlook for 2020, although some forecasts hint at a possible La Niña event later this year.

Precipitation and Temperature Forecast: The three-month outlook for May through July calls for slightly increased chances of below-normal precipitation in areas of western Arizona and northern Mexico. The outlook calls for slightly increased chances of above-normal precipitation in central New Mexico and much of Utah and Colorado (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 - West Wide Drought Tracker - wrcc.dri.edu/wwdt
  • Figure 5 - Natural Resources Conservation Service - nrcs.usda.gov
  • Figure 6 - U.S. Drought Monitor - droughtmonitor.unl.edu
  • Figure 7 - International Research Institute for Climate and Society - iri.columbia.edu