Seasonal Drought Outlook

 (through December)
Data Source(s): NOAA–Climate Prediction Center (CPC)

This summary is partially excerpted and edited from the December 13 Seasonal Drought Outlook technical discussion produced by the NOAA-Climate Prediction Center (CPC) and written by forecaster B. Pugh.

Since mid-November, a looping jet stream has carried moist air and cool temperatures into the Southwest, resulting in widespread snow across the higher elevations. As of December 15, the water contained in the snowpacks, or snow water equivalent (SWE), was more than 190 percent of average across the mountains of Arizona and north-central New Mexico. Despite the recent wet conditions, tools used to forecast precipitation favor below-median rain and snow on all time scales. La Niña heavily influences this outlook because the Southwest experiences below-average precipitation during most La Niña events. As a result, drought is forecasted to persist (Figure 11); there is moderate confidence in this outlook.

Elsewhere in the West, rain and mountain snow have brought near-average precipitation to Southern California since mid-November. Scant precipitation, however, fell in northern and central California and the northern Great Basin. Average SWE in the snowpacks in the Sierra Nevada was less than 25 percent of average as of December 1. Tools used to forecast precipitation suggest a tilt in the odds towards below-median precipitation across the southern half of California and southern Nevada. Drought development is expected in areas of California and Nevada by the end of March.

Notes: