December 8, 2020 National Drought Summary

The discussion in the Looking Ahead section is simply a description of what the official national guidance from the National Weather Service (NWS) National Centers for Environmental Prediction is depicting for current areas of dryness and drought. The NWS forecast products utilizedinclude the HPC 5-day QPF and 5-day Mean Temperature progs, the 6-10 Day Outlooks of Temperature and Precipitation Probability, and the 8-14Day Outlooks of Temperature and Precipitation Probability, valid as of late Wednesday afternoon of the USDM release week. The NWS forecast webpage used for this section is: http://www.cpc.ncep.noaa.gov/products/forecasts/.

Weather Summary: This U.S. Drought Monitor week saw intensification of drought across parts of the western U.S. including California, Nevada, and Colorado where precipitation has been below normal since the beginning of the Water Year (Oct 1). In California, statewide snow water content (SWE) is currently at 36% of the historical average for the date (Dec 7) and Water-Year-to-Date (WYTD) precipitation (statewide) is ranging from the bottom 10% to the bottom 33% with some areas in the Mojave Desert experiencing the driest on record for the period. According to NOAA’s National Centers for Environmental Information (NCEI), the 6-month period from June to November 2020 was the hottest and driest on record for both Arizona and California. Current snowpack conditions across the West are generally reflective of a La Niña-like precipitation pattern with the mountain ranges in the Pacific Northwest and some areas of the northern Rockies observing near-normal to above-normal snowpack conditions. Further south in the Four Corners states, basin-wide (6-digit HUC) SWE is below normal in nearly all drainage basins in the region. Elsewhere on this week’s map, areas of Texas including the Panhandle and central Texas saw some minor deterioration in conditions where both long and short-term precipitation deficits exist. In the Northern Plains, unseasonably warm temperatures and dry conditions continued this week leading to intensification of drought conditions in North Dakota where statewide precipitation for the September-November 2020 period ranked 3rd driest on record, according to NOAA NCEI. In New England, drought-related conditions significantly improved in response to heavy rains and snow associated with a Nor’easter that impacted the region during the weekend. The storm delivered heavy rains and strong winds to coastal areas as well as heavy snowfall in the mountains of New Hampshire and northern Maine.