According to the December 5, 2023 U.S. Drought Monitor, moderate to exceptional drought covers 28.9% of the United States including Puerto Rico, a decrease from last week’s 30.3%. The worst drought categories (extreme to exceptional drought) decreased from 6.5% last week to 6.2%.
The atmospheric circulation over the contiguous U.S. during this U.S. Drought Monitor week (November 29–December 5) generally consisted of an upper-level ridge over the West and a trough over the East, but it was complicated and distorted by Pacific weather systems (short-wave troughs) moving in the jet-stream flow. The ridge tried to keep temperatures warmer than normal, while cold fronts associated with the Pacific troughs brought in colder-than-normal air. When averaged over the week, the temperature anomaly pattern across the contiguous U.S. was a mixture of warmer-than-normal areas and colder-than-normal areas. The ridge generally inhibited precipitation, while the cold fronts and their associated surface low pressure systems generated areas of heavy rain.
Precipitation for the week was above normal in several streaks that stretched from the Texas panhandle to eastern Great Lakes, across Arkansas, from northern Mississippi to eastern Tennessee, and across much of the Gulf of Mexico coast. Parts of the Southwest were wetter than normal, several atmospheric rivers brought above-normal precipitation to the Pacific Northwest, and a Kona Low gave much of Hawaii a wetter-than-normal week.
It was a drier-than-normal week across California to the Great Basin, across much of the Rockies to Great Plains, in the Upper Mississippi and Ohio Valleys, across the Florida peninsula, and from central Alabama to the Carolinas. A persistent high-pressure ridge kept Puerto Rico and the U.S. Virgin Islands warmer and drier than normal. Drought or abnormal dryness expanded or intensified in areas that have seen persistently dry conditions. But much of the precipitation this week fell in drought-stricken areas, so drought or abnormal dryness contracted or was reduced in intensity in the Pacific Northwest, from Kansas to Illinois, across Hawaii, and in parts of the Deep South.
Nationally, contraction was more than expansion, so the nationwide moderate to exceptional drought area decreased this week. Abnormal dryness and drought are currently affecting over 151 million people across the United States including Puerto Rico—about 48.8% of the population.
The full U.S. Drought Monitor weekly update is available from Drought.gov.
In addition to Drought.gov, you can find further information on the current drought as well as on this week’s Drought Monitor update at the National Drought Mitigation Center
The most recent U.S. Drought Outlook is available from NOAA’s Climate Prediction Center and the U.S. Department of Agriculture provides information about the drought’s influence on crops and livestock.
For additional drought information, follow #DroughtMonitor on Facebook and Twitter.
