According to the November 28, 2023 U.S. Drought Monitor, moderate to exceptional drought covers 30.3% of the United States including Puerto Rico, a decrease from last week’s 31.4%. The worst drought categories (extreme to exceptional drought) decreased from 7.3% last week to 6.5%.
The atmospheric circulation over the contiguous U.S. during this U.S. Drought Monitor week (November 22–28) behaved like a roller coaster.
The week began with a high-pressure ridge over the western U.S. and a low-pressure trough over the Mississippi Valley. Everything moved eastward in the jet stream flow, with a new trough pushing into the West at mid-week and a ridge building in the East. The week ended with the trough moving over the East and a ridge rebuilding in the West.
At the surface, cold fronts and surface low-pressure systems accompanied the upper-level troughs. The fronts and low-pressure systems spread above-normal precipitation across the Eastern Seaboard and in parts of the central Plains to the Great Basin, and brought cooler-than-normal temperatures to most of the contiguous U.S. When averaged over the week, the upper-level circulation pattern consisted of a ridge in the West and a trough in the East. This pattern generally inhibited precipitation in the West and directed dry air masses into the central part of the contiguous U.S., resulting in below-normal precipitation for much of the West, northern and southern Plains, and Mississippi to Ohio Valleys.
Beneficial rain during both this week and previous weeks resulted in drought contracting or being reduced in intensity from the southern Plains to the Southeast and in parts of Montana and the Mid-Atlantic States. Continued dry conditions this week expanded or intensified drought or abnormal dryness in parts of the northern Rockies, central Rockies to central High Plains, and Mid-Mississippi to the Ohio Valleys.
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 160 million people across the United States including Puerto Rico—about 51.6% 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.
