According to the September 10, 2024 U.S. Drought Monitor (USDM), moderate to exceptional drought covers 28.8% of the United States including Puerto Rico, an increase from last week’s 25.2%. The worst drought categories (extreme to exceptional drought) increased slightly from 1.9% last week to 2.0%.
A strong ridge of high pressure anchored itself over the western contiguous U.S. (CONUS) during this USDM week (September 4–10) while a trough of low pressure held sway over the East. Hot and dry weather that was associated with the ridge dominated the Rockies to the West Coast and much of the northern Plains. Pacific weather systems moved across the U.S.–Canadian border, but they were dried out by the western ridge.
A dry northwesterly flow over central North America kept most of the CONUS east of the Rockies dry. A stationary front lay across the Gulf of Mexico coast throughout the period, while another cold front swept across the central and eastern CONUS beneath the upper-level trough. These fronts and the upper-level trough kept weekly temperatures cooler than normal across the eastern CONUS. The stationary front provided a trigger for tropical moisture along the Gulf of Mexico coast, which saw above-normal precipitation aided by Hurricane Francine near the end of the week. Other than the Gulf coast and parts of the Rockies (mainly Colorado) and eastern Great Lakes, which were wetter than normal, most of the CONUS had a drier-than-normal week.
Most of Alaska was warmer and drier than normal, Hawaii had a drier-than-normal week, and Puerto Rico and the U.S. Virgin Islands were mostly warmer than normal with a mixed precipitation anomaly pattern. The Gulf coast rains and summer monsoon contracted drought and abnormal dryness from Louisiana to the Four Corners states. But continued dry conditions, exacerbated by high evapotranspiration due to the heat in the West, resulted in expansion or intensification of drought and abnormal dryness in the central Plains to the Midwest, the Ohio Valley to the Southeast, and parts of the West. Continuing beneficial effects from last month’s rain resulted in contraction in Hawaii.
Nationally, expansion was much more than contraction, so the nationwide moderate to exceptional drought area percentage increased this week. Abnormal dryness and drought are currently affecting over 158 million people across the United States including Puerto Rico—about 50.9% 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 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. The U.S. Department of Agriculture’s World Agriculture Outlook Board also provides information about the drought’s influence on crops and livestock.
For additional drought information, follow #DroughtMonitor on Facebook and X.
