U.S. Drought: Weekly Report for June 20, 2023

According to the June 20, 2023 U.S. Drought Monitor, moderate to exceptional drought covers 22.7% of the United States including Puerto Rico, an increase from last week’s 20.9%. The worst drought categories (extreme to exceptional drought) increased from 1.8% last week to 2.1%.

An unusual upper-level circulation pattern continued over North America during this U.S. Drought Monitor week (June 14-20). A strong upper-level ridge of high pressure stretched across North America, from Mexico to Hudson Bay and extending across the Great Plains. The ridge was responsible for the heat wave in Texas and above-normal temperatures in the northern Plains. High pressure also extended east from Mexico and across the Caribbean, bringing hot and dry weather to Puerto Rico and the U.S. Virgin Islands. Upper-level low pressure systems slammed into the ridge, dominating the weather in the western contiguous U.S. 

Another low-pressure trough dominated the weather in the Northeast, while a third upper-level low migrated southward and became cut off from the circulation to take up residence over the Southeast. These low-pressure systems spread rain over much of the Southeast and interior West, as well as parts of the Northeast where weekly precipitation was above normal; they also brought cooler-than-normal temperatures to these areas. 

Outbreaks of severe weather occurred along cold fronts from the southern Plains to the Southeast and the Midwest to Mid-Atlantic coast. But these systems worked against the power of the upper-level ridge, which inhibited precipitation in other areas, leaving much of the West coast, Arizona to the southern Plains, the northern Plains to Great Lakes, and the Mid-Atlantic coast drier than normal. 

Drought or abnormal dryness contracted or was reduced in intensity in areas that were wetter than normal, especially in parts of the Great Basin, western portions of the central and southern Plains, Southeast, and Ohio. But drought or abnormal dryness expanded or intensified where it continued to dry, especially across the northern Plains, Mississippi Valley, Great Lakes, and Mid-Atlantic coast, but also in parts of the Pacific Northwest, Texas, Puerto Rico, the Tennessee Valley, and Hawaii. 

Nationally, expansion exceeded contraction, with the nationwide moderate to exceptional drought area increasing this week. Abnormal dryness and drought are currently affecting over 177 million people across the United States including Puerto Rico—about 57.0% of the population.