U.S. Drought Monitor Update for March 30, 2021

According to the March 30, 2021, U.S. Drought Monitor, moderate to exceptional drought covers 36.7% of the United States including Puerto Rico, a slight increase from last week’s 36.4%. The worst drought categories (extreme to exceptional drought) increased from 15.1% last week to 15.6%. 

The upper-level circulation pattern was a continuation of the pattern that has existed for much of the winter. Several Pacific weather systems moved through the jet stream flow across the contiguous United States. They tended to move southward and weaken over the West, and then were re-energized over the Plains and moved northeastward. This resulted in a long-wave trough in the upper levels over the West and a ridge over the East. The associated weekly temperature pattern was colder than normal in the West and warmer than normal east of the Rockies. 

The weather systems generally dried out as they crossed the West, although they gave parts of the Four Corners states some precipitation. The systems picked up Gulf of Mexico moisture as they moved east, spreading above-normal precipitation over much of the Deep South as well as the Upper Midwest and parts of the Northeast. The beneficial precipitation contracted drought and abnormal dryness in parts of the South and Midwest, while drought or abnormal dryness expanded or intensified across parts of the Northwest, northern Plains, and Northeast.  

Drought expansion was more than contraction, so the overall U.S. drought footprint increased a little this week.

Abnormal dryness and drought are currently affecting over 148  million people across the United States including Puerto Rico—about 47.8% of the population.