Drier-than-normal weather caused rapid development or expansion of drought from the central and southern Plains into the Mid-South and lower Midwest. In those areas, diminishing moisture reserves and above-normal temperatures set the stage for a crop disaster in some of the nation's most fertile land.
In contrast, beneficial showers eased or eradicated dry conditions across portions of the northern Plains, upper Midwest, and Atlantic Coast states. Some of the heaviest rain fell late in the month, when a series of cold fronts traversed the nation's northern tier and Tropical Storm Beryl soaked the southern Atlantic region. Another region that received much-needed May rainfall was the Rio Grande Valley and neighboring areas in New Mexico and Southern and Western Texas.
Meanwhile, a period of warm, dry weather in California and the Northwest followed a chilly start to spring. Cool, showery conditions returned, however, late in the month. Elsewhere, generally hot, dry weather in the Southwest brought an early end to the snow-melt season and fostered the spread of several wildfires.
In fact, near- to above-normal temperatures covered the nation, except for some slightly cooler-than-normal conditions from the Pacific Northwest to the northern High Plains. Monthly temperatures averaged at least 5°F above normal at several Southwestern locations and in a broad swath stretching from the central and southern Plains into the Midwestern and northern Mid-Atlantic states.
Weatherwise Contributing Editor BRAD RIPPEY is the U.S. Editor of the Weekly Weather and Crop Bulletin of the Joint Agriculture NOAA Weather Facility.
Weatherwise Contributing Editor JEFFREY B. HALVERSON is an associate professor of geography at the University of Maryland, Baltimore County.