According to the National Drought Monitor, 43.13% of the contiguous U.S. is free of drought, which is up from 39.06% last week. Heavy rain in the Northern Plains and upper Midwest led to the easing or eradication of drought in areas, but it also led to flooding. "By late May, minor to moderate flooding was underway at nearly 100 river gauges in the western Corn Belt, with major flooding occurring in a few locations," the Drought Monitor details. Rain was also seen on the southeastern Plains and in New England, but "little or no precipitation fell from California to the central and southern High Plains, further sharpening the gradient between drought and non-drought areas across the nation’s mid-section," the Monitor continues.
Major reductions in the coverage of dryness and drought occurred again in the Upper Midwest, with the 89.83% of the region now listed as drought-free, compared to 80.68% last week and 28.14% at the start of the year. "In Minnesota, Rochester’s record-setting precipitation totals for May and March to May reached 9.52 and 19.16 inches, respectively. Rochester’s previous records had been 8.41 inches in May 1982 and 15.87 inches in the spring of 2001," the Monitor elaborates. River flooding developed not only in the western Corn Belt, but also in parts of northern North Dakota. "During the latest drought-monitoring period, the axis of heaviest precipitation (locally 4 inches or more) cut across southeastern South Dakota and northwestern Iowa, where some locations experienced two-category reductions from severe drought (D2) to lingering subsoil moisture shortages (D0)," the Drought Monitor explains.
On the Plains, the divide between improving and worsening drought conditions continues to sharpen, with major improvement being seen across the northern half of the region. "In South Dakota, the portion of rangeland and pastures rated good to excellent rose to 30% on May 26, up 16 percentage point from a week ago. Similarly, South Dakota’s rangeland and pastures rated very poor fell from 51% to 29% during the week ending May 26. Both of the change numbers (+16 and -22 percentage points, respectively) led the nation," according to the Monitor.
Farther south, however, exceptional drought (D4) persisted on the central and southern High Plains. "Rain came too late for winter wheat in South Dakota (64% very poor to poor on May 26) and Nebraska (52%), and the maturing crop continued to suffer in parts of Texas (76%), Oklahoma (54%), Colorado (49%), and Kansas (45%)," the Monitor details. It continues, "From late March to early May, several freezes further damaged an already drought-stressed wheat crop on the southern High Plains." As the drought-monitoring period progressed, local downpours developed in Texas.
In its outlook for May 30 to June 3, the monitor says an active weather pattern will cover the nation’s mid-section. A slow-moving storm is expected to drift northward into the Dakotas on May 30, then slide eastward into the Great Lakes region by June 1. "Along the storm’s trailing cold front, a multiday severe weather outbreak can be expected across portions of the Plains, Midwest and Mid-South. The cold front should reach the Atlantic Seaboard in early June," the Monitor details. Additional rainfall amounts over the next five days could reach 1 to 3 inches on the Northern Plains and 2 to 6 inches from the east-central Plains into the lower Great Lakes region, including the middle Mississippi Valley. In contrast, the Monitor says mostly dry weather will prevail from California into the Southwest and along the southern Atlantic Coast, except for heavy showers in southern Florida. "Hot weather will prevail in advance of the storm, especially across the nation’s northeastern quadrant, while cool conditions will trail the system into the Plains and upper Midwest. By early June, hot weather will develop in the Pacific Coast States," the Monitor explains.