In the West, late-season snow showers stretch from the Sierra Nevada into the Intermountain region. Cool weather continues to slow crop development, especially in California and the Northwest.

On the Plains, cool, dry weather prevails in most areas. However, showers are developing on the northern High Plains, while mild, breezy conditions are increasing the wildfire threat on the southern High Plains.

In the Corn Belt, scattered frost was noted this morning in the upper Midwest. Frost advisories are in effect this morning across much of Wisconsin and parts of central Minnesota, eastern Iowa, and northern Illinois. However, dry weather in the western Corn Belt favors fieldwork. Meanwhile, cool, showery weather continues to delay corn planting and other activities in the eastern Corn Belt.

In the South, cool, dry weather prevails, except for showers in the southern Mid-Atlantic region and eastern sections of Kentucky and Tennessee. Early today, the Mississippi River crest is near Greenville, Mississippi, where the water level remains more than 16 feet above flood stage. Water diversions from the Mississippi River continue in Louisiana, using the Bonnet Carré and Morganza Spillways.

Outlook: Slow-moving storms will continue to affect the eastern and western U.S., respectively. Five-day rainfall totals could reach 3 to 5 inches in the  northern Mid-Atlantic States and southern New England. During the second half of the week, rain (locally 2 to 4 inches) will return to the northern half of the Plains and eventually overspread the western Corn Belt. Showers and locally severe thunderstorms will affect the southern half of the Plains. Late in the week, the eastern half of the U.S. will begin to experience a gradual warming trend. The NWS 6- to 10-day outlook for May 22-26 calls for above-normal temperatures across the eastern half of the U.S., while cooler-than-normal weather will be confined to parts of the West. Meanwhile, near- to above-normal precipitation across the majority of the nation will contrast with drier-than-normal conditions along the Pacific Coast and across the nation’s southern tier.