In the West, rain and snow showers are returning to northern areas in conjunction with a slow-moving storm. Meanwhile, cool but dry weather is promoting fieldwork from California into the Southwest.

On the Plains, frost advisories are in effect this morning in parts of Kansas, Nebraska, and eastern Colorado. Through 7 am CDT, selected minimum temperatures this morning included 30°F at North Platte, Nebraska; Goodland, Kansas; and Lamar, Colorado.

In the Corn Belt, clouds and showers linger in the Ohio Valley and the lower Great Lakes region. Elsewhere, cool but dry weather favors a limited return to fieldwork, following recent rainfall.

In the South, isolated showers dot interior portions of the region, including Kentucky, Tennessee, and northern Alabama. Early today, the Mississippi River crest is nearing Greenville, Mississippi, where the water level is more than 16 feet above flood stage. Water diversions from the Mississippi River are well underway in Louisiana, using the Bonnet Carré and Morganza Spillways.

Outlook: A slow-moving storm system centered over the interior Southeast will drift northeastward, reaching the northern Atlantic Coast by week’s end. Additional rainfall associated with the storm could exceed 4 inches in the northern Mid-Atlantic region. Meanwhile, Northwestern storminess will edge eastward, arriving on the northern and central Plains during the mid- to late-week period. Rainfall totals of 2 to 3 inches may occur from Montana to Kansas. Elsewhere, dry weather will prevail for much of the week across the western Corn Belt, the lower Southeast, and the southern High Plains. Cool weather nationwide will be replaced by a late-week warming trend across the eastern half of the U.S. The NWS 6- to 10-day outlook for May 21-25 calls for cooler-than-normal weather from the High Plains westward, while near- to above-normal temperatures will prevail across the eastern half of the nation. Meanwhile, near- to above-normal precipitation across the majority of the U.S. will contrast with drier-than-normal conditions in the Southwest and Pacific Northwest.