In the West, Tropical Storm Juliette has dissipated near the west coast of Mexico, but tropical moisture continues to generate locally heavy showers in the Southwest. In fact, the threat of flash flooding persists in parts of Arizona and southern portions of Nevada and California. Meanwhile, Northwestern small grain harvesting is advancing under a hot, dry weather regime. Among three dozen wildfires in California and the Northwest is the 200,000-acre Rim fire, only 32% contained and burning in and near Yosemite National Park.
On the Plains, hot, dry weather persists. Later today, readings above 100°F will be common across the central and southern Plains. The ongoing heat wave—along with mostly dry weather—is promoting fieldwork and crop development, but stressing immature, rain-fed crops in areas with limited soil moisture reserves.
In the Corn Belt, hot, dry weather is maintaining stress on filling summer crops. Today’s high temperatures will exceed 95°F in parts of the southwestern Corn Belt. Unfavorable dryness developed in parts of the western Corn Belt during the second half of June and in recent weeks has expanded to cover much of the Midwest.
In the South, very warm, mostly dry weather is generally favorable for fieldwork and crop development.
Outlook: The Midwestern heat wave will conclude during the Labor Day weekend as two cold fronts cross the region and a ridge of high pressure currently over the nation’s mid-section shifts toward the Intermountain West. Cooler air will arrive in the upper Midwest by Sunday, followed by cooling throughout the Corn Belt. During the first half of next week, heat will be concentrated across the northern High Plains and neighboring regions, although hot weather will begin to build back into the upper Midwest. Five-day rainfall totals could reach 1 to 2 inches in the Southwest and across the eastern one-third of the U.S., including the eastern Corn Belt. However, only light showers can be expected elsewhere, including the Plains and western Corn Belt. The NWS 6- to 10-day outlook for September 4-8 calls for above-normal temperatures across the Deep South and from the Pacific Coast to the Plains, while cooler-than-normal conditions will be limited to an area centered on the Ohio Valley, lower Great Lakes States, and central Appalachians. Meanwhile, near- to below-normal rainfall across the majority of the U.S. will contrast with wetter-than-normal weather from the Desert Southwest northward into Montana.