In the West, an impressive heat wave is underway, although cool conditions linger across the region’s northern tier. Excessive heat warnings are in effect for today across much of Nevada and southern portions of Arizona and California, with temperatures near 120°F expected in the hottest deserts.

On the Plains, intense heat continues to bake the southern half of the region, where today’s high temperatures will again generally range from 100 to 110°F. The heat favors winter wheat maturation and harvesting, but is stressing rangeland, pastures, and summer crops. Meanwhile on the northern Plains, warm, dry weather is promoting the development of late-planted summer crops.

In the Corn Belt, somewhat drier conditions are arriving, although scattered showers linger in a few areas. The last few days have been especially wet in eastern Iowa, northern Illinois, southeastern Minnesota, and southwestern Wisconsin, leading to widespread lowland flooding.

In the South, scattered showers and thunderstorms are causing minor fieldwork delays but maintaining generally favorable moisture levels for pastures and summer crops.

Outlook: Heat will continue to build across the West before peaking during the weekend and early next week. The Western heat will boost irrigation demands, as temperatures will approach 120°F in agricultural areas of the lower Colorado Valley and southern California, and could reach 130°F in the hottest deserts. In contrast, markedly cooler air will arrive in the Midwest and Northeast by Friday, and will expand to cover most areas east of the Rockies during the weekend. Meanwhile, most of the rain during the next few days will fall east of the Mississippi River, with 2- to 4-inch totals possible in the Atlantic Coast States. During the weekend, however, seasonal (monsoon) showers may begin to develop in the southern Rockies. The NWS 6- to 10-day outlook for July 2-6 calls for near to below-normal temperatures across the central and eastern U.S., except for above-normal temperatures in the Northeast. Warmer-than-normal weather will also prevail in much of the West. Meanwhile, near- to above-normal precipitation across the majority of the U.S. will contrast with drier-than-normal conditions from the Pacific Northwest into the upper Midwest.