In the West, an active monsoon circulation continues to result in scattered showers and thunderstorms in the Four Corners States. Cooler air is starting to overspread the Pacific Northwest, but hot, dry conditions are maintaining the threat of additional wildfire activity from northern California to the northern Rockies.

On the Plains, isolated showers dot areas from Nebraska southward. Meanwhile on the northern Plains, hot, dry weather is promoting late-season small grain harvesting but is causing further deterioration of pastures and rangelands.

In the Corn Belt, a few showers are spreading across the upper Midwest in conjunction with a cold front. Across the remainder of the Midwest, hot, dry weather is causing renewed stress on pastures and immature summer crops.

In the South, scattered showers in the southern Atlantic region continue to slow fieldwork but are maintaining generally favorable conditions for pastures and immature summer crops. Very warm, dry weather covers the remainder of the region, and more rain is still badly needed across the Mid-South (e.g. Arkansas).

Outlook: During the next few days, the interaction between the Southwestern monsoon circulation and a pair of cold fronts will generate substantial rainfall (locally 2 to 4 inches) from the central and southern Plains into the middle Mississippi Valley. However, only light rain can be expected across the remainder of the Plains and the Midwest. Elsewhere, mostly dry weather will prevail in California and the Northwest, while much of the nation will continue to experience near- to above-normal temperatures. By early next week, Tropical Storm or Hurricane Isaac will be in the vicinity of Florida, posing a possible threat to the southeastern U.S. due to high winds, flooding rainfall, and a storm surge. The NWS 6- to 10-day outlook for August 28 – September 1 calls for near- to abovenormal temperatures nationwide, except for cooler-than-normal conditions in the Northwest. Meanwhile, below-normal rainfall across much of the western two-thirds of the U.S. will contrast with wetter-than-normal weather in the East.