In the West, the threat of flooding persists in the central and southern Rockies and portions of the Intermountain region. In contrast, hot, dry weather prevails in northern California and the Northwest, where winter wheat planting continues.

On the Plains, warm, dry weather prevails on either side of a front draped across central portions of the region. Significant rainfall is mostly confined to the central High Plains, where locally heavy showers are halting fieldwork and triggering flash flooding but providing some relief from long-term drought.

In the Corn Belt, markedly cooler weather prevails, following a brief period of beneficial showers. Freeze warnings are in effect early today in parts of northern Minnesota, well north of the corn and soybean areas.

In the South, widely scattered showers are associated with a cold front's passage. In advance of the front, hot weather continues to promote summer crop maturation and harvesting across the Deep South. However, soil moisture shortages remain a concern from the western Gulf Coast region to the Mississippi Delta.

Outlook: Canadian high pressure will bring sharply cooler air to the eastern U.S., although heat will linger across the Gulf Coast states. Meanwhile, copious monsoon moisture will continue to surge northeastward across the central and southern Rockies, generating additional heavy showers (2-4”, locally more) and flash flooding in parts of New Mexico and Colorado. Similar rainfall totals can also be expected on the central High Plains. This moisture will ultimately interact with a cold front pushing southeast out of central Canada, producing showers and thunderstorms across the Midwest before reaching New England by early next week. The remainder of the western U.S. will experience ongoing late-season heat, with daytime highs expected to average 10 to more than 15°F above normal in northern California and the Northwest. In southern Texas, there is a risk of potentially heavy rain contingent on the final track of developing Tropical Depression 10. The NWS 6- to 10-day outlook for September 18-22 calls for near- to above-normal temperatures and rainfall across the majority of the nation. Cooler-thannormal conditions will be limited to Pacific Northwest, while drier-than-normal weather will be confined to the MidAtlantic and Northeast.