The nation’s weather

Weather Underground Forecast for Friday, July 22, 2016

Active weather will impact the northern Plains on Friday, while extreme heat affects the Southwest.

A cold frontal boundary will stretch southwestward from the upper Great Lakes to the central Plains. As this frontal boundary transitions eastward, it will produce showers and thunderstorms across New England, the northern Mid-Atlantic and the Midwest. Severe thunderstorms will be possible in New England and eastern New York. These thunderstorms will be capable of producing large hail, dangerous straight line winds and isolated tornadoes. Moisture from the Gulf of Mexico will also initiate showers and thunderstorms across the Deep South and parts of the Southeast.

Meanwhile, a wave of low pressure will take shape over the northern high Plains. This system will collide with anomalously warm temperatures, which will set the stage for heavy rain and strong thunderstorms. Severe thunderstorms will be possible in eastern Montana, northern South Dakota, North Dakota and western Minnesota. These thunderstorms may generate large hail, dangerous straight line winds and isolated tornadoes. Heavy rain could lead to flash flooding in North Dakota, northeast South Dakota and northwest Minnesota.

Additionally, showers and isolated thunderstorms will persist across the Four Corners and the eastern Great Basin due to monsoonal moisture and daytime heating. Temperatures are forecast to spike above 110 degrees across portions of the Desert Southwest. Excessive heat warnings and heat advisories are in effect for parts of southern California and Arizona.

Temperatures in the Lower 48 states Thursday have ranged from a morning low of 32 degrees at West Yellowstone, Mont. to a high of 111 degrees at Imperial, Calif.