July 30, 2012: The nation's weather

Weather Underground Forecast for Monday, July 30, 2012.

Expect little change in weather activity on Monday as monsoonal moisture streams across the Southwest, high pressure ridging persists in the south-central U.S., frontal disturbances push through the Midwest, and a trough of low pressure with waves of energy linger over the East.

In the West, monsoonal moisture will spread across southwestern California and the Four Corners kicking up afternoon monsoonal showers and thunderstorms. Western Arizona and southwestern California will see the brunt of this activity with possible flooding and flash flooding.

Meanwhile, high pressure ridging in the south-central U.S. will maintain strong daytime heating in the Central and Southern Plains and the Lower and Mid-Mississippi Valleys. Expect various Heat Advisories and Excessive Heat Warnings to remain in effect as daytime highs reach from 100 to 110 degrees.

In the Midwest, frontal impulses will push from the Northern and Central Plains into the Great Lakes and Ohio Valley with areas of showers and thunderstorms. Clusters of organized thunderstorms in the Great Lakes may kick up hail and strong wind gusts.

Further east, a cold front will become nearly stationary with waves of low pressure as it extends through the Mid-Atlantic into the Southeast, while a trough of low pressure remains situated over the northeastern quadrant of the nation. Afternoon showers and thunderstorms will continue near and ahead of the front from parts of the Carolinas through northern Florida and along the Central Gulf Coast.

Elsewhere, high pressure ridging over the south-central U.S. supported day of hot daytime highs from 100 to 110 degrees in the Central and Southern Plains and the Lower to Mid-Mississippi Valleys. A variety of Heat Advisories, Excessive Heat Warnings, and Red Flag Warnings remained in effect for this region. Temperatures in the Lower 48 states Sunday have ranged from a morning low of 37 degrees at Meacham, Ore. to a high of 109 degrees at Okmulgee, Okla.