September starts off with heat building along the West Coast, and cooler-than-average temperatures lingering across the eastern two-thirds. Showers and storms dot the Plains and southern tier. These details, along with our daily tropical outlook, are published every weekday at 5 a.m. ET.

The WeatherRadar shows storms forming along a stationary front draped across the south and along a system tracking from the Plains into the upper Mississippi River Valley.

Some isolated flash flooding will be possible in cities like El Paso, Texas, New Orleans, Mobile, Ala., and Tallahassee, Fla. Stay alert, especially if you plan to travel along I-10.

Cooler-than-average temperatures continue today across much of the country, with a few exceptions. Warmer-than-average highs are expected in the Pacific Northwest and across much of the West Coast.

The TemperatureRadar shows highs in the 100s across the Southwest, including in Phoenix, while Boise, Idaho, sees the mid-90s. A taste of autumn lingers across the eastern two-thirds, with cooler-than-average highs sticking around in cities like Atlanta, Houston and New York.

A tropical wave emerging off the coast of Africa may see some development in the coming days. We'll keep a close eye on the Atlantic Basin.

The Atlantic Hurricane Season peaks in September, and you will want to be ready. Learn more about how our hurricane alerts work here.