The predicted track of Hurricane Rosa. (Image: Agencies)

MEXICO CITY (AP) — Hurricane Rosa was on a track Sunday to drench northwest Mexico and parts of the U.S. Southwest, prompting tropical storm warnings for the Baja California coast and flash-flood watches for parts of four U.S. states.

The U.S. National Hurricane Center says Rosa should still be at tropical storm force when it hits the Baja California Peninsula and Sonora state Monday with flooding rains. It's then expected to move quickly northwestward as it weakens, bringing 2 to 4 inches (5-10 centimeters) of rain to the Mogollon Rim of Arizona and 1 to 2 inches (2.5-5 centimeters) to the rest of the desert Southwest, Central Rockies and Great Basin. Some isolated areas might be more.

Rosa still had maximum sustained winds of 85 mph (140 kph) early Sunday and it was centered about 355 miles (570 kilometers) southwest of Punta Eugenia in Mexico. It was heading north at 12 mph (19 kph).

The National Weather Service announced flash flood watches through Tuesday for areas including southern Nevada, southeastern California, southwestern and central Utah and the western two-thirds of Arizona.

Forecasts call for heavy rainfall in the watch areas, which include Las Vegas, Phoenix and Salt Lake City, with possible flooding in slot canyons and normally dry washes and a potential for debris flows from recent wildfire burn scars.

Meanwhile, Tropical Storm Sergio was growing in the Pacific and could grow to near major-hurricane force within days, though it posed no immediate threat to land.

Sergio had winds of 50 mph (85 kph) early Sunday and it was centered about 485 miles (780 kilometers) south of Manzanillo, Mexico. The storm was moving west at 12 mph (19 kph).

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