According to the US-based National Hurricane Center, Tropical Storm Rosa was located approximately 225 km (140 mi) west-southwest of Punta Eugenia (Baja California Sur state) as of 02:00 (local time) on Monday, October 1. According to the latest forecasts, Rosa is expected to make landfall in the northern half of the Baja California peninsula on the afternoon or evening of Monday, October 1, before weakening into a tropical depression. A tropical storm warning is in effect for the western coast of the peninsula from Punta Abreojos (Baja California Sur) to Cabo San Quintin (Baja California). A lower tropical storm watch is in effect for the eastern coast of the peninsula from Bahia de los Angeles to San Felipe.
The storm is expected to bring 8-15 cm (3-6 in) of rain to Baja California and Sonora - and possibly up to 25 cm (10 in) in isolated areas - and up to 10 cm (4 in) across southern and central Arizona through Wednesday. This rain could provoke life-threatening flash flooding and debris flows across the region. The US National Weather Service (SNW) has issued flash flood warnings for Arizona as well as parts of California, Nevada, and Utah. Associated transportation disruptions and power outages are possible.
The Pacific Hurricane Season extends from May 15 to November 30 (and the Atlantic Hurricane Season from June 1 to November 30), with the largest concentration of storms typically occurring between August and October.
Individuals in the affected areas are advised to monitor local weather reports, anticipate flooding and transportation disruptions, avoid low-lying areas, including washes, riverbeds, and canyons, and adhere to instructions issued by local authorities. Remember that flash flooding and debris flows can occur at large distances from rainfall and that walking or driving through running water can be dangerous - 15 cm (6 in) of running water is enough to knock over an adult.