Forecast models suggest wet pattern likely to develop from tropical storm Ivo
A significant tropical disturbance appears to be setting its sights on much of the southwestern U.S. by early next week. Not unusual for late August, a tropical storm now south of Baja California should remain intact as it drifts northward over the next several days. In conjunction with this the upper air pattern is expected to remain 'troughy' along and off the U.S. west coast. This would maintain a southwesterly flow aloft which would encourage movement of tropical air into the Southwestern U.S. Tropical storm Ivo, is currently some 200 miles south-southwest of La Paz in southern Baja, is expected to continue drifting northward.
Current models suggest a showery pattern beginning across the desert southwest beginning Sunday morning and increasing in coverage and intensity into Monday. A deep moisture field may bring locally moderate amounts of rain across a broad area of southeastern California during the day Sunday, some local areas of heavy rain and gusty winds in thunderstorms into Sunday evening. By Monday morning, the heaviest area of rain should drift into northwest Arizona and may diminish slightly. A showery pattern is likely to persist over this area through mid-week.
If models verify with this system, it is probable the National Weather Service will issue flash flood/ flood watches/advisories/warnings likely beginning late Saturday or early Sunday. These storms could be of concern to desert travelers beginning Sunday in the region from about Palm Springs to El Centro, California (State routes 86 and 111), and in areas further east into Arizona, including Bullhead City and Kingman (Interstates 10 and 40).
For Los Angeles and vicinity, a 20% chance of showers beginning Sunday is forecast, with higher likelihoods in inland valley and mountain areas Sunday into Monday. Temperatures are expected to be seasonal, but increased humidity levels may cause increased discomfort.