knowledge

knowledge

Tropical Storm Warnings are in effect for more than 42 million Americans in Southern California, with Hilary expected to be the first tropical storm to hit the region since Nora in 1997.

Hurricane Hilary has entered cooler water and is starting to weaken. The storm has been downgraded to a category 3 hurricane with sustained winds reaching 125 mph as it moves north-northwest at 16 mph.

Hilary is located more than 200 miles southwest of Cabo San Lucas – a sustained wind of 44 mph and a gust to 63 mph were recently reported at the Cabo San Lucas Marina.

The storm is moving slowly at 16 mph to the north-northwest.

The cyclone will continue to weaken as it continues into increasingly colder water and especially as it reaches land.

Rain will start to reach southern California and Arizona later Saturday and continue into Monday.

Flood Watches are in effect from Southern California and Arizona to Oregon and Idaho and tropical storm conditions are expected to begin in southern California on Sunday.

Tropical Storm force sustained winds up to 73 mph are possible near San Diego. Los Angeles could see sustained winds up to 57 mph.

Landfall is expected in Mexico on Sunday. The storm is then expected to be at tropical storm strength as it enters southern California.

In the unlikely event that Hilary makes landfall in California — instead of in Mexico, the most likely scenario — it will be the first landfalling tropical storm in California since 1939.

There is a major to extreme flood risk in Southern California. Heavy rainfall in association with Hilary is expected across the Southwestern United States, peaking on Sunday, and possibly lasting through Monday.

Rainfall amounts of 3 to 6 inches, with isolated amounts of 10 inches, are expected across portions of Southern California and southern Nevada. Dangerous to locally catastrophic flooding is likely. Elsewhere across portions of the Western United States, rainfall totals of 1 to 3 inches are expected, resulting in localized flash flooding. A tornado or two may occur Sunday over parts of the lower Colorado River Valley, Mojave Desert and Imperial Valley regions.

Climate change projections show California may see an increase in extreme rainfall from tropical cyclones by the end of this century. While climate change can decrease the overall number of tropical cyclones, it can increase the number of major (category 3-5) tropical cyclones.