Growing concerns surround Hurricane Hilary’s trajectory as it heads for the southwestern US and parts of California, with predictions of substantial flooding rainfall in the coming days. This unusual occurrence has prompted the issuance of the first-ever tropical storm watch for California.

Meteorologists are warning that Hilary has the potential to unload more rain than the region typically receives in a year, spanning across California, Nevada, and Arizona. This heightened risk has led to a rare Level 4 out of 4 excessive rainfall warning for portions of California, marking the first time such a high risk has been declared for this area.

As of Friday morning, Hurricane Hilary, once a formidable Category 4 hurricane, was positioned approximately 400 miles south of Cabo San Lucas, Mexico, with sustained winds of 145 mph and even stronger gusts, according to the National Hurricane Center.

Remarkably, Hilary underwent rapid intensification within a 24-hour span, transitioning from a tropical storm to a Category 4 hurricane. Predictions suggest that it will maintain this Category 4 status as it approaches Mexico’s Baja California peninsula over the weekend.

The storm’s trajectory may briefly bring it to Category 5 strength before encountering cooler waters, which would likely weaken it.

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Given Hilary’s path, hurricane watches, tropical storm watches, and tropical storm warnings have been issued for Baja California and northwest Mexico. Meanwhile, the potential impact on the US remains uncertain, with small shifts in the hurricane’s path potentially altering the forecasted severity of rain and wind.

While the likelihood is that Hilary will primarily impact Mexico before reaching California, the possibility of a tropical storm landfall in California exists. If this occurs, it would mark the first instance of such an event in nearly 84 years, according to the National Oceanic and Atmospheric Administration’s records.

For the first time in history, a tropical storm watch was initiated for parts of Southern California, stretching from the California/Mexico border to the Orange County/Los Angeles County line.

As Hilary heads northward, experts expect its strength to wane upon reaching Southern California and the Southwest. Regardless, the storm is expected to intensify heavy rainfall and heighten the risk of flooding, with the most severe conditions anticipated on Sunday and Monday.

The gravity of the excessive rainfall risk is underscored by its rarity. These high-risk conditions are declared on fewer than 4% of days on average annually, yet account for a significant portion of flood-related damage and fatalities, as documented by the Weather Prediction Center.

Southern regions of California and Nevada could receive 3 to 5 inches of rain, with isolated areas seeing up to 10 inches. Additionally, central parts of these states, as well as parts of

western Arizona and southwest Utah, are predicted to experience 1 to 3 inches of rainfall.

Hilary’s influence could lead to an unprecedented volume of precipitation in some of California’s driest areas. Notably, Death Valley, which typically receives a mere 2 inches of rainfall per year, could receive up to 2 years’ worth of rain in a single day. Similarly, Las Vegas might see 2 to 4 inches of rainfall, greatly surpassing its annual average of 3.75 inches.

The extended period of rain could oversaturate the ground and overwhelm water systems, potentially exacerbating the flood threat.

In response to the impending conditions, flood watches have been issued for the weekend across southern California, encompassing regions from San Diego to Los Angeles. The National Weather Service in Los Angeles has also cautioned about the potential for high surf, rip currents, and coastal flooding.

While the East Pacific is experiencing a surge in tropical activity, the Atlantic is also gearing up for increased tropical action. Multiple areas of concern extend from the Cabo Verde Islands to the Gulf of Mexico, with the Gulf of Mexico specifically identified as a potential site for tropical development next week. Additionally, three other areas in the tropical Atlantic are being closely monitored for possible formation into tropical depressions or storms.

Source: CNN