MEXICO CITY, MEXICO: Hurricane Hilary has been rapidly intensifying in the Pacific Ocean southwest of Mexico with forecasters warning that it could potentially bring “significant impacts” to parts of southwest US this weekend.

Hilary, the eighth named storm of the Eastern Pacific hurricane season this year, strengthened into a major Category 3 hurricane after sustaining winds of 120 mph and even stronger gusts on Thursday, August 17.

The storm is expected to grow into a Category 4 hurricane on Friday, with winds of at least 130 mph, according to the National Hurricane Center.

Hilary emerged 470 miles off the Mexican coast of Manzanillo on Wednesday and was moving west-northwest toward Baja California.

When will Hurricane Hilary hit the US?

Several regions of southwestern US might see Hilary's downpour as early as Saturday, with California expected to experience its harshest effects early on Monday, according to CNN.

"Rainfall impacts from Hilary within the Southwestern United States are expected to peak this weekend into Monday. Flash, urban, and arroyo flooding are possible with the potential for significant impacts,” the NHC noted in an advisory.

Forecasters also warned that shifts in the predicted path will also impact which parts of northern Mexico would experience the worst of Hilary’s winds, which are powerful enough to uproot trees, bring down power lines, and seriously harm property nearest to the storm's center.

Mudslides and flash flooding are possible from a general 3 to 6 inches of rain across Mexico’s Baja Peninsula from Thursday to early Monday.

What is the potential impact of Hurricane Hilary?

Hurricane Hilary is predicted to weaken considerably before it makes landfall in Southern California and certain regions of the southwest but there are growing chances that it will have a substantial impact there in the form of floods and heavy rain.

Southern California is expected to witness some of the heaviest rainfall brought by the hurricane. Locally higher amounts of up to 6 inches are possible in areas impacted by the heaviest deluges.

Several regions of Arizona, Central California, and northern Nevada could also receive rainfall amounts of 1 to 2 inches. Multiple days of heavy rainfall will give the ground little opportunity to absorb moisture and can progressively worsen the flood threat.

Daniel Swain, a climate scientist at the University of California at Los Angeles, said Wednesday that “multiple years’ worth of precipitation” could potentially fall in some of California’s driest areas.

Hilary is more likely to make landfall in Mexico before moving into California. However, if the storm does make landfall in California as a tropical storm, it will be the first to do so in over 84 years and just the third tropical storm or greater to do so in recorded history, according to data from the National Oceanic and Atmospheric Administration.