Major Hurricane Hilary reaches category 4 intensity

Hurricane Hillary quickly strengthened in a Category 4 hurricane Friday morning, and is poised to bring a host of life-threatening hazards to California and neighboring states beginning this weekend.

The panorama: Hilary’s peak winds intensified to 145 mph at 3 am ET. It is forecast to approach the Baja California peninsula on Saturday, bringing torrential rains to Southern California, Nevada and Arizona this weekend into early next week.

Threat level: A high-impact and dangerous flooding scenario is likely to unfold across the Southwest, with debris flows possible in burn-scarred areas and widespread flash flooding possible from large cities to mountains and desert areas.

• Computer models and National Weather Service forecasts show the potential for 2 to 10 inches of rain to fall in southern California, Nevada, Arizona and Utah, even in places where dry conditions currently exist.
• Some places in the desert Southwest could collect a year or more of typical rain in just two to three days. The San Diego and Los Angeles metropolitan areas are forecast to see heavy rain from this storm, with a peak on Sunday and Monday.
• There is considerable uncertainty about the precise track of the storm and whether the storm will reach the southwest as an intact tropical system. Even in a weakened state, high winds could cause damage throughout Southern California, particularly to tall buildings and higher elevations.

Status of the situation: At 3 a.m. ET, the center of the hurricane was located about 400 miles south of Cabo San Lucas, Mexico, and was moving west-northwest at 13 mph.

• Storm intensified at 75 mph in 24 hours, more than twice the speed that defines rapid intensification.

What they are saying: He National Hurricane Center warned Thursday that Hilary’s motion relative to the shape of the Baja California peninsula makes it “nearly impossible” to predict whether the storm’s center will move inland, causing its winds to die down before it reaches southwest of USA

• He The NWS office in San Diego warned Thursday night of “high potential” flash flooding from the storm.
• Nearly 26 million people in four states were placed on flash flood watches for the hurricane, by weather.gov.

Context: human caused climate change it is causing more frequent and intense precipitation extremes, and it is also causing wetter tropical storms and hurricanes.

• Also, you are doing rapid intensification of such storms more common and faster.
• It is extremely rare, but not unheard of, for a tropical storm or hurricane to make landfall in Southern California, because the region is protected by relatively cool ocean waters.

Retrospective scene: Just two tropical storms they have come within 100 miles of San Diego, according to meteorologist Kieran Bhatia.

• The last tropical storm to make landfall in southern California struck in 1939.

Zoom out: The general weather pattern that will accelerate Hilary to the southwest will feature a historically intense and extensive dome of heat over the central US, along with an area of ​​low pressure expected to move near the central California coast. .

• The heat dome, which the National Weather Service described on Wednesday as “abnormally strong/massive,” is likely to cause a prolonged heat wave across the central US, spreading to the south and southeast this weekend. week to next week.
• Anomalous weather patterns often bring Extreme weather events, and the heat dome will help deflect the jet stream northward across Canada as a jet stream trough forms near the west coast.
• Upper level winds blowing between these two weather systems will open a corridor that will allow the tropical weather system to speed its journey north and into southern California while directing a mighty atmospheric river to the southwest.

The bottom line: A damaging, potentially even disastrous, tropical storm-related event is increasingly likely to occur for southern California and other southwestern states beginning Saturday, but uncertainty remains about how intense the storm will be at that point and its precise trajectory.

• “The combination of heavy rain and strong winds could very well make this event high-impact in parts of Southern California,” NWS San Diego meteorologists wrote in a statement. forecast discussion.

Editor’s Note: This article has been updated with new details.