Tropical Storm Hilary live updates: Hilary makes landfall in Baja California, Mexico

(LOS ANGELES) — Tropical storm warnings are in effect for more than 42 million Americans in Southern California, as Hilary is expected to be the first storm of its kind to hit the region since Nora in 1997.

Once a Category 4 hurricane, Hilary weakened as it approached the West Coast.

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

Flood watches are in effect from Southern California and Arizona to Oregon and Idaho.

Here’s how the news is developing. All times Eastern.

Aug 20, 5:29 PM EDT
All Southwest and Frontier airline flights suspended out of Ontario, California, airport

Ontario International Airport has suspended all Southwest Airlines and Frontier Airlines flights from Sunday at noon until Monday as Tropical Storm Hilary has begun to impact the West Coast, the airport said on social media.

Southwest Airlines has canceled 715 flights, the most flights of all U.S. airlines, according to FlightAware.

Frontier canceled 71 flights, according to FlightAware data.

Aug 20, 3:53 PM EDT
Latest maps show path of storm over the Southwest

The National Weather Service has issued a flash flood warning for parts of Southern California as the region begins to experience the effects of Tropical Storm Hilary.

Los Angeles County, including downtown Los Angeles, and Ventura County were included in the advisory.

Heavy rain is now becoming more widespread across portions of the region. The heaviest rain is focused over much of the Interstate 5 corridor, north of San Diego into Los Angeles.

Rainfall rates up to 1 inch per hour are possible in this area, and flash flooding will likely develop, forecasts show.

Rounds of heavy rain are expected to continue to sweep across the greater Los Angeles metro area through the next several hours.

Hilary will then move northward over the next 24 hours. As the system moves over land, it will weaken and become disorganized but could remain a tropical storm as it tracks across Southern California.

A tropical storm warning remains in effect for San Diego, Palm Springs, Riverside and Los Angeles.

Flood watches remain across a large swath of the Southwest, including cities like San Diego, Palm Springs, and Las Vegas. These watches have also been extended northward up to Idaho for the potential for heavy rain and flash flooding early in the week.

The National Oceanic and Atmospheric Administration’s Weather Prediction Center has issued a high risk alert for excessive rainfall across Southern, California, from Palm Springs to San Bernardino and up to Death Valley. “High Risk” days are rare and typically dangerous — 39% of all flood-related fatalities and 83% of all flood-related damages in the U.S. occur on “High Risk” days, records show.

A moderate risk alert for extreme rainfall is in effect from Las Vegas to San Diego and Los Angeles.

The biggest rainfall totals will be across the mountains east of San Diego, north and east of Los Angeles. Through Monday, a widespread 1 to 3 inches of rain is forecast across much of Southern California, the desert Southwest and across southern Nevada.

Three to 6 inches or more of rain is forecast across the mountains areas in Southern California. Several inches could still fall in some desert locations, with the greatest chance closer to Death Valley. Isolated amounts of 6 to 10 inches are still possible in some regions.

One to 2 inches of rainfall quickly falling in a desert location can cause major impacts due to the oversaturated soil.

-ABC News’ Daniel Peck

Aug 20, 2:18 PM EDT
Hilary makes landfall in Baja California, Mexico

Tropical Storm Hilary has made landfall just south of the U.S. border.

The storm system moved over the northern Baja California peninsula in Mexico at about 11 a.m. PT, the National Hurricane Center said in its latest advisory.

Hilary is currently located aout 215 miles south-southeast of San Diego and is moving north-northwest at 25 mph.

Maximum sustained winds have weakened to 65 mph.

The storm is expected to move through Southern California on Sunday afternoon, bringing catastrophic and life-threatening flooding over portions of the Southwest through Monday.

-ABC News’ Dan Peck

Aug 20, 1:11 PM EDT
Nearly 1,000 flights canceled ahead of storm

Airlines have canceled 944 flights so far as Tropical Storm Hilary approaches the West Coast, according to FlightAware.

The majority of the affected airports are in the West.

Southwest Airlines has cancelled 683 flights, the most flights of all U.S. airlines.

The airline has canceled all flights in and out of Palm Springs International Airport until at least Monday.

-ABC News’ Sam Sweeny

Aug 20, 11:29 AM EDT
Hilary weakens to a tropical storm

Hurricane Hilary, once a Category 4 hurricane, was downgraded to a tropical storm Sunday as it approaches the West Coast.

The center of the storm system is currently located about 220 miles south-southeast of San Diego. It is moving about 25 mph to the north-northwest.

About a quarter of an inch of rain has already fallen in Palm Springs on Sunday morning, while San Bernardino has seen about .8 of an inch, according to the National Weather Service.

Tropical storm force winds will start moving into Southern California over the next few hours.

Catastrophic and life-threatening flooding is likely over portions of the Southwest through Monday, forecasts show.

-ABC News’ Kenton Gewecke

Aug 19, 11:13 PM EDT
Hilary weakens to category 1 hurricane

Hilary continues to weaken as it moves north-northwest, now a category 1 hurricane with maximum sustained winds of 90 mph.

Aug 19, 10:53 PM EDT
Evacuation orders issued for areas of San Bernardino County

The San Bernardino County Sheriff’s Department issued a mandatory evacuation order for several regions at 7:15 p.m. PT. The regions include Oak Glen, Forest Falls, Mountain Home Village, Angelus Oaks, and northeast Yucaipa.

Earlier Saturday, San Bernardino County Sheriff’s issued an evacuation warning to its residents. At the time, San Bernardino County spokesperson David Wert told ABC News, “The purpose is to warn the population that there is an impending danger. They should start making arrangements to evacuate.”

The Sheriff’s office released an evacuation map to help residents know if they’re in the affected area.

Aug 19, 8:58 PM EDT
Gov. Newsom declares state of emergency ahead of Hurricane Hilary

California Governor Gavin Newsom declared a state of emergency for much of Southern California on Saturday ahead of Hurricane Hilary making landfall.

“California has thousands of people on the ground working hand-in-hand with federal and local personnel to support communities in Hurricane Hilary’s path with resources, equipment and expertise,” the governor said in a statement.

There are currently “more than 7,500 boots on the ground deployed” to help local communities the governor’s statement continued.

The impacts of the storm are expected to begin Saturday evening lasting through Monday, according to the statement.

Aug 19, 7:39 PM EDT
Biden briefed on Hurricane Hilary

President Joe Biden has received a briefing from senior staff on the latest preparedness plans for Hurricane Hilary and his team is working with state and local agencies ahead of the storm, according to the White House.

FEMA Administrator Deanne Criswell said earlier she has been providing “continuous updates” to the White House ahead of the storm.

-ABC News’ Justin Gomez

Aug 19, 6:22 PM EDT
LA County Parks to temporarily close

The County of Los Angeles Parks system said it will close on Sunday and Monday “out of an abundance of caution” due to Hilary.

That includes trails, lakes, beaches, pools, botanical gardens and playgrounds. All programs and classes are also canceled.

“While parks are not fenced in, visitors are encouraged to stay home,” LA County Parks said.

-ABC News’ Jennifer Watts and Alex Stone

Aug 19, 5:25 PM EDT
Hilary weakens to category 2 hurricane

Hilary continues to weaken as it moves north-northwest, now a category 2 hurricane with maximum sustained winds of 110 mph.

Aug 19, 5:25 PM EDT
FEMA in touch with California, Nevada governors

FEMA Administrator Deanne Criswell told reporters she is providing “continuous updates” to the White House about preparations ahead of the storm.

Criswell said she has also been in contact with California Gov. Gavin Newsom and Nevada Gov. Joe Lombardo to discuss “what type of support that they may need from FEMA and the federal family, but also to remind them that we are ready to support them as needed for this storm.”

Criswell said they will not be moving any resources from Maui to California or Nevada to respond to the storm.

“We are still fully engaged in our efforts to help the state and people of Hawaii recover but it’s also equally important that we are making sure communities that are in the path of Hilary also have the resources that they may need, and to what is likely going to be heavy impacts from rain and flooding,” she said.

-ABC News’ Justin Gomez

Aug 19, 4:49 PM EDT
Evacuation warning issued for areas of San Bernardino County

The San Bernardino County Sheriff’s office has issued an evacuation warning to residents in parts of the county.

“An evacuation warning is not an evacuation order — it’s a warning to people to be on notice they could be asked to evacuate at any moment,” San Bernardino County spokesperson David Wert told ABC News. “The purpose is to warn the population that there is an impending danger. They should start making arrangements to evacuate.”

The storm is expected to hit San Bernardino County “pretty hard,” Wert said, noting there is a threat of debris flowing into areas downstream of recent brushfires.

“Hopefully the order won’t come, but we want people to be ready,” Wert added.

-ABC News’ Samira Said

Aug 19, 4:06 PM EDT
Rare ‘high risk’ forecast for excessive rainfall issued

The National Oceanic and Atmospheric Administration’s Weather Prediction Center issued a rare “high risk” forecast for excessive rainfall for Sunday across a large swath of Southern California, from Palm Springs up toward Death Valley.

“High risk” forecasts are only issued a couple times a year on average, and 39% of all flood-related fatalities and 83% of all flood-related damages in the U.S. occur on those days.

A “moderate risk” for extreme rainfall has also been issued from Las Vegas to San Diego and Los Angeles. Numerous flash floods could unfold in these areas as well, with some of them potentially significant and very dangerous.

The deadliest hazard associated with tropical cyclones over the past decade is flooding from heavy rain.

-ABC News’ Dan Peck

Aug 19, 11:50 AM EDT
Southern California expected to see tropical storm winds Sunday

Winds from Hilary will reach tropical storm strength in Southern California on Sunday afternoon as the storm passes by.

Heavy rainfall is expected across the southwestern U.S., peaking late tonight through Sunday night. 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 catastrophic flooding is expected.

Elsewhere across portions of the western U.S., rainfall totals of 1 to 3 inches are expected, resulting in localized, some significant, flash flooding.

-ABC News’ Kenton Gewecke

Aug 19, 11:50 AM EDT
Hurricane Hilary downgraded to a category 3 storm

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

Landfall is expected in Mexico on Sunday. The storm is then expected to be at tropical storm strength as it enters southern California, marking the first tropical storm in Southern California since Nora in 1997, more than 25 years ago.

Catastrophic and life-threatening flooding is expected in Southern California.

Rain from Hilary should reach California later Saturday. Early morning monsoonal showers have lead to flash flooding Saturday morning, but that is not associated with Hilary.

-ABC News’ Kenton Gewecke

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