Where is Hilary now? What Arizonans need to know about the post-tropical cyclone

Hilary has been downgraded to a post-tropical cyclone and has entered Southern California and Arizona.

The most severe effects are expected in Southern California, but the National Weather Service issued flash flood warnings for southwestern Arizona and wind advisories for much of the state.

Hilary swirled off the west coast of Baja California and clipped a peninsula near Bahia Tortugas, about 450 miles south of San Diego, sometime around 2 a.m. Arizona time. It was moving north-northwest at around 25 mph and hit landfall again on the Baja peninsula south of Ensenada. After that, the Category 1 hurricane weakened significantly and was downgraded.

The storm weakened significantly once it reached landfall but it will bring significant amounts of precipitation to certain areas of the Southwest — particularly in Southern California.

Hilary was the first tropical storm to hit Southern California in 84 years. In parts of the state, the storm dumped more than half the average annual rain.

The National Weather Service predicted, "catastrophic and life-threatening flooding likely over Baja California and portions of the southwestern U.S. through Monday."

In Arizona, the Weather Service issued several weather-related advisories and warnings.

The weather service said that Saturday through Sunday will see most of the impact for southwestern Arizona, describing the conditions as "deteriorating" for areas such as Yuma and La Paz counties. In both of these counties, two advisories are in place:

• Flood watch from Saturday 8 a.m. until Monday 5 p.m.

• Wind advisory Sunday between 11 a.m. and 11 p.m.

Hurricane Hilary updates: Sky Harbor sees 20 cancellations, 70 delays

Here's what Arizonans need to know as the hurricane brings monsoon activity into the state.

Where did Hurricane Hilary form?

Hilary formed as a tropical storm on Wednesday off Mexico's southern Pacific coast.

The National Hurricane Center elevated Hilary to a Category 4 hurricane on Friday morning and reduced it to Category 3 on Saturday morning. By Saturday afternoon, Hilary was reduced to Category 2.

What's the difference between a hurricane and a typhoon?

Hurricanes and typhoons are both tropical cyclones and are named based on where in the world they are occurring. If the cyclone is in the north Atlantic or the central or eastern parts of the north Pacific, then it’s a hurricane. If it’s in the northwest Pacific, it’s a typhoon.

If the storm occurs in the South Pacific or Indian oceans, then it’s generally referred to as just a tropical cyclone.

Therefore, Hilary's location makes it a hurricane.

That said, Hilary will very likely downgrade from hurricane status to a tropical storm once it reaches land, though the eastern part of the storm should reach parts of western Arizona such as Yuma with gusts up to 40 or 50 miles per hour.

Tracking Hurricane Hilary: Increased monsoon activity for Arizona

Is Hurricane Hilary going to hit Arizona?

Hurricane Hilary, a Category 2 storm moving northward from Mexico, is slated for landfall in Baja California on Sunday about noon. As of Saturday afternoon, it was still off the coast of Mexico.

While it will not directly hit Arizona, western Pima County and Yuma County are likely to see heavier precipitation and gustier winds throughout the weekend, according to the National Weather Service in Tucson.

In Yuma and western Pima County, gusty winds could reach up to 50 and 60 mph in some areas closer to California. These areas could also see up to half an inch of rain, or more or less depending on the location.

Thunderstorm activity is expected Saturday afternoon and evening, with respite overnight, and more thunderstorm activity on Sunday, but will be more “hit or miss” than Saturday, said Tom Dang, a meteorologist with the National Weather Service.

Tucson, Phoenix and northern Arizona will experience a typical monsoon day with standard showers and thunderstorms throughout the day, he said.

In Tucson and cities north of Tucson, there is a “potential for localized heavy rainfall and some gusty winds, but otherwise, it doesn't really feel like a hurricane,” Dang said.

However, residents living or traveling farther could see more serious impacts like localized flash flooding and strong winds that could be potentially damaging, he said.

He noted that Phoenix and northern Arizona will experience weather patterns similar to Tucson.

This hurricane is the first time in history the National Weather Service has released a tropical storm or hurricane advisory for southern California. In Arizona, while this weather event is not unprecedented, it is unusual.

What parts of Arizona will be impacted by Hilary?

While Hilary isn't expected to hit Arizona, it will impact southern parts of the state the most due to its proximity to Baja California, where it is expected to make landfall on Sunday.

According to the weather service, Yuma County up through La Paz County in Arizona and Riverside County in California will have the greatest risk of flash flooding. The Friday evening forecast indicated that rainfall could begin in the evening and continue into Saturday morning. It also noted that excessive rain could damage part of Interstate 10, which storms have done in the past.

The weather service also introduced a wind advisory for southwest Arizona and southeast California beginning Sunday afternoon through early morning Monday with projected wind speeds between 35 and 45 mph, which could potentially cause power outages from knocked-down power lines.

Hurricane Hilary in Arizona: How Yuma County and others are preparing for incoming monsoon weather

How much rain has Phoenix gotten this year? Will Hilary help?

Phoenix will receive some rainfall thanks to Hilary but will likely avoid any extreme storm conditions.

Matt Salerno, a meteorologist with the National Weather Service in Phoenix, said Phoenix has received 2.9 inches of rainfall for the year so far, which is roughly an inch and a half below normal due to an unusually dry monsoon.

Phoenix is forecast to receive a quarter to half an inch of rain, which will help make up some of the difference, though not enough to completely make up the difference.

Will Hurricane Hilary help Lake Mead, other reservoirs?

Hilary should also help bring more precipitation to Lake Mead and other reservoirs though likely not enough to offset the historic lows the former has.

Where else will Hurricane Hilary hit?

The National Hurricane Center expected Hilary’s impact would produce “catastrophic and life-threatening flooding likely over Baja California and the southwestern U.S. through Monday.”

Hilary is forecast to hit the Los Angeles metropolitan area before moving north toward Las Vegas and eventually into the Pacific Northwest before ultimately dissipating.

This article originally appeared on Arizona Republic: Where is Hilary now? What Arizonans need to know