As Tropical Storm Hilary made landfall in Baja California, the National Weather Service warned that strong to severe thunderstorms are possible Sunday across southwestern Utah, bringing gusty winds and heavy rain.
The major hurricane was downgraded to a tropical storm Sunday morning but catastrophic conditions were still expected along the Baja California coast and in California on Sunday, when it made landfall before it is expected to continue north, forecasts show.
Parts of west-central Utah including western Millard and Juab counties are under flood watch until Sunday evening, according to the weather service, while southwestern Utah is under flood watch until Monday evening.
The weather service said excessive runoff could result in the flooding of rivers, creeks and other low-lying locations. Slot canyons, normally dry washes and areas near recent burn scars are also at risk.
Those with outdoor plans should monitor the weather and consider changing them, the weather service said.
Flash flooding is a relatively typical risk during monsoon season in Utah, but Tropical Storm Hilary will carry an elevated threat through Monday morning.
On Sunday, flash flooding is “possible” in Arches, Bryce Canyon, Canyonlands and Capitol Reef national parks, as well as Glen Canyon National Recreation Area, Grand Staircase-Escalanate National Monument, Natural Bridges National Monument, Grand Gulch and San Rafael Swell, according to the weather service. Flash flooding is “probable” in Zion National Park.
On Monday, flash flooding is “probable” in all five national parks, plus Glen Canyon National Recreation Area, Grand Staircase-Escalante National Monument and San Rafael Swell. Flash flooding is “possible” in Natural Bridges National Monument and Grand Gulch, according to the weather service.
Gusty winds are expected to develop over the southwest part of the state and then spread north and west Sunday night and into Monday, the weather service advised. South winds of 30 to 40 mph are expected, with some gusts up to 60 mph, and will decrease throughout the day Monday.
Southwest Utah and western Millard and Juab counties are also at risk for high winds, especially along Interstate 15 south of Cedar City and north of Blackrock Canyon, the weather service advised. A high wind warning is in effect from 11 p.m. Sunday to about 3 p.m. Monday.
Because of the wind risk, the weather service said travel on Interstate 80 and I-15 will be difficult for high-profile vehicles. Power outages also are possible, and people should secure outdoor objects like trampolines and garbage cans.
St. George is under a flood watch through Monday night, the weather service said, with heavy rain starting Sunday afternoon. Unpredictable weather is expected through at least Wednesday night. Scattered strong to severe storms are expected in southern Utah on Sunday afternoon and evening, with an isolated chance (2%) of tornadoes within 25 miles of St. George, according to the weather service.
In Salt Lake City, there is a slight chance of showers on Sunday and evening thunderstorms. Unpredictable weather is expected through at least Thursday, the weather service said.