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SALT LAKE CITY — A large portion of central and southeast Utah is under a flood watch Tuesday and Wednesday as monsoonal moisture returns to the state this week.
The National Weather Service's Salt Lake City and Grand Junction, Colorado offices issued a series of alerts ranging as far southwest as areas close to Zion National Park and north as areas near Strawberry Reservoir to large swaths of central and southeastern Utah. The flood watches go into effect at noon Tuesday and remain in place through Wednesday evening.
Threat of Flash Flooding is increasing as storms are already beginning to develop in Southern Utah. Storms will increase in coverage Tuesday, and become more widespread on Wednesday. Stay weather aware, and be sure to have a way to receive weather alerts as they are issued! #utwxpic.twitter.com/MhnArddd3J— NWS Salt Lake City (@NWSSaltLakeCity) September 20, 2022
Threat of Flash Flooding is increasing as storms are already beginning to develop in Southern Utah. Storms will increase in coverage Tuesday, and become more widespread on Wednesday. Stay weather aware, and be sure to have a way to receive weather alerts as they are issued! #utwxpic.twitter.com/MhnArddd3J
Excessive runoff may result in flooding of rivers, creeks, streams and other low-lying and flood-prone locations, including slot canyons, normally dry washes and slick rock areas," the alert states. "You should monitor later forecasts and be prepared to take action should flash flood warnings be issued."
This week's storms are being aided by a low-pressure front off the California coast, says KSL meteorologist Matt Johnson. The system has helped produce rainstorms into the Golden State the last few days, providing more than an inch or two in some locations, including over the large Mosquito Fire west of Lake Tahoe. But the system is powerful enough to also help pump moisture in Arizona up into Utah.
"By (Tuesday afternoon), it'll be bringing in showers and storms into southeastern Utah," Johnson said. "They hold onto showers and storms overnight and into (Wednesday)."
The system will then expand out to the rest of the state by Wednesday, providing a strong chance for showers and storms all over Utah. Some of these storms may linger into Thursday, as well, according to the current forecast. Johnson said one model is projecting up to one-third of an inch in parts of the Wasatch Front by Thursday, while other models project a possibility of up to a half-inch. Close to a half-inch of rain or more is forecast for parts of eastern Utah, too.
Most of the rain, however, is expected by the Four Corners area. More than an inch of rain is projected for areas in and around Blanding over the next few days.
In addition to the flood watches, the weather service advises anyone heading out into Utah's outdoors to be careful. Flash floods are possible at Bryce Canyon and Zion national parks, and "probable" at Utah's other national parks on Tuesday. The risk is elevated to at least probable on Wednesday with flash flooding "expected" at Arches and Canyonlands national parks, as well as Lake Powell, Grand Gulch and Natural Bridges National Monument.
There is an increased risk of flash flooding for southern Utah National Parks and recreation areas," the agency tweeted. "Make sure to check in with local visitor centers or ranger stations before heading out and have a plan if threatening weather approaches."
Full seven-day forecasts for areas across Utah can be found online at the KSL Weather Center.
This week's storms follow a very productive storm system last week that snapped record-breaking temperatures to start September. The storms brought nearly a half-inch of rain to Salt Lake City's official station at the city airport but over 2½ inches of rain to a station in the Wasatch Mountains northeast of Brigham City.
A station in the mountains near Zion National Park also received more than 2 inches. North Ogden (1.82 inches) and Millcreek's Olympus Cove station (1.71 inches) received the most of any of the state's valley communities. Those showers plus this week's forecast figures to boost Utah's final 2022 water year total before it ends at the end of the month.
The precipitation has helped Utah slowly chip away at the severity of its ongoing drought. The U.S. Drought Monitor lists nearly 57% of the state in at least extreme drought, down from a summer high of 84%.