The National Weather Service issued a flash flood watch Thursday for much of southern Utah, and flooding is “expected” or “probable” at the state’s national parks. The warning is in effect until 3 a.m. Friday.
Slow-moving storms that could produce heavy rainfall were expected late Thursday afternoon, continuing through early Friday. Those storms have yielded flash flood warnings — with the danger especially high in slot canyons, dry washes and small streams.
The NWS issued a flash flood warning through 9:45 p.m. for northeastern Garfield County in southern Utah. The warning stated that weather spotters reported flash flooding along the Escalante River in Escalante, and doppler radar estimates between 2 and 3 inches of rain have fallen. According to a tweet from the NWS, this storm “is capable of producing quarter-size hail and wind gusts to 60 mph as it moves to the northwest at around 10 mph.”
A flash flood warning was also issued for southeastern San Juan County until 9:30 p.m., with an expected rainfall rate of 0.8 to 1.3 inches in one hour. South central Kane County and south central Wayne County have also been issued flash flood warnings, which will be in effect until 10:45 p.m. and 9:45 p.m. respectively.
A flash flood watch was also issued for portions of east central Utah and southeast Utah, including Arches/Grand Flat, Canyonlands/Natural Bridges, the La Sal and Abajo mountains, from 4:12 p.m. until midnight. Capitol Reef National Park, Glen Canyon Recreation Area/Lake Powell and western Canyonlands are also under a flash flood watch through 3 a.m. Friday.
Flooding is expected Thursday evening in Canyonlands, Capitol Reef, Glen Canyon, Grand Staircase-Escalante, Natural Bridges and Grand Gulch. Flooding is “probable” — meaning some slot canyons, dry washes and small streams are expected to experience flash flooding — in Arches, Bryce Canyon, San Rafael Swell and Zion. On Friday, flash flooding is expected in Glen Canyon and Zion and “probable” in all of Utah’s other national parks and monuments.
According to the NWS, the moist air will remain over Utah through the weekend, with showers and thunderstorms expected during the afternoon and evening on Saturday and Sunday.
In Salt Lake City, temperatures will fall from highs in the low 90s on Friday to 87 on Saturday, 85 on Sunday and 82 on Monday. Afternoon and evening showers and thunderstorms are likely through the weekend — with an 70% chance on Friday and Saturday and an 80% chance for Sunday.
The forecast also calls for cooling temperatures in St. George, from a high of 99 on Thursday to 91 on Friday and Saturday and 89 on Sunday. Afternoon showers and thunderstorms are predicted in St. George, too — with a 60% chance on Friday, 50% on Saturday and 40% on Sunday.
— Tribune reporter Jordan Miller contributed to this story.
Follow @ScottDPierce