The flash flood watch, which generally follows the Interstate 15 corridor, is in effect until Thursday evening.
By early Thursday afternoon, the rain had prompted an array of road closures and havoc. Crews shut down two sections of State Road 191 near Duchesne and Helper and were clearing State Roads 31 and 29 in Sanpete and Emery Counties, respectively.
In Zion National Park, the Zion-Mt. Carmel Highway also was shut down by park officials, but the park re-opened the road after close to 24 hours on Thursday afternoon. The park continued to urge caution against sand and construction vehicles still on the highway.
Pete Wilensky, NWS lead forecaster, said the rain is coming from a slow-moving storm out of Arizona. The rain produced high flows in the Price and Dirty Devil rivers Thursday morning and has raised the water level in Lake Powell several inches. Wilensky said the rain also was likely causing debris flows off the Seeley Fire burn scar in Huntington Canyon, though roads in the area were closed Thursday and authorities did not have updated information on the region.
Wilensky said the storm poses a greater threat to northern Utah on Thursday.
"The heavy rain threat will shift into the north today and will continue down south," he explained.
Authorities have urged Utahns to exercise extra caution near burn scars, where even small amounts of water can trigger debris flows. Flooding and slides are less likely in urban areas, though Wilensky added that there could be some street flooding Thursday.
Forecasters also issued a more-severe flood warning for the south-central region of the state. The affected area extends from Zion National Park in the south to just above Price in the north. It includes an area that saw significant flooding Tuesday night and Wednesday.
According to Wilensky, the rain should taper off entirely by next week and will be followed by drier conditions and possibly a weak cold front.
Despite the rain, Utahns should be able to breath easy Thursday; the Utah Division of Air Quality predicts "green" conditions across the state.
Forecasters predicted a high in Salt Lake City of 83 degrees Thursday and 79 degrees Friday; Provo 79 and 74 respectively; Ogden 81 and 73; Logan 79 and 75; St. George 77 and 89; Duchesne 71s; Moab 82 and 79; Park City 69 and 64; Wendover 74 and 72.