Thunderstorms are expected to renew risks for isolated flash flooding throughout Utah, especially in slot canyons, on slopes scarred by recent wildfires and over slickrock areas in central and southern reaches of the state.

The National Weather Service on Tuesday predicted locally heavy rainfall will come with the lightning and thunderclaps, some of which will persist through the midweek along the Wasatch Plateau, Book Cliffs, the western Uinta Basin, the San Rafael Swell, Sanpete and Sevier valleys, and southwestern Utah.

Kane County, and the town of Kanab — already hit by some flash flooding Sunday night that briefly covered roads with water and mud and flooded several basements — will once more be on watch for floodwaters as storms pelt the nearby mountains.

Northern Utah will see some scattered thunderstorm activity, but little rainfall was expected heading into the midweek. Temperatures Wednesday and Thursday in the Salt Lake and Tooele valleys will reach the upper-90s — same as Tuesday — under partly cloudy skies.

Possibly heavier spurts of rain were coming for Utah's Dixie, but St. George still will top triple-digit temperatures. Wednesday will see 104 degrees, up 2 degrees from Tuesday's forecast; Thursday's readings should sizzle to 105, despite partially cloudy skies.

The Utah Division of Air Quality had some incrementally better news: after several days of "orange," or unhealthy conditions, the entire state was predicted to be in the "yellow," or moderate category for ozone and particulate pollution on Wednesday; that was a repeat of Tuesday's air quality forecast.

Intermountain Allergy & Asthma website rated mold as "high" and plantain as "moderate" on its pollen index as of Tuesday. Other allergens were "low," or did not register.

For more extensive forecast information visit the Tribune's weather page at http://www.sltrib.com/news/weather/.

remims@sltrib.com

Twitter: @remims