Scattered showers and thunderstorms may foster additional flash flooding concerns throughout the overnight hours of October 22, according to the National Weather Service. The weather prediction center noted that these storms could affect southern Utah, central Utah, northern Arizona, and southwest Colorado.
The National Weather Service Weather Prediction Center in College Park, Maryland, reported that a strong upper trough and closed low over the Southwest U.S. is gradually advancing eastward. Satellite imagery indicates the energy is taking on a negative tilt. This enhanced forcing, combined with steepening mid-level lapse rates, is expected to favor scattered showers and thunderstorms through the overnight hours of October 22.
Radar imagery shows some of the stronger and more organized cells located over areas of far northern Arizona and into southern Utah. While arriving dry mid-level air may mitigate some rainfall rates, some storms may still produce rainfall rates as high as 1 to 1.5 inches per hour. Localized cell-training remains possible, which could yield storm totals of up to 2 inches.
The potential for flash flooding is highest in slot-canyon regions and burn scar locations. Additionally, normally dry washes may see potential for runoff concerns. MUCAPE values in the area are locally still over 500 J/kg, and favorable low to mid-level moisture convergence coupled with orographic ascent over higher terrain should support the convective threat and locally heavy rainfall rates.
For graphic products and further details, officials suggest visiting www.wpc.ncep.noaa.gov.
