Tropical moisture from Hurricane Polo will push thunderstorms into the Cottonwood Heights area starting Sunday, Sept. 27, raising flash flood concerns.

Showers and storms are expected to continue through Tuesday, Sept. 29, before drier weather returns.

An upper-level low moving across California and the Great Basin is pulling moisture north from Hurricane Polo, still a hurricane off the coast of Mexico, according to ABC4 Utah meteorologist Noah Price. Some moisture from Hurricane Odalys is also contributing to the system.

The Weather Prediction Center (WPC) placed areas along and south of Interstate 80 in a 15% Slight risk zone for flash flooding. That zone includes Salt Lake City and Cottonwood Heights. Farther south, the WPC issued a Day 3 Moderate risk of excessive rainfall for southern Utah, which ABC4 reported was the first time that designation had been issued for the region.

"This is an impressive surge of moisture we'll be seeing which will produce some heavy rainfall totals and the likelihood for flash flooding," Price said Sunday, Sept. 27.

The National Weather Service forecast for Cottonwood Heights calls for a slight chance of thunderstorms Sunday night with a low of 58°F, followed by a chance of showers Monday, Sept. 28, with a high of 74°F. Monday night's low drops to 52°F with continued shower chances. Skies clear Tuesday. Sunny, dry conditions return Wednesday, Sept. 30, with highs climbing back toward the mid-70s.

NWS Salt Lake City issued a Flood Watch from Monday, Sept. 28, morning through early Tuesday, Sept. 29, morning for much of central and southern Utah. The heaviest storms could bring rainfall rates of 1 to 2 inches per hour, according to NWS forecasters. The watch specifically named burn scars from recent wildfires as the highest-risk areas for flooding.

No formal Flood Watch has been announced for the Cottonwood Canyons in Salt Lake County. The NWS warned that slot canyons, dry washes and burn scars face elevated danger during this type of storm. The Bureau of Land Management issued general canyon safety guidance on Sept. 14 during monsoon season, cautioning that rain upstream can flood a canyon without warning.

Cottonwood Heights serves as a gateway to the Cottonwood Canyons, which draw roughly nine million visitors a year. ABC4 advised anyone planning to visit Utah's national parks Monday, Sept. 28, or Tuesday, Sept. 29, to consider alternate plans. For those heading into canyon terrain, forecasters recommended carrying a way to receive weather alerts, avoiding solo travel and moving to higher ground if a Flash Flood Warning is issued.

Residents can monitor conditions through NWS Salt Lake City and sign up for emergency alerts through Salt Lake County's notification system.