Flood watches have been issued for all of Arizona, including metro Phoenix and Tucson, effective from late Tuesday morning until late Wednesday evening.
Increasing tropical moisture will produce showers and thunderstorms capable of producing heavy rainfall, with the threat increasing Tuesday afternoon and continuing into Wednesday, the National Weather Service said.
Ben Peterson with the National Weather Service in Flagstaff says the storms are packing enough punch for the Weather Service to issue a flash flood watch for the entire state.
“We had a decaying tropical system named Nora down in the Gulf of Mexico, and that created a lot of cloud cover and serene cold air and when that happens over the warm gulf waters, we get what's called a gulf surge.”
The flash food watch signals a chance for heavy rain and dangerous water accumulation. Peterson’s advice is to keep your ears open to the latest weather advisories.
Forecasters said locally heavy rainfall of up to 2 inches per hour combined with saturated ground will likely result in flash flooding in normally dry washes, small streams and poor drainage areas.
Low-water crossings are particularly vulnerable to flooding while burn scars from past wildfires are a particular concern because they're prone to flash flooding and debris flow, the weather service said.
The Arizona Department of Transportation said particular areas of concern were southern Arizona, the Tonto Basin in hill country east of metro Phoenix and along U.S. 60 near Globe.
The department said its maintenance crews across the state have been preparing for the expected storms by clearing debris from drainage systems and checking the more than 55 pump stations along Phoenix-area freeways.
Crews also staged heavy equipment in areas prone to flooding to allow faster responses, the department said.
