Flash flood watch issued across Arizona as storm heads this way

PHOENIX – Arizona is under a dayslong flash flood watch starting late Tuesday morning, as forecasters warn of incoming storms that could produce 1-2 inches of rain per hour.

The National Weather Service’s statewide flash flood watch will be in effect from 11 a.m. Tuesday until 5 a.m. Thursday.

Scattered showers are expected Tuesday, but once rain starts falling in earnest – after midnight Wednesday – metro Phoenix could get battered, the weather service said.

“It definitely looks like 1-2 inches per hour rate happening somewhere in the city. Even higher rain rates are possible in very localized areas,” Larry Hopper, a meteorologist with the Phoenix bureau, told KTAR News 92.3 FM on Tuesday.

An active wx period is expected across AZ later today & Wed w/widespread showers & t-storms capable of heavy rainfall. Flash Flooding will be the main concern across area watersheds along with localized urban flooding impacts #azwx Full forecast here: https://t.co/QHKPlzM3Cq pic.twitter.com/W8eGxfGxOX

— The Flood Control District of Maricopa County (@FCDFloodInfo) August 31, 2021

A statewide watch doesn’t happen often, Hopper said.

“But when we do get tropical moisture with a pretty impressive disturbance coming in from the west … when those come together they typically can produce quite a bit of rainfall,” he said.

Flagstaff, which has faced flooding and historic rainfall in recent weeks, has a 90% chance of heavy rain Tuesday and Wednesday.

The state issued an emergency declaration in the area because of flood damage caused by rain on the Museum Fire burn scar.

There is a 90% chance of hard rain in Tucson for Tuesday night. That number drops to 70% by Wednesday morning.

The Arizona Department of Transportation said maintenance crews have been preparing for the 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, ADOT said.

KTAR News 92.3 FM’s Jim Cross and the Associated Press contributed to this report.

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