Valley faces 1 more day of rain, possible flooding before storms run their course

PHOENIX – The metro Phoenix forecast calls for a fifth consecutive day of rain on Monday, and it won’t take much to trigger potentially dangerous flash flooding.

“We still have a lot of lingering moisture in the low levels,” Gabriel Lojero of the National Weather Service (NWS) told KTAR News 92.3 FM. “And so, that’s going to combine with the daytime heating to result in the development of showers and storms as we head into late this morning into this afternoon across portions of the area.”

A flood watch remains in effect across the Valley until 8 p.m. Monday. The NWS could also issue localized flash flood warnings as the day progresses in areas impacted by significant downpours.

Radar showed storms capable of producing strong wind gusts and hail moving north into the area near Chandler before 12:30 p.m.

“These thunderstorms will be capable once again of producing very heavy rainfall rates,” Lojero said.

Soaked ground makes flooding more likely

Under typical dry conditions, a downpour of 1-1.5 inches can set off flash flooding, Lojero explained. But it won’t need nearly that much on Monday for floodwaters to rise.

“Given how saturated the soils is, any heavy rainfall that flows will become instantaneous runoff, and so it may take probably 1/2 an inch to 3/4 of an inch to get flash flooding,” Lojero said.

Monday’s metro Phoenix forecast calls for totals ranging from 1/10 to 1/4 of inch, but amounts could be higher in areas where thunderstorms develop.

“It’s very essential that people are weather aware later this morning and this afternoon for the development in the thunderstorms, and whenever a warning is issued, to take action, move to higher ground, and, most importantly, don’t drive through flooded roadways, because you never know how deep that water is,” Lojero said.

Sunday was Phoenix’s rainiest day in seven years

A total of over 4 inches of rain came down in the past week in parts of the East Valley, including near Greenfield Road and US 60 in Mesa and further east in Gold Canyon, according to the Maricopa County Flood Control District map.

While much of Phoenix proper received 1-2 inches, the city’s official total is even higher. Phoenix Sky Harbor International Airport, which the NWS uses for the city’s official readings, checked in with 3.06 inches since Thursday.

In fact, Sunday was Phoenix’s wettest day since 2018, with a daily record 1.97 inches. Saturday also set a daily records with 0.70 inches.

A search for a missing man was launched Sunday morning after floodwaters swept away his truck near 214th Avenue and Narramore Road in the southwest Valley.

What’s in the Phoenix forecast for rest of week?

Looking ahead, Monday could be the last day the Valley sees rain this month, Lojero said.

“We’re going to have much drier air moving in as we head into this evening and into Tuesday, and so that’s going to complete our rain chances across the region,” he said.

Temperature-wise, the metro Phoenix forecast for the rest of the week calls for cooler-than-normal daily highs in the upper 70s and lower 80s with overnight lows in the lower 60s. The mercury typically peaks at about 90 degrees in mid-October.

KTAR News 92.3 FM’s Colton Krolak contributed to this report.

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