Phoenix, Arizona: Flood Watch Friday as Two Rounds of Halloween Storms Target the Valley

Phoenix is under a Flood Watch on Friday, October 30, as the first of two rounds of Halloween weekend storms moves across central Arizona, and forecasters say a stronger and wetter system follows on Sunday.

The National Weather Service office in Phoenix placed the Phoenix metropolitan area, rural Maricopa County and northwestern Pinal County under a Flood Watch from 6 a.m. to 6 p.m. Mountain Standard Time on Friday. A watch also covers parts of Gila County on Friday afternoon and evening, and Yavapai County from 10 a.m. to 10 p.m., according to the Arizona Republic.

What Friday is expected to bring

The weather service said showers and thunderstorms could develop around the metro area as early as 4 a.m. Friday and become more widespread by early afternoon, moving from the West Valley through central Phoenix and into the East Valley. Stronger thunderstorms could produce rainfall rates of one to two inches per hour, and localized totals of one to two inches are likely, the Phoenix office said in its Friday morning forecast discussion.

Average rainfall across the metro area on Friday is forecast at about half an inch to one inch, with as much as one and a quarter inches possible in the northern foothills and higher terrain between northern Maricopa, southern Yavapai and northeastern Gila counties, the Arizona Republic reported. A few of the scattered thunderstorms could turn severe in the afternoon, with damaging winds of 60 to 70 miles per hour and large hail possible.

The rain started before dawn farther south. The National Weather Service in Tucson issued a Flood Advisory at 2:26 a.m. for northeastern Pima County after radar showed half an inch to one inch of rain had fallen across parts of Tucson and Marana. Minor flooding was reported in low lying and poorly drained areas, and the advisory expired at 4:30 a.m.

A second, wetter round on Sunday

Halloween on Saturday is expected to stay mostly dry in Phoenix, with a forecast high near 78 degrees, FOX 10 Phoenix reported. The break does not last. A second flood watch takes effect at 11 p.m. Saturday, October 31, and runs through 5 a.m. Monday, November 2, covering most of Arizona, including Maricopa and Pima counties.

The weather service briefing said the second system is stronger and wetter, with average rainfall of one to one and three quarter inches possible on Sunday and localized amounts of two to two and a half inches favoring the northern and eastern portions of Phoenix. The Weather Prediction Center has placed the Four Corners region under a moderate risk of excessive rainfall for November 1, because the rain will fall on ground already soaked by the Friday storms.

What drivers should do

A flood watch means flooding is possible, not that roads have already flooded. Water can cross normally dry desert washes, flood channels and low water crossings quickly in this terrain, and forecasters advise drivers never to cross a flooded road. Road conditions are posted through Arizona 511, and the weather service offices in Phoenix and Tucson will update watches and warnings through the weekend.

Sources: Arizona Republic flood watch report, October 30, 2026; FOX 10 Phoenix weather forecast, October 29, 2026; National Weather Service Phoenix briefing, October 29, 2026, and forecast discussion, October 30, 2026; The Watchers Four Corners flood watch report, October 30, 2026.