Arizona’s 2017 monsoon is well underway.

Here are the latest updates on storm activity and forecasts affecting the Phoenix metro area.


July 20, 7:10 p.m.: Rain moves into Scottsdale, northern Phoenix, NW Valley

Heavy winds and rain fell in northern parts of the Phoenix metro area early Thursday evening, including areas of Glendale, north Phoenix and Scottsdale.

All northern regions of Phoenix should anticipate rain and 30 to 40 mile-per-hour winds, according to the National Weather Service.

So far, 0.47 inches of rain have fallen in Phoenix this month, the National Weather Service said.  NWS expects chances of rain to subside in the Phoenix area Friday through Sunday but increase again Monday.  

July 19, 7:15 p.m.: Mayer hit by rain, neighboring towns issued flash flood warning

Rainfall made its way to northern Arizona as it hit Mayer and neighboring towns of Spring Valley and Cordes Lake.

The National Weather Service issued a flash flood warning 


July 19, 2 p.m.: Rain falls in southwest Valley 

Residents of Goodyear and other parts of the southwest Valley saw rainfall from an early-afternoon storm.

The National Weather Service reported storms and showers with heavy rain and blowing dust in the western parts of Maricopa County and in the Phoenix-metro area.

The weather service forecasts a 20 percent chance of thunderstorms this afternoon and a 30 percent chance on Wednesday night.

July 18, 4:50 p.m.: Storms now bringing rain in West and East Valley

The National Weather Service reported storm cells were developing in the West Valley, bringing rain to areas to both the north and south.

The storms developed as storms began moving into the area from the east, as light rain was falling in areas of the East Valley.

July 18, 4:30 p.m.: Flash flood warning issued east of Phoenix, storms moving into eastern areas of metro Phoenix

The National Weather Service issued a flood advisory near Roosevelt Lake and the Superstition Mountains and a flash flood warning near the towns of Tonto Basin and Roosevelt on Tuesday after heavy rains in the area — and those storms are moving into the Valley from the east.

The flood advisory goes until 6:45 p.m. on Tuesday night. NWS advises residents to immediately move to a higher ground and avoid walking or driving through flooded areas.

The storms that poured on the Roosevelt and Superstition Mountain areas were moving into the Northeast and Southeast areas of the Valley. 

 NWS had predicted a 40 percent chance of showers and thunderstorms on Tuesday night. By 4 p.m., a wall of dark clouds  was building across the eastern side of metro Phoenix and moving into the metro region. Rain also was developing in the west Valley, NWS said.

NWS has has issued a flash flood watch until 2 a.m. on Wednesday for most of Arizona, with the exception of La Paz and Yuma counties.

July 18, 3:30 p.m.: Storms building east of Phoenix, could move into Valley

Monsoon storms were building east of the Valley Tuesday afternoon and could impact eastern areas of metro Phoenix, the National Weather Service said.

The storms were strongest east of Fountain Hills and extended east toward Roosevelt Lake, the NWS said.

A severe thunderstorm warning had been issued near Roosevelt and Tortilla Flat, expiring at 3:30 p.m.

Earlier in the day, the NWS issued  a flash flood watch for nearly the entire state of Arizona with the exception of Yuma and La Paz counties though 2 a.m. Wednesday.

July 17: Thousands without power after monsoon storms 

Nearly 1,700 customers still were without power Monday morning after a reported 8,000 lost power as two storms collided over the Phoenix area Sunday night, authorities said. 

Nearly all of the Valley saw rainfall, except for an area near Queen Creek, according to meteorologists at the National Weather Service in Phoenix. El Mirage was the hardest hit with slightly more than 2 inches of rain, while much of the Valley received an inch to a half-inch of precipitation.

The second dust storm of the day roared through the Valley just after 9 p.m. followed by the monsoon storms, which caused some downed trees and broken roofs. 

Additional rain is expected Tuesday evening, the weather service said.

July 15, 9:30 p.m.: Storms cleared from the Valley

The storms had cleared out of the Phoenix metro area by the later evening hours after drenching the West Valley and central Phoenix, causing flight delays and diversions at Phoenix Sky Harbor International Airport and shutting down power for nearly 6,000.

Weather officials said the southeastern part of the state could still expect to see rain, but added that it would likely clear out as the evening progresses.

A National Weather Service radar map showed the most severe weather at 9 p.m. was near Benson, about 45 miles southeast of Tucson.

July 15, 6:15 p.m.: Rain, hail hits central Phoenix

The storm made its way to central Phoenix just after 6 p.m., with the Arizona Department of Transportation reporting heavy rains falling from the Stack to the Loop 202 in Tempe.

Some hail was spotted on the Interstate 10 near 27th Avenue just after 6:15 p.m., ADOT reported. 

July 15, 6 p.m.: Road closures in Surprise, Peoria

Surprise and Peoria public safety officials were reporting multiple road closures due to the storm, most because of downed trees or power lines in the road. Here are areas to avoid:

  • Dysart Road at Grand Avenue.
  • Southbound Bullard at Tierra Buena.
  • 98th Avenue and Deer Valley Road.
  • Westbound Bell Road at Westpoint Parkway.
  • Westbound Bell Road at Mountain View Boulevard. 
  • Westbound bell Road at 165th Avenue

July 15, 6 p.m.: Dust storm hits West Valley

The Arizona Department of Transportation reported there was a dust storm over Interstate 10 in the far West Valley. Drivers were advised to stay off the road.

Drivers already on the road are advised to pull over during a dust storm. 

July 15, 5:30 p.m.: Severe thunderstorm warning in northwest Valley

Weather officials issued a severe thunderstorm warning for the northwest Valley Saturday evening.

The warning includes Glendale, Peoria and Surprise, and lasts until 6 p.m.

The Surprise Police Department reported high winds were blowing trees down across the city. 

Police asked residents to avoid driving, if possible. 

July 15, 5 p.m.: Storms move into the Valley

Storms were making their way toward the Valley early Saturday evening, kicking up wind and dust in areas such as Scottsdale and Coolidge.

Radar maps showed the cells were moving toward the Valley from the north, with heavy rain reported along Interstate 17 near Jomax Road. 

The National Weather Service issued a blowing dust advisory for portions of Pinal County, including along the Interstate 10 corridor. 

The advisory is in effect until 6 p.m. and could bring winds of up to 40 mph.

Visibility in areas affected by blowing dust could be less than one mile, according to weather officials.

July 15, 11:15 a.m.: Officials confirm tornado set down in Marana on Friday

National Weather Service officials confirmed a landspout tornado set down in Marana, north of Tucson, at 6:55 p.m. Friday. Officials had issued a tornado warning in that area.

According to the National Weather Service, a  landspout tornado forms from the ground upward, unlike supercell tornadoes commonly seen in the Midwest that form from the clouds downward. 

July 15, 9 a.m.: Storm damage reported at Lake Pleasant

The Maricopa County Sheriff’s Office reported the Lake Pleasant area received some damage from Friday’s monsoon storm, which produced high winds and choppy water.

Lake patrol deputies helped rescue three juveniles caught in the storm on waverunners and two women on paddle boards. One of the women was not wearing a life jacket and nearly drowned. She was taken to the hospital but was expected to make a full recovery. 

Multiple boats were damaged during the storm, according to the Sheriff’s Office, including several that were totaled. The roof of the Scorpion Bay Marina was partially ripped off and the boat lift in the Sheriff’s Office boat house was damaged. 
July 15, 8:30 a.m.: Weekend thunderstorms to cool things off 

Saturday morning, temperatures in Phoenix reached a low of 89 degrees. The occurrence of thunderstorms was forecast to become more widespread over the weekend and into next week, allowing a reprieve from triple-digit highs. 

Farther south, the National Weather Service in Tucson showed strong and wet storms would have a “marginal” effect through central and southern Arizona. Some were expected to become severe Saturday evening. 

Storm movements will be to the southwest at about 15-20 mph and strong, gusty winds in excess of 50 mph in addition to heavy rainfall may contribute to flash floods.

“May the odds ever be in your favor,” the agency tweeted.

July 14, 7:50 p.m. Severe thunderstorm watch in Maricopa, Pinal counties lifted

The National Weather Service lifted severe thunderstorm watches for  Maricopa and Pinal counties saying the threat “had greatly diminished.”

Heavy storms earlier in the evening were prominent in southern Pinal County near Red Rock, where a tornado warning had expired at 7:30 p.m.

And the first major dust storm of this monsoon season blew through the Phoenix area earlier in the evening, but did not deliver significant rains.

NWS officials have said that the chance of significant storm activity in the Phoenix area is expected to increase this weekend.

July 14, 6:45 p.m. Tornado warning in Red Rock 

The National Weather Service issued a tornado warning for an area along the Interstate 10 corridor near  Red Rock, north of Marana in southern Arizona. 

The National Weather Service said the warning would be in effect until 7:30 p.m.

A blowing dust advisory was in effect along I-10 until 8 pm.

July 14, 5:15 p.m. Blowing dust advisory added as storms move into Valley from north, east

The National Weather Service issued a blowing dust advisory for metro Phoenix as storms continued their push into the Valley.late Friday afternoon.

The advisory is in effect until 7 p.m. There is potential for winds stronger than 40 mph and visibility less than 1 mile.

The advisory came as clusters of monsoon storms moved into the Phoenix metro area from the north, prompting a severe thunderstorm warning for the northwest Valley. Storms also were building in areas near the far southeast Valley moving toward the metro areas.

In addition, 50 mph winds were recorded in the Wickenburg area as another major cell moved though.

The NWS urged drivers to be safe while driving in dust or rain storms.

A flood advisory was also issued in south-central Yavapai County as storms moved into the Valley from the north, the NWS said.

The advisory is in effect until 7:45 p.m. and includes areas near the Valley including Castle Hot Springs, Rock Springs and Black Canyon City. 

July 14, 4:45 p.m. Severe thunderstorm warning for areas northwest of Phoenix

A severe thunderstorm warning has been issued for a large area of the northwest Valley until 5:15 p.m., the National Weather Service said.

The advisory includes Glendale, Peoria, Surprise and Anthem.

In addition, a band of storms were building in areas northeast of the  Valley and moving toward metro Phoenix.

July 14, 11 a.m.: Ozone advisory for Maricopa County

The Arizona Department of Environmental Quality issued an ozone High Pollution Advisory for Maricopa County, effective July 14 and 15.

Ozone levels were expected to accumulate enough to exceed the federal health standard.

People most affected by ozone include children, senior citizens, people who work or exercise outdoors and people with pre-existing respiratory disease. Ozone-related health problems include shortness of breath, coughing, wheezing, headaches, nausea, and throat and lung irritation.

Visit for tips on reducing air pollution.


Ozone is a big deal. Here’s what you should know about this colorless gas that can cause a variety of health issues.

July 13, 6:45 p.m.: Storm approaching Scottsdale

A strong storm was approaching central Scottsdale just after 6:30 p.m., the National Weather Service said. 

The storm was bringing strong winds along with it, with wind gusts of up to 40 mph possible until 7 p.m., officials said.

July 13, 5:30 p.m.: Severe thunderstorm warning for part of Maricopa County

The National Weather Service issued a severe thunderstorm warning for areas of  northeast Maricopa County, including Carefree until 6 p.m.

 Satellite radar was showing strong storms building to the northeast and east of Maricopa County, which could produce outflow winds into eastern areas of Maricopa County.

A flood advisory was issued for areas near the Tonto Basin east of the Valley until 7 p.m., as heavy rains moved through the area.

July 13, 3:15 p.m.: Storms build near Flagstaff, Tucson

The National Weather Service in Tucson and Flagstaff both reported isolated and scattered thunderstorms on Thursday as later-afternoon monsoon storms again built while Phoenix remained dry.

There was a strong thunderstorm rolling over Black Canyon City north of Phoenix, delivering them heavy rainfall and strong winds. Heavy rainfall also occurred on just northeast of Payson.

National Weather Service Tucson said areas northeast of Safford and throughout Santa Cruz County should expect strong storms on Thursday.

The National Weather Service in Phoenix had predicted the chances of storms moving into the Valley would increase over the upcoming weekend. Storms weren’t expected to do much in the Phoenix area Wednesday, but a heavy cell moved through the northeast Valley and another hit part of the northwest Valley.


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July 12: Storms roll through north Valley

A monsoon storm was rolling through northeast Phoenix and northern Scottsdale Wednesday evening, prompting the National Weather Service to issue an advisory.

In addition, a storm was moving through the Surprise area in the northwest Valley.

Severe thunderstorm warnings were issued earlier for areas near Fountain Hills and Rio Verde to the northeast, as well as far eastern Maricopa County near Tortilla Flat, the National Weather Service said.

A National Weather Service tweet said the Scottsdale-area storm was heading southeast and included gusty winds, lightning and heavy rain.

July 12: Old-school monsoon dates

If the old-school method still held, Arizona’s monsoon would have started on July 9.

The old system, last used by the National Weather Service in 2007, looked at the dew-point average to calculate the start of the monsoon.

“We took an average of the dew-points in Phoenix and when they got above 55 degrees … for three days, that is when we started the monsoon season,” Travis Wilson, a National Weather Service meteorologist.

The average dew-point temperature was 60 degrees on July 9, 58 degrees on July 10 and 61 degrees on July 11, Wilson said.

The National Weather Service officially recognizes monsoon season from June 15 to Sept. 30. According to Wilson, every regional office had different methods of determining when the monsoon began, so they decided in 2008 to declare a season by calendar.

“Just because it’s not raining in Phoenix – it takes a little longer for it to moisten up down here – doesn’t mean we’re not in the monsoon season,” Wilson said.

For the past 30 years, the first measurable rainfall of the monsoon in Phoenix has typically fallen around July 4. That didn’t happen until July 10 this year.

Thunderstorms start with three ingredients: an unstable atmosphere, moisture and a trigger. Wilson said that the mountainous regions up north see thunderstorms first and these storms produce “outflows” that travel down to Phoenix, where, if conditions are moist enough, more thunderstorms can be produced.

  • Riding out a monsoon windstorm in Phoenix

    Riding out a monsoon windstorm in Phoenix

  • Images from Friday's Phoenix-area storm

    Images from Friday’s Phoenix-area storm

  • Monsoon storm approaches in far West Valley

    Monsoon storm approaches in far West Valley

  • Time-lapse of monsoon storm thunderhead building over Carefree

    Time-lapse of monsoon storm thunderhead building over Carefree

  • Time-lapse view of monsoon storm from Broadway curve in Phoenix

    Time-lapse view of monsoon storm from Broadway curve in Phoenix

  • Storm downs tree in Gold Canyon

    Storm downs tree in Gold Canyon

  • Watch a dust storm move across the East Valley

    Watch a dust storm move across the East Valley

  • Monsoon rains hit far West Valley

    Monsoon rains hit far West Valley

  • Clouds form over Mount Lemmon

    Clouds form over Mount Lemmon

  • Downtown Phoenix, July 15, 2017

    Downtown Phoenix, July 15, 2017

  • Surprise/Waddell monsoon storm

    Surprise/Waddell monsoon storm

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