Heavy rain and thunderstorms swept across Phoenix and south-central Arizona on Thursday, September 24, with forecasters warning that tropical moisture from Hurricane Polo could bring another spell of unsettled weather early next week.
Morning storms were expected to ease by mid-morning, leaving behind humid and warm conditions. Cloud cover was forecast to linger, while further showers and thunderstorms remained possible in southern and northern parts of the state.
The National Weather Service said a disturbance moving across Arizona could trigger another round of storms during Thursday afternoon or evening. Phoenix may see fewer storms after the wet start, although communities in the East Valley that missed the first bout of rain could face a greater risk later in the day.
Some storms may produce gusty winds, brief heavy rain and flash flooding, particularly around higher ground and foothill areas. Drivers have been urged not to enter flooded roads, where fast-moving water can sweep vehicles away.
Hurricane Polo could increase Arizona rain chances
Conditions are expected to become drier on Friday and Saturday, with temperatures rising from the mid-90s in Phoenix on Thursday to the upper 90s on Friday and around 100F on Saturday.
Rain chances are then expected to increase from Sunday afternoon through Tuesday as tropical moisture is drawn north from the Pacific and Mexico. The National Weather Service said temperatures could fall noticeably early next week as the moisture reaches the Desert Southwest.
Hurricane Polo was moving west-north-west off the coast of Mexico on Thursday and remained an extremely powerful Category 5 storm, according to the US National Hurricane Centre. Its exact track will determine how much moisture reaches Arizona.
A track closer to the state could produce higher rainfall totals, while a faster weakening or a path farther to the west or east could limit the impact. Forecasters said the outlook would become clearer over the next few days, but some effects in Arizona are increasingly likely from late Sunday onwards.
Residents should remain alert to local weather warnings, particularly if heavy rain develops. Officials advise people to move to higher ground if water begins rising and to stay well clear of downed power lines and flooded washes.
