Ileana is currently barreling toward Mexico’s Baja California peninsula, where it will bring tropical storm-strength rain and wind as it moves toward mainland Mexico. While it’s expected to die out before it reaches land, Phoenix and other parts of Arizona will feel its effects.
The storm is expected to “essentially decay” over the next 24 to 36 hours and “turn into an extratropical depression,” National Weather Service Phoenix Meteorologist Mark O’Malley told Phoenix New Times.
“The moisture associated with the system will stream northward toward Arizona over the weekend,” O’Malley said. “That’s going to present chances for showers and thunderstorms across the southern part of the state late in the weekend.”
A wide swath of the state, ranging from Tucson through Phoenix and up to Show Low, has a 50-70% chance of rain over Sunday and Monday.
The rain will be less than torrential, though. O’Malley said those areas should receive up to “a half an inch to an inch of rain,” with the mountains northeast of Phoenix potentially experiencing “a little more.” It’s also possible — about a 10% chance, O’Malley said — those areas won’t get any rain.
“There’s a lot of hit and miss,” O’Malley said.
Temperatures will trend down over the weekend and into early next week, thanks to multiple troughs of low pressure moving through the Western U.S. Forecast highs are in the 90s during the entire upcoming work week for Phoenix. #azwx #cawx pic.twitter.com/FBqiSxSMgV
— NWS Phoenix (@NWSPhoenix) September 13, 2024
But rain or no rain, cooler temperatures are coming to Phoenix.
According to O’Malley, Ileana coming from the south combined with another storm system from the north will cause temperatures to fall over the next several days and into early next week. Phoenix is “expecting a lot of cloud cover” and moisture in that stretch, and O’Malley said high temperatures “should only be in the upper 80s to lower 90s” by Tuesday.
That would be a lower temperature than is normal for this time of year in the Valley. Typically, mid-September still means temperatures above 100 degrees.
Despite cooling temperatures, triple-digit days will likely return before long. “Phoenix typically does not see its last 100-degree day until the beginning of October,” O’Malley said. In late August, NWS Meteorologist Alex Young estimated Phoenix’s last 100-degree day to be Oct. 5 this year.
