No rainy relief from summer heat yet, but storms are likely later in the week

Phoenix saw a trace of showers Monday morning, but the relief from summer heat was short-lived. The droplets mostly evaporated in the dry air, and now meteorologists are predicting a 100th straight day without rain.

Storm clouds have circled elsewhere this monsoon season but left the Valley parched.

All that could change this week as the Phoenix area sees a 20% chance of showers and thunderstorms starting Wednesday night, according to forecasts from the National Weather Service. Thursday and Friday evenings and parts of Saturday could be stormy, too, forecasts say.

The 20% odds may not seem like much, but meteorologist Bianca Feldkircher said the chances are some of the best she’s seen all summer. Monday’s lackluster clouds could morph into a show-stopping, monsoon-style thunderstorm later in the week.

Of course, the Weather Service can’t make any promises — “But we are getting a little more confident” that storms are on the way, Feldkircher said.

A vast column of air over the Phoenix area needs to moisten before storm clouds can drop heavy rain, Feldkircher said. Early in monsoon season, the air closer to the ground often stays dry and absorbs any falling rain.

The chance of storms should increase through August and September, when tropical activity brings more persistent humidity to the Phoenix area.

“Right now it’s really off and on,” Feldkircher said. “We’ll have maybe one day where we have a good enough amount of moisture, and then it’ll just dry out.”

Arizona is behind schedule for what weather experts consider a “normal” monsoon season. In a typical July, more than half an inch of rain would have already fallen on Phoenix. And while Flagstaff and Tucson have had a few storms this summer, both are about an inch behind what meteorologists expected for rainfall at this point in the month.