Arizona Weather Monday: Heavy Rain, Flash Flood Risk

Tucson, AZ – Southeast Arizona is heading into a wetter stretch beginning Sunday, with tropical moisture helping fuel widespread showers and thunderstorms Monday and Tuesday and bringing a risk of flash flooding.

According to the National Weather Service in Tucson, moisture associated with hurricanes Odalys and Polo will move into the Desert Southwest over the next several days. Forecasters emphasize that the remnants of Polo are not expected to directly impact Arizona.

The first increase in moisture will come Sunday as mid- and upper-level moisture from Odalys moves into the region. That could produce a slight chance of light showers, mainly west of Tucson.

More significant tropical moisture is expected Monday and Tuesday as moisture moves north through the Gulf of California into southern Arizona, aided by Polo near southern Baja.

At the same time, a trough of low pressure is forecast to move across Arizona from Monday afternoon through Tuesday night. Combined with deep tropical moisture, the system is expected to produce widespread showers and thunderstorms across Southeast Arizona.

Rainfall should generally be light to moderate Monday, although pockets of heavy rain are possible. More widespread moderate to heavy rainfall could develop Tuesday as the trough crosses the region.

The Weather Service identifies a slight risk for flash flooding Monday and Tuesday, meaning residents should monitor changing conditions, particularly around washes, low-water crossings and other flood-prone locations.

The upper-level system is expected to exit Southeast Arizona early Wednesday, bringing the multi-day period of unsettled weather toward an end.