PHOENIX, AZ — A significant rain and flooding event is expected to move into Arizona from Saturday evening through early Monday, bringing the highest concern for flooding and the chance of embedded storms. Forecast guidance points to the most intense impacts arriving Sunday, when rain is expected to be most widespread and persistent across parts of the state.
The heaviest totals are forecast in central and eastern Arizona, with Gila County singled out as the main focus. Forecasters say some locations in that area could see several rounds of rain, raising the risk that runoff and flooding become the biggest threats of the weekend system.
Gila County faces the highest rain totals in the weekend setup
The forecast highlights a 3- to 5-inch rain potential from Saturday evening through Monday morning in the areas with the greatest impact. That does not mean every community in the region will receive that much rain, and it does not suggest a single storm will drop that amount all at once.
Instead, the concern is that multiple waves of rain may move over the same places during the event. That pattern would allow rainfall to add up over time, which is why flooding is listed as the top hazard. The forecast also notes that some surrounding areas may stay in the half-inch to 2-inch range, which is still enough to create runoff problems if the rain falls repeatedly.
Central Arizona is favored for the strongest storm ingredients
The setup is being driven by an upper-level pattern that supports storm growth over Arizona. Forecasters point to diffluence aloft over central Arizona, which helps air rise and can give storms room to develop and strengthen.
Moist southwest flow in the middle and lower levels is also expected to feed the system. That influx of moisture, combined with positive vorticity advection, terrain effects, and weak to moderate instability, gives the atmosphere enough energy for organized rain and thunder potential. The forecast also mentions some low- to mid-level wind shear, another ingredient that can help storms become more intense in spots.
Sunday carries the greatest chance for embedded severe storms
Although flooding remains the main concern, Sunday is the day forecasters see the best chance for embedded storms to produce more intense weather. Those storms could bring convective wind gusts up to 60 mph and hail as large as 1 inch in diameter.
The risk of a funnel cloud or tornado is described as very isolated, but it is not zero. That means most places will not see severe weather of that kind, yet a few stronger cells could briefly become capable of producing dangerous conditions inside the broader rain event.
Rain should begin Saturday night and ease by Monday morning
The timing of the system matters as much as the totals. Light rain is expected to move in Saturday evening, then gradually increase overnight into Sunday. By Sunday, the region should see the most active period of the event, with rain continuing through the evening in many places.
Conditions are then expected to taper off and move east by Monday morning. Because the rain may come in rounds rather than one short burst, forecasters are urging travelers and anyone planning outdoor activities to keep checking radar and the latest forecast through the weekend.
Forecasters warn against crossing flooded roadways
The safety message from the forecast is straightforward: flooding is the number one issue, and roads can become dangerous fast when rain keeps falling over the same area. Drivers are being told not to cross flooded roadways, even if the water does not look deep.
The warning also applies to people spending time outdoors or traveling through the state during the event. Forecasters say the combination of heavy rain, possible thunderstorms, and localized flooding could make conditions hazardous in a short time, especially in low-lying or storm-prone areas.
A longtime Arizona forecaster says the system could be significant
The outlook was shared by Michael Bielas, known as the Arizona Weatherman, who has more than 25 years of experience in aviation meteorology. His background includes work with the U.S. Air Force, government contracting, and private practice, along with training Special Operations Weather Technicians.
He also describes himself as an Arizona STEM-certified teacher and publishes weather analysis through a free Substack newsletter. In this forecast, his message centers on the same main point: the weekend system looks dangerous enough to deserve close attention, especially because flooding can develop quickly when repeated rain bands move across the same communities.