NWS Forecast Office Phoenix, AZ

Storms today will be capable of producing flash flooding, driven by high rainfall rates. The Weather Prediction Center has expanded the Moderate Risk (3/4) of excessive rainfall (at least 40% chance of flash flooding within 25 miles of a point) further west, including the majority of Maricopa County and all of the Phoenix Metro area. Additionally the Marginal Risk (1/4) and Slight Risk (2/4) were also extended westward. The Marginal Risk now extends to the Lower Colorado River Valley and the Slight Risk extends to central La Paz and Yuma Counties.

Multiple rounds of showers and thunderstorms are likely across Central AZ throughout the day today. Thunderstorms will be capable of efficient, heavy rain rates of upwards of 1-2" per hour. Multiple storms tracking over the same spot poses the greatest threat for flash flooding. In the rainfall probabilities above, you'll notice good odds for 1"+ across a rather broad area, and then a much more focused area mostly E/NE of Phoenix with 10-50% probabilities for 2"+ totals. However, this does not mean that everyone with chances for 1-2"+ totals will receive this much rain, and some areas may miss out entirely or only receive a few tenths of an inch. This is why we have also included probabilities of receiving less than 0.5" (far left); to show that not all areas will see heavy rainfall, and odds of rainfall less than 0.5" increase towards Southwest AZ and Southeast California.

Lingering isolated to scattered showers and storms will be possible overnight tonight through Thursday morning. Any thunderstorms will have locally heavy rainfall that could case additional flooding or worsen any ongoing flooding.

Showers and thunderstorms will be increasing across the region throughout the day today. Best chances will be during the afternoon and evening hours. A Flood Watch is in effect for Maricopa, Pinal, and Gila, most of La Paz, and northern Yuma Counties. Showers and storms will linger into the overnight hours and through Thursday morning before drier air moves in. Dry conditions are then expected through at least the weekend. Near to below normal temperatures will continue through the end of the workweek before increasing to slightly above normal this weekend.