Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
727 FXUS65 KTWC 121015 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 315 AM MST Wed Aug 12 2026 .SYNOPSIS...The combination of a shifting weather pattern aloft and deep moisture residing across the region will result in scattered showers and thunderstorms across Southeast Arizona with the potential for heavy rain the next few days. Although most of the storms will produce between a half and one inch of rain, the stronger storms are capable of producing locally heavier amounts between 1-3 inches. Otherwise, a drier southwest flow aloft will bring a downturn in daily storm activity Friday into the weekend. High temperatures will be near normal today, then 3 to 6 degrees below normal tomorrow and Thursday before temperatures warm again into the weekend. && .DISCUSSION...Considerable cloud cover over the area as of 3 am with scattered showers and thunderstorms, some of which have been rather efficient producing heavy rain with PWATs between 1.30" and 2". Confidence low with forecast evolution as the day progresses and the extent of flash flooding as any storms will be efficient rain makers. Current cloud cover, morning showers/storms and possible MCV may delay the start of afternoon convection and push it more toward this evening. Another factor is possible weak upper level disturbance, that was over southern Sonora MX last night, moving across the area under southern flow as it shifts today to become more southwesterly. Per conference call earlier this AM with WPC and the offices from AZ/NM/UT/NV the SLGT risk for Excessive Rainfall was expanded at across most of SE AZ and the state. Due to my low confidence about how today will evolve, all models don`t have the answer and they muddy the waters, I decided against hoisting Flash Flood Watch Tonight: As the southwesterly flow aloft increases as an upper level trof moves into the west coast, there is the potential for another overnight period of showers and thunderstorms, with the focus being across Pinal, Graham and Greenlee counties. Friday into this weekend: A downturn in daily thunderstorm is expected as drier air pushes across the area under southwest flow aloft. Isolated thunderstorms at best, and mostly east and south of Tucson of Tucson. Early next week: Possible slight uptick in thunderstorms associated with easterly wave passing by across northern MX. Confidence low. Temperatures will be about 3 to 6 degrees below normal today and Thursday, with warming thereafter to above normal values for this weekend. && .AVIATION...Valid thru 13/12Z. SCT-BKN 8-12k ft AGL thru much of the valid pd. SCTD -SHRA/-TSRA with isold vsbys 1SM +TSRA. Gusty erratic winds of 35-45 kts possible with any thunderstorm. Outside of storms SFC winds WLY/NWLY at 8-12 kts with ocnl gusts to 20 kts this aftn and evening. SFC winds light and terrain driven after 12/06Z. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...The combination of a shifting weather pattern aloft and deep moisture residing across the region will result in scattered to numerous showers and thunderstorms across Southeast Arizona with the potential for heavy rain the next few days. Although most of the storms will produce between a half and one inch of rain, the stronger storms are capable of producing locally heavier amounts between 1-3 inches. Otherwise, a drier southwest flow aloft will bring a downturn in daily storm activity Friday into the weekend. Minimum relative humidity will be 20-40 percent through Thursday lowering to around 15-30 percent thereafter. Temperatures will be near normal through Tuesday, dropping to below normal Wednesday and Thursday, then warming again next weekend. Outside of thunderstorms, winds terrain driven to around 10 mph with occasional afternoon gusts to 20 mph. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook, X, YouTube, and at weather.gov/Tucson