Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
919 FXUS65 KTWC 210928 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 228 AM MST Fri Aug 21 2026 .SYNOPSIS... Isolated to scattered afternoon and early evening showers and thunderstorms expected today across Southeast Arizona into the weekend. The primary concern with storms will be gusty outflow winds, with locally heavy rain. Otherwise, afternoon high temperatures will remain 5 to 8 degrees above normal through the weekend, with moderate to major HeatRisk. && .DISCUSSION... Quiet tonight with only some weak radar echoes in western NM and thunderstorms well to the south in south-central Sonora. As we move into the afternoon/evening, expect isolated to scattered showers and thunderstorms across much of SEAZ. There is a a very subtle mid and upper level inflection that will move from northern Sonora through SW AZ, which should help with additional support for more scattered storms across Santa Cruz, and central/western Pima County. Tucson Metro will see more isolated activity and even less so further to the east where drier air remains in place. The main threats with today`s storms will be gusty outflow winds generally between 35-45 mph, brief heavy rain and lightning. There could be some stronger storms west of Tucson with winds in excess of 50 mph and localized minor flooding, but not expecting anything widespread. Activity will quickly wane after sunset. By early next week, its becoming increasingly likely of below average Monsoon activity. Best chance for showers/storms will be the higher terrain and along the International Border. As for the heat, moderate to major heat risk remains in the forecast. The Extreme Heat Warning remains in effect through Saturday and its looking more and more likely it could extend into most of next week. && .AVIATION /06Z FRIDAY THROUGH 06Z SATURDAY/... FEW/SCT clouds this morning becoming SCT decks between 10-14kft agl. VCTS/VCHS for KTUS/KOLS this afternoon/evening, with most of the TS west of the airports. Gusty and erratic outflow winds possible near TSRA with gusts to 40 kts. Winds outside of thunderstorms mainly light and terrain driven, with a WLY/NWLY component during the afternoon. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Isolated to scattered showers and storms will return to Southeast Arizona this afternoon. The primary concern with the strongest storms this afternoon will be gusty and erratic outflow winds, locally heavy rainfall, and small hail. Otherwise, storm chances continue through the weekend with day to day variability. Hot daytime high temperatures and elevated overnight low temperatures will persist with an Extreme Heat Warning now in effect for portions of southeast Arizona through Saturday. Outside of thunderstorms, winds will be mainly light and terrain driven. Minimum relative humidities 12-25 percent in lower elevations with 25-35 percent in the higher terrain. && .TWC WATCHES/WARNINGS/ADVISORIES... Extreme Heat Warning until 8 PM MST Saturday for AZZ501-502- 504>506-509. && $$ SYNOPSIS... DISCUSSION...Michael AVIATION...Michael FIRE WEATHER...Michael Visit us on Facebook, X, YouTube, and at weather.gov/Tucson