Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
221 FXUS65 KTWC 082121 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 221 PM MST Tue Sep 8 2026 .SYNOPSIS... Isolated to widely scattered thunderstorms this afternoon and this evening, especially along the International Border to the southeast of Tucson. A more active thunderstorm pattern for Southeast Arizona develops Wednesday into Thursday. The primary hazard with these storms will be heavy rainfall leading to localized flash flooding with a secondary hazard of strong outflow winds. High temperatures will will fluctuate between near normal and a few degrees below normal. && .DISCUSSION... Coverage remains isolated at this hour, but there should be an uptick in activity through the afternoon. Main TS risks for today are gusty outflow winds to 35 mph+, lightning, and heavy rain. There could be some nuisance flooding this afternoon into early evening, but nothing widespread expected. WPC maintains a Marginal Risk for Excessive Rainfall today. Wed/Thu look to be more active as high pressure elongates west to east across central AZ/NM brining modest SE/E flow to the region. This will aid in storm development with plenty of moisture and instability around. WPC has bumped up SEAZ to a Slight Risk for Excessive Rainfall, which aligns well with CAMs. While severe probabilities are low at this time, with the increased flow there should be at least some organization into the lower deserts. This should help some of the stronger storms to have wind speeds eclipsing 50 mph with small hail. Isolated instances of flash flooding will also be possible both days. While activity trends down into the weekend, enough moisture/instability will remain for daily shower/storm chances. They will generally favor areas south and east of Tucson. && .AVIATION /20Z TUESDAY THROUGH 20Z WEDNESDAY/... VFR at all TAF locales through the forecast cycle. VCTS for KOLS/KDUG this afternoon with KTUS on the northern edge of better VCTS chances. Shower/storm activity gradually wanes through the evening, but VCHS and perhaps VCTS could linger in into the early morning hours for some. SFC winds generally around 5-10 KTS with a few gusts to 15 kts. Higher in and around TS. A more active shower/storm day expected tomorrow, with more scattered coverage and stronger storms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Isolated to widely scattered thunderstorms this afternoon and this evening, especially along the International Border to the southeast of Tucson. A more active thunderstorm pattern for Southeast Arizona develops Wednesday into Thursday. The primary hazard with these storms will be heavy rainfall leading to localized flash flooding with a secondary hazard of strong outflow winds. Temperatures will be around normal to a few degrees below normal into early next week. Min RH values mainly 20 to 45 percent in the valleys and 30 to 60 percent in the mountains over the next week. RH recoveries will continue to be excellent each overnight. Winds will generally remain less than 15 mph and terrain driven through the week. Expect gusty and erratic winds around thunderstorms. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Visit us on Facebook, X, YouTube, and at weather.gov/Tucson