Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
052 FXUS65 KTWC 141634 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 934 AM MST Mon Sep 14 2026 .SYNOPSIS...An active week ahead with daily chances of showers and thunderstorms. Elevated precipitation chances today with a Flash Flood Watch for portions of southeast Arizona. Daily high temperatures will fluctuate between near normal and a few degrees below normal. && .UPDATE...Latest visible satellite imagery shows mostly clear to partly cloudy skies across southeast Arizona with some residual early morning shower and thunderstorm activity dissipating over Graham County at this time. Cumulus clouds are already starting to form which portends to an active day with SPC mesoanalysis indicating MLCAPE values as high as 2000 to 3000 J/KG with dissipating CIN over the next few hours as daytime heating continues. Latest CAMs focus on locales from Tucson north and eastward for the highest storm chances this afternoon which is reasonable based on latest trends. Main concern will continue to be locally heavy rainfall with flash flooding potential with a secondary wind threat. Current forecast is in good shape. No updates this morning. See previous discussion for additional information. && .DISCUSSION...A persistent moist southerly flow aloft on the western flank of the upper ridge to our east will keep anomalously high PWAT values for September across the area through at least Thursday. There will be daily threats of rainfall rates between 1-2"/hr, possibly higher, with some of the stronger thunderstorms that develop this week leading to elevated chances of flash flooding each day through Thursday. WPC EROs for Days 1-4 (Mon-Thu) have slight risk for excessive rain each day across much of the forecast area. The potential wet week ahead may lead to some enhanced flows in washes, creeks, and rivers that are already saturated. Today: Early morning satellite imagery showed considerable cloud cover across the eastern half of the forecast area with clear skies across western half of Pima county. There will be isolated weak, not long lived, showers popping up this morning. With the increased threat for heavy rain and localized flash flooding from scattered showers and thunderstorms, a Flash Flood Watch is in effect for much of the area today from 11 am to 11 pm. Tuesday: Areal coverage of storms likely down versus today. Wednesday: A disturbance moving out of Sonora MX will bring a more active day versus Tuesday. Thursday: Not as active as Wednesday. Friday into this weekend: Drier air pushes in under westerly flow aloft, resulting in reduced precipitation chances. High temperatures will be right around normal. 8 to 14 day outlooks (Mon Sep 21 to Sun Sep 27) Temperature: Leaning above normal, 44-45% chance Precipitation: Likely above, 49-52% chance && .AVIATION...Valid thru 15/12Z. SCT-BKN clouds 8k-10k ft AGL for much of valid pd with layers clouds above. ISOLD -SHRA thru 14/17z, then SCT SHRA/TSRA aft 14/18z thru 15/04z. Outflow winds nr TSRA of 35-45 kts. VSBYs down to 1SM nr strongest TS. SFC winds terrain driven less than 10 kts thru 14/16z then again after 15/04z thru end of valid pd. Btwn 14/16z and 15/04z SFC winds SLY/SWLY SFC winds 6-12 kt. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...An active week ahead with daily chances of showers and thunderstorms. High temperatures will fluctuate between near normal and a few degrees below normal. Min RH values mainly 20 to 45 percent in the valleys and 35 to 65 percent in the mountains over the next week. RH recoveries will continue to be excellent overnight. Winds will generally remain less than 15 mph and terrain driven. Gusty and erratic winds will accompany thunderstorms. && .TWC WATCHES/WARNINGS/ADVISORIES... Flood Watch from 11 AM MST this morning through this evening for AZZ503>509-511>514. && $$ Visit us on Facebook, X, YouTube, and at weather.gov/Tucson