Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
291 FXUS65 KTWC 112023 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 123 PM MST Fri Sep 11 2026 .SYNOPSIS...A more active day is forecast across southeast Arizona today with isolated to scattered showers and thunderstorms. Main threat from storms today will be heavy rain and localized flash flooding, especially across Santa Cruz county and southwest Cochise county. A more typical isolated to scattered coverage of storms is forecast this weekend into next week. Daily high temperatures will fluctuate between near normal and a few degrees below normal. && .KEY MESSAGES... -Isolated to scattered showers and thunderstorms this afternoon mainly south and east of Tucson capable of producing potentially heavy rainfall. -Slight Risk (Level 2 of 4) today for excessive rainfall that may lead to localized instances of flash flooding in flood prone areas. Sensitive low water crossings may become impassible. -Above normal moisture for mid September continues over the weekend into early next week resulting in continued chances for showers and storms and a Marginal Risk (Level 1 of 4) for excessive rainfall. && .DISCUSSION...Storms started forming early over high terrain areas including the Huachuca and White Mountains around 11 am MST which was a bit sooner than convective allowing models suggested. Additional storm activity is anticipated to continue this afternoon and evening with the strongest activity mainly focused south and east of Tucson. The primary concerns with storms this afternoon continues to be heavy rainfall (rates 1.0 to 2.5 inches per hour) and frequent lightning. However, gusty and erratic outflow winds to around 45 mph cannot be ruled out with the strongest storms as well. Heavy rainfall may result in isolated instances of flash flooding, especially across Santa Cruz County, southwest Cochise County, and far southeast Pima County. Portions of eastern Santa Cruz county and SW Cochise county has seen heavy rain over the past 72 hours, so the soils are wet, and the San Pedro has had some increased flow several days ago making them more susceptible to saturation this afternoon. Flowing water can be expected in normally dry washes. Sensitive low water crossings may become impassible with swift moving water. Remember to remain alert, avoid driving through flooded roads, and obey road closures. The extent of showers and storms tomorrow will largely depend on how the evolution of storm activity this afternoon and evening. But even if we see less coverage of storms tomorrow, sufficient moisture in place could again be supportive of heavy rainfall. The 11/12Z HREF depicts a slight chance (10-30%) for heavy rain exceeding 2 inches in a 3 hour period across Santa Cruz County and southeast portions of Pima County. Sunday through Thursday monsoonal moisture continues to remain in place daily chances (20-50%) for showers and storms. Otherwise, high temperatures will remain near normal through Monday afternoon before we cool off and highs sag slightly below normal. && .AVIATION...Valid thru 13/00Z. SCT-BKN 6k-9k ft AGL. ISOLD to SCT SHRA/TSRA mainly S and E of KTUS thru 12/02Z and again aft 12/21Z. Isold VSBY 1-3 miles nr TS. Lclzd TS outflow winds of 30-40 kts. Otrw, SFC winds WLY/NWLY at 6-10 kts thru 12/04Z and again aft 12/17Z. At other times, SFC winds will be terrain driven and less than 10 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered showers and thunderstorms today. A more typical isolated to scattered coverage of storms is forecast this weekend into next week. High temperatures will 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...None. && $$ Visit us on Facebook, X, YouTube...and at weather.gov/Tucson