Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
235 FXUS65 KTWC 121956 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 1256 PM MST Fri Sep 12 2025 .SYNOPSIS... Scattered afternoon and evening thunderstorms will continue today mainly near and east of a line from Dudleyville through Tucson and Nogales. Thunderstorms may linger longest overnight through Graham, Greenlee, and Cochise counties. An isolated risk of strong winds, large hail, heavy rain, and blowing dust will accompany these thunderstorms. Dry air begins to push in Saturday with thunderstorm chances lingering south and east of Tucson, with a dry forecast on Sunday. Temperatures transition from below normal this weekend to above normal next week with a modest return of thunderstorm chances. && .DISCUSSION... An active thunderstorm day is expected to develop this afternoon across much of southeastern Arizona, especially from central- eastern Pinal/Pima to Santa Cruz and eastward. Healthy 1500-2500 J/kg of MLCAPE and 20- 30 knots of 0-6 km shear will produce an environment capable of longer lasting individual thunderstorm cells capable of damaging wind gusts, hail, and heavy rainfall. With a deep upper level trough to the west, ample forcing/ascent exists for thunderstorm development through the late evening and lasting potentially through the overnight hours, especially in eastern locations. Looking at the western edge of the environment capable of these thunderstorms, mid-level moisture has pushed a bit further west through Tucson compared to where it was just 24 hours ago (as indicated by the Advected Layered Precipitable Water product). This will subsequently bring greater thunderstorm chances further west than yesterday, including southward through Nogales and north through central-eastern Pinal. Strong flow oriented from southwest to northeast will push thunderstorms that form over the Catalinas away from Tucson, so impactful storms in Tucson will likely need to form to the west or south...if not over town. This weekend, the western trough will make its trek eastward across the Four Corners region, dragging moisture mostly out of southeastern Arizona with it. Moisture should linger in far southeastern and eastern, keeping chances mainly to Cochise, Santa Cruz, and southern Graham/Greenlee counties on Saturday. Then Sunday moisture should push out enough to keep a dry forecast for the day. With this trough crossing temperatures will dip below normal for the weekend. Following the trough passage, a ridge centered to the south is expected to build and bring at least some moisture back into the region early next week. There remains some discrepancies in how well moisture returns, so chances remain modest and mainly to the south and east of Tucson (in the 10-30 percent range on Tuesday). && .AVIATION... Scattered thunderstorms expected this afternoon near and east of KTUS-KOLS through the afternoon and evening, with greater chances in Graham, Greenlee, and Cochise counties. Should diminish in western areas such as KTUS- KOLS after 13/04Z, lingering through the overnight hours in eastern terminals such as KSAD- KDUG. An isolated risk of wind gusts to 50 kts and large hail will accompany any thunderstorm, along with very heavy rainfall and mountain obscurations. Otherwise, SLY/SWLY SFC wind at 10-16 kts with gusts to 20-25 kts thru 13/04Z. SFC wind less than 10 kts and variable in direction at other times. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Minimum RH values will be in the 20-35 percent range through Saturday, lowering into the 15-30 percent range Sunday and Monday. Scattered showers and thunderstorms are expected from the Tucson area eastward today, with a chance of showers and thunderstorms mainly for Cochise County and east Santa Cruz County Saturday. Thunderstorms today will have a risk of very strong gusty winds, large hail, and very heavy rainfall. Dry area- wide Sunday, then a slight chance of thunderstorms south and east of Tucson return again next week. Outside of thunderstorm outflows, expect 20-foot winds to be 15 mph or less, with some afternoon/early evening gusts to around 25 mph. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Public...Edwards Aviation...Edwards Fire Weather....Edwards Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson