Area Forecast Discussion
Issued by NWS Tucson, AZ
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Issued by NWS Tucson, AZ
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-- Discussion containing changed information from previous version are highlighted. --932 FXUS65 KTWC 122145 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 245 PM MST Sat Jul 12 2025 .SYNOPSIS...-- Changed Discussion --Above normal temperatures continue through Monday. Increasing monsoon activity is expected in to begin Sunday, initially in areas east and south of Tucson. These chances increase across southeastern Arizona through the work week. As moisture and storm chances increase, temperatures will drop back down to seasonable levels Tuesday onwards.-- End Changed Discussion --&& .KEY MESSAGES...-- Changed Discussion --- Scattered thunderstorm activity Sunday afternoon and evening will likely create blowing dust through areas of Greenlee, Graham, and Cochise counties. Isolated activity may move as far west as the Tucson area Sunday evening. - Increasing chances for monsoon activity is expected this coming work week. Adequate moisture for increased flash flood concerns may arrive by mid-week. - High temperatures transition from above normal through Monday to near or slightly below normal for the remainder of the week.-- End Changed Discussion --&& .DISCUSSION...-- Changed Discussion --A generally quiet day across southeastern Arizona, with the exception at time of discussion coming from thunderstorms over the White Mountains and the high terrain areas of Cochise county. Flat cumulus across much of southeastern Arizona highlights the presence of modest low level moisture but dry air and subsidence in the mid- levels above it, as observed by the 18Z KTWC balloon. The upper level high currently sitting over southern California will continue to usher in dry air aloft today and keep thunderstorm development chances to a minimum. Tomorrow will see a shift in the direction of the mid-level flow aloft from northwesterly to north to northeasterly. Open-wave troughing in the upper levels will dip over eastern Arizona, bringing upper level support for increased thunderstorm development Sunday afternoon. While a major increase in atmospheric moisture isn`t expected with this process, mild moisture advection and synoptic ascent should be adequate to erode the earlier capping inversion. Early Sunday afternoon, thunderstorms will likely build over the White Mountains and Gila National Forest in New Mexico, then push south to southwest. Increased mid-level flow of around 20 knots along with dry air in the mid and lower levels will produce an environment conducive to strong organized thunderstorm outflows, especially where thunderstorm clustering is likely through eastern Graham, southern Greenlee, and Cochise counties. With the 12Z HREF showing consistency in thunderstorm wind gust probabilities, a Blowing Dust Advisory was issued through this area with this forecast shift. HREF neighborhood probabilities (within 40 km of any point) of 45 mph winds are in the 40 to 70 percent range with 10 to 25 percent chances for 60 mph. Thus not only will blowing dust be a concern, but an isolated damaging wind gust potential will also arrive with these thunderstorms. Santa Cruz county also sees similar probabilities for these strong winds, with less confidence in blowing dust. Tucson sits on the western periphery of both thunderstorm and strong gust probabilities as uncertainty remains in how thunderstorm clusters will evolve westward. That said, 12Z guidance shows potential for thunderstorm chances to last well through the evening, increasing overall chances in the Tucson area to around 40 percent for the day. Thunderstorm motions and dry air in the atmospheric column will mitigate any flooding concerns, though brief periods of heavy rains creating street ponding can`t be ruled out. Daily thunderstorm chances are expected to become more widespread through this coming work week as richer moisture sets in. There will likely be day to day variability in chances as some days may work over the atmosphere more than others, but the mid-week period will need to be watched for increasing flash flood risk.-- End Changed Discussion --&& .AVIATION...-- Changed Discussion --Valid through 14/00Z. West to northwesterly winds this afternoon of 10-15 kts, with 15-20 kts and gusts to 30 kts at KSAD. FEW-SCT clouds this afternoon of 8k-11k feet. Slight chance of a thunderstorm near KDUG-KOLS late this afternoon and evening. Winds become light late this evening. Isolated to scattered thunderstorms expected Sunday afternoon and evening east and south of KTUS. Aviation discussion not updated for TAF amendments.-- End Changed Discussion --&& .FIRE WEATHER...-- Changed Discussion --An uptick in monsoon activity is expected beginning Sunday through next week as the upper high shifts to a more favorable location aloft. Temperatures will remain above normal through Monday, then drop back down to near or slightly below normal by mid to late next week. Winds will remain westerly from 10-15 mph, with occasional gusts at or above 25 mph. Afternoon RH values in the low lying areas will be between 10-15% through Monday, then 20-30% through the remainder of the week.-- End Changed Discussion --&& .TWC WATCHES/WARNINGS/ADVISORIES...-- Changed Discussion --Blowing Dust Advisory from 2 PM to 8 PM MST Sunday for AZZ507>509.-- End Changed Discussion --&& $$ Public...Edwards Aviation...Edwards Fire Weather....Edwards Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson