Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
513 FXUS65 KTWC 262103 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 203 PM MST Fri Jul 26 2024 .SYNOPSIS... Daily chances for showers and thunderstorms are expected through the weekend and into next week with the main threats being strong gusty winds and heavy rainfall. && .DISCUSSION...Our active monsoon pattern continues today for a good portion of our forecast area as convection has already developed over the White Mountains and is starting to push southward towards the Upper Gila River valley. In addition, some showers and thunderstorms have formed over the Chiricahua Mountains and are starting across some of the other Sky Islands east of Tucson. Elsewhere, partly cloudy skies east of Tucson and mostly sunny skies to the west of Tucson. Locales from Tucson westward still have convective inhibition due to the atmosphere being worked over from convection last night. Latest HRRR/CAMs all in good agreement showing a continuation of scattered shower and thunderstorm activity across Graham/Greenlee/Cochise Counties the rest of this afternoon with little if any convection from Tucson westward. It`s generally going to take additional lift from outflows from the east to northeast to help initiate convection from Tucson Metro and points westward during the evening hours. Some of the HREF members are showing the potential for convective activity even well into the overnight hours but confidence is low on that at this time. Bottom line is the main threat with showers and thunderstorms today into tonight continues to be areas of heavy rainfall with a flash flooding threat and gusty winds. For Saturday, the weakening mid/upper level high will be located across southern Arizona and that will result in a weaker steering flow pattern for us. However, with plenty of moisture in place (PWAT 1.25" eastern areas to 1.75" western areas), scattered slow moving showers and thunderstorms will develop. We do expect the bulk of the activity to be from Tucson south and eastward. That area of high pressure will move to our east Sunday into next week opening the area into a more southerly to southeasterly flow pattern. Ensembles are showing some hint of an inverted trough to our southwest around next Tuesday and Wednesday that could help enhance activity. We`ll certainly have enough moisture in place to continue daily scattered thunderstorm activity with the best coverage likely south and east of Tucson. Temperatures will be about 2 to 6 degrees above normal through the forecast period. && .AVIATION...Valid through 28/00Z. SCT-BKN clouds AOA 7-11k ft AGL with scattered SHRA/TSRA mainly east and south of KTUS through 27/00Z, then potentially impacting KTUS area and westward thereafter thru 27/06Z. Low confidence for potential SHRA/TSRA lingering thru the overnight hours till 27/12Z. Additional SHRA/TSRA possible again aft 28/18Z. Strong winds to 40- 60 kts possible near the strongest TSRA with MVFR conditions. Outside of TSRA, surface winds will generally be easterly/southeasterly and remain under 10 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Scattered afternoon and evening showers and thunderstorms with day to day variability on which areas will see the best chance of rainfall. The best chances will typically be from Tucson south and eastward through much of the forecast period. Each day has the threat of heavy rain, localized flash flooding and strong gusty winds. Minimum relative humidities will be 20 to 30 percent in most lower elevation locations and 25 to 40 percent in mountain areas. Away from thunderstorms, 20-foot winds will generally be 15 mph or less, with afternoon/early evening gusts to 20-25 mph and light winds overnight. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson