224 FXUS65 KTWC 011615 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 915 AM MST Fri Aug 1 2025 .SYNOPSIS...A drying trend with continued above normal temperatures through this weekend. Still enough moisture for isolated thunderstorms from Sells eastward today, then south and east of Tucson Saturday with dry air overtaking all of southeast Arizona Sunday. Thereafter, below normal monsoonal activity is expected next week. Extreme heat will continue through the weekend and perhaps continuing through much of next week as temperatures remain well above normal. && .UPDATE...Abundant sunshine this morning with high temperatures slightly warmer than yesterday. Extreme Heat Warning goes into effect at 10 am and lasts through Sunday. Moisture on the limited side with PWATs in the 0.90" to 1.10" range with isolated spots up to 1.30" per GOES. Isolated to widely scattered thunderstorms this afternoon/evening with brief heavy rain and gusts up to 40 mph from the strongest storms. Forecast for today looks in great shape. && .KEY MESSAGES... -A low grade monsoon pattern into the weekend with just isolated showers and thunderstorms mainly from Sells eastward today and then south and east of Tucson Saturday with dry conditions areawide Sunday. Below normal monsoonal thunderstorm activity is expected next week. -Extreme heat is expected through the weekend with high temperatures 6 to 10 degrees above normal. Above normal temperatures continue next week with increasing likelihood of continued extreme heat, especially around next Wednesday and Thursday. && .DISCUSSION...After a somewhat more active day yesterday and last night, we`re transitioning right back into a low grade monsoon pattern today. The mid/upper level high will be settling back in over southern Arizona which is not a favorable position for storms due to subsidence aloft. However, there is still quite a bit of lower level moisture recycling underneath which will be enough for isolated showers and thunderstorms this afternoon into this evening. These storms won`t be particularly strong or well organized but can result in brief heavy rain and gusty winds. The activity will mainly be from Sells eastward with more of a focus on the higher terrain and a few storms over the valleys. As drier air continues to move in from the west on Saturday that will shunt isolated thunderstorms to locales mainly south and east of Tucson. With the high still over the area Sunday and lower to mid level flow becoming west to northwest, even drier air will overspread the region with any thunderstorms south of the Int`l border. An Extreme Heat Warning is in effect today through the weekend for much of the area with highs 6 to 10 degrees above normal. HeatRisk values are marginal today but will continue the heat headline as is for continuity. Next week is shaping up to be another hot week. Ensembles are in good agreement in briefly nudging a strengthening high aloft to our east early next week. This could open the door for a bit of a moisture push by Monday and Tuesday for low grade/slight chances of thunderstorm activity through midweek. The 500mb high will then nudge west to near the AZ/NM border and continue to strengthen, peaking Thursday with heights near 6000 meters. This is quite anomalous at 3 to 4 standard deviations above normal. It`s becoming increasingly likely later shifts will need to hoist more heat headlines especially mid to late next week. The main uncertainty for the time period between the heat this weekend and the heat mid to late next week is the potential for a bit of moisture early next week that could keep temperatures slightly lower than currently forecast. The current forecast high is 110 degrees in Tucson next Thursday. The all time high for August in Tucson is 112 degrees (1993) and locally used heights/thickness regressions indicate this could be in jeopardy next Thursday so we`ll be keeping a close eye on the trends with the mid/upper high placement and strength. && .AVIATION...Valid through 02/12Z. SKC-FEW clouds 10-15k ft AGL thru 01/18Z, then SCT clouds 8-12k ft AGL with isold -SHRA/-TSRA thru 02/03Z. Skies then clearing thereafter thru the end of the valid period. Winds generally below 12 kts away from thunderstorm activity, with occasional afternoon gusts to 20 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Isolated thunderstorms this afternoon into this evening, then drying this weekend with slight chances of showers and thunderstorms mainly south and east of Tucson Saturday with dry conditions areawide Sunday. Overall winds are expected to remain under 15 mph with occasional afternoon gustiness, however strong erratic winds are possible with any thunderstorm. Hot temperatures will continue into next week with a low grade monsoon pattern early next week. && .TWC WATCHES/WARNINGS/ADVISORIES... Extreme Heat Warning until 8 PM MST Sunday for AZZ501>507-509-515. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson