FXUS65 KTWC 091922 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 1222 PM MST Thu Jul 9 2026 .SYNOPSIS...Isolated to scattered showers and thunderstorms through Friday, with an increase in storm chances and coverage over the weekend through early next week. Hot temperatures today, lowering over the weekend into early next week. && .DISCUSSION...A flat ridge of high pressure will extend from the eastern Pacific across northern Baja and into western Arizona through Friday. Over the weekend, the ridge shifts northeast to north of the Four Corners. The ridge continues to move northeast early to mid next week when it will be centered over the high and central plains. By the following weekend, the upper high shifts westward back into the Four Corners region. With the upper high in close proximity, Heat continues to be a concern today, with high temperatures topping out 4-7 degrees above normal. An Extreme Heat Warning remains in effect through 8 pm MST this evening for much of Pima County, south-central and southeast Pinal County and the Gila River Valley of Graham County. For more information on this product, please refer to PHXNPWTWC. Blended total precipitable water satellite imagery shows PW values currently ranging from 0.80" in the White Mountains to 1.10"-1.25" along the International Border. PW values will remain relatively unchanged through Friday across the eastern half of the forecast area, while the models forecast a gulf surge to bring in higher PW's over the far western deserts. Isolated to scattered thunderstorm chances today and Friday will be roughly east of a line from Hannagan Meadow to Tucson to Nogales. The steering flow remains northeast to southwest at 10-15 mph. The main threats today will be gusty outflow winds to 45+ mph, blowing dust along Interstate 10 in Cochise County, as well as brief localized heavy rainfall with the strongest storms. The same threats exist on Friday, although wind gust potential diminishes slightly into the 40-45 mph range. This weekend into early next, the steering flow shifts to an east to west direction, as the upper high becomes centered north/northeast of the Four Corners. PW's are forecasted increase into the 1.25"- 1.50" range areawide and flash flooding will become a concern. Thunderstorm chances/coverage increase over the weekend to include all of southeast Arizona. In addition, the mid-level steering flow looks favorable for the potential for some clustering of storms and/or organized convection which could lead to an enhanced severe threat. The active pattern continues into early next week. WPC has a large portion of our forecast area highlighted for a Marginal Risk of Excessive Rainfall Saturday through Monday. High temperatures over the weekend will lower to right around normal, which is the lower 100s in the lower deserts from Tucson westward and in the Gila River Valley, with mid to upper 90s in the lower elevation locations of Santa Cruz and Cochise counties. By early next week, forecasted high temperatures will lower to 1-3 degrees below normal. By mid next week, PW's are forecasted to be in the 1.0"-1.25" range from Tucson eastward and in 1.25"-1.50" range across the lower deserts as the upper high shifts east into the central plains. This pattern will still result in a favorable monsoon flow across southeast Arizona, with the continuation of a daily chance for showers/thunderstorms, as well as a daily risk of isolated severe storms and/or flash flooding. Overall, a favorable monsoon flow has arrived and looks to be in place through at least the following weekend. There will be day to day variability in thunderstorm chances/coverage, along with typical monsoon hazards. && .AVIATION...Valid through 11/00Z. FEW-SCT (locally BKN) clouds at 8k-11k ft AGL and ISOLD-SCT -SHRA/ -TSRA. There is the potential for outflow winds up to 45 kts thru 10/04Z. Clouds and storms diminishing between 10/04Z and 10/17Z. Aft 10/19Z through the end of the forecast period, SCT-BKN clouds at 8k- 11k ft AGL and ISOLD-SCT -SHRA/-TSRA mainly east of KTUS. Outside of any thunderstorm outflows, SFC wind generally less than 12 kts, favoring a WLY/NWLY direction during the afternoon/early evening hours and variable in direction at other times. The exception will be in the Gila River Valley near KSAD aft 10/19Z thru the end of the valid period, where SFC wind will be 15-20 kts with gusts to 30 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Above normal high temperatures (4-7 degrees) today, with highs lowering to around normal over the upcoming weekend. Gusty northwest winds of 15-20 mph and gusts to around 30 mph in the Gila River Valley Friday afternoon/early evening. Min RH values in the lower elevations in the 13-20 percent range through Friday, increasing 5-10 percent by late in the weekend into early next week. Outside of any thunderstorm outflow winds, 20-foot winds will generally be less than 15 mph into early next week, except in the Gila River Valley on Friday. There will be a daily chance of showers and thunderstorms mainly during the afternoon/evening hours through Friday. Increasing thunderstorm chances and coverage are expected over the weekend through early next week. && .TWC WATCHES/WARNINGS/ADVISORIES... Extreme Heat Warning until 8 PM MST this evening for AZZ501- 502-504>506-509. && $$ Zell Visit us on Facebook, X, YouTube, and at weather.gov/Tucson