Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
115 FXUS65 KTWC 100309 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 809 PM MST Wed Jul 9 2025 .SYNOPSIS... Hottest day of the forecast period is on tap for today for much of the forecast area, with isolated thunderstorms possible mainly east and south of Tucson for the rest of the week. && .KEY MESSAGES... - Extreme Heat Warning in effect until 8 PM MST July 9th. Major to Extreme HeatRisk. - "Low-grade" monsoon pattern for the next several days. Storms and showers that develop will generally be east and south of Tucson. - Decreasing temperature trend beginning tomorrow for the next 7 to 10 days. Near normal temperatures by early next week. Minor to localized Moderate HeatRisk. - Monsoon pattern ramps up again early next week. && .UPDATE... With temperatures gradually cooling this evening, the Extreme Heat Warning was allowed to expire as planned. Temperatures overnight will remain above normal, with hot temperatures again tomorrow. Though overall highs will mostly be slightly below today`s, HeatRisk still remains in the moderate to major range with highs around 5 to 8 degrees above normal. && .PREV DISCUSSION... /issued 216 PM MST Wed Jul 9 2025/ Cumulus clouds are starting to build up over the higher terrain. The center of high pressure overhead has situated over central to southern Arizona increasing temperatures leading to an Extreme Heat Warning. The warning is in effect until 2000 MST for portions of Pima, Pinal, southern Graham and Greenlee counties. Expect dangerously hot temperatures around 108 to 112 degrees with widespread Major HeatRisk and localized Extreme HeatRisk in Graham county. Major HeatRisk means that anyone without effective cooling or adequate hydration will be impacted by the heat. The high pressure center has shifted ever so slightly to the southwest from this morning leading to north to northwest mid- level winds over much of the area which is typically not a favorable wind alignment for thunderstorm development. East and south of Tucson there is a better wind alignment- more from the north to northeast, greater instability- around 1000 J/kg of CAPE and moisture- PWATs around 1.0 to 1.2 inches therefore there is a slight chance (15 to 30 percent) for storms and thunderstorms this afternoon. The main concern associated with storms is gusty outflows, dust, and localized heavy rainfall they may lead to flash flooding. Tomorrow, conditions will be less favorable for thunderstorms than today. Moisture will recede southward into Mexico and the mid-level winds will be from the northwest across southern Arizona. The greatest chance for storms and showers will be along the Arizona/ Mexico international border. The high pressure will continue on its westward track centering over northern Baja by Friday morning. The shift in high pressure to the west will persist for the next several days leading to a gradual trend in decreasing temperatures. By early next week, temperatures will be near normal and HeatRisk will be Minor with localized Moderate. Early next week, high pressure will begin to build in the Four Corners area setting up for an uptick in more widespread thunderstorm activity. More to come as we get closer. && .AVIATION... Valid until 11/00Z. SFC winds will generally be from the northwest at 5 to 10 knots shifting to the southwest overnight. FEW to SCT clouds AOA 10 to 15k ft AGL are developing over the Sky Islands from KTUS east and south. Clouds will continue to develop this afternoon to SCT to BKN AOA 9 to 13k ft. Chance for showers and storms to develop mainly east and south of KTUS this afternoon into the early evening. Expect gusty and erratic outflows with short term, locally reduced visibility under or near thunderstorms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Isolated to low-end scattered thunderstorm coverage is expected to the south and east of Tucson into the weekend. The main threat for storms will be the potential for strong gusty and erratic outflow winds 40-45 mph. Otherwise, an eventual uptick in monsoon activity is possible later this weekend and into next week as the upper high shifts to a more favorable location aloft. Temperatures will remain above normal this week with hottest temperatures Today. By early next week temperatures will be near normal. Winds generally light and under 15 mph with the exception of stronger winds in the Gila River Valley Thursday and Friday afternoon with northwest sustained winds around 15 to 20 MPH gusts to 30 MPH. && && && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...Edwards Public...Malarkey Aviation...Malarkey Fire Weather....Malarkey Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson