Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
607 FXUS65 KTWC 091049 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 349 AM 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. && .DISCUSSION... The primary story for today will be the heat, which will bring widespread Major HeatRisk over much of southern Arizona during the day today. The SW US remains under the influence of a strong high pressure system aloft, which has continued to build the past few days. Building heights will reach their apex today. Thus, an Extreme Heat Warning is in effect from 10am this morning through 8pm this evening. A few locales may approach their daily records today. Get an early start on outdoor activities, make sure to remain well hydrated and check on friends and neighbors today. Along with the heat today, we can expect to see some brief light breezes which will only act to enhance the furnace like conditions. We`ve been advertising this pattern as "low grade monsoon" in nature, and today and tomorrow will be no exception. While widespread activity is not expected, isolated thunderstorms with gusty and erratic winds are possible, especially in areas south and east of Tucson the next few afternoons/evenings. PW values from previous soundings have consistently been >1.25 inches, thus a brief heavy downpour isn`t out of the question. Stronger downdraft activity could also kick up some dust across portions of eastern Pima and Cochise Counties. Past Thursday and into the weekend the flow pattern at upper levels will likely not support widespread monsoonal activity, with limited moisture available. However, beyond the weekend and into next week there are hints that a more favorable monsoon pattern will present itself, and storm chances will increase. There should be a slight respite for the overpowering day time high temperatures after Thursday, but most locations will remain in the low 100s into next week. && .AVIATION... Surface winds will generally be westerly in nature between 8-13 knots at all terminals thru the forecast period. SCT-BKN clouds from 7-12k feet AGL will be possible at KTUS, KOLS and KDUG through the evening hours. Gusty and erratic outflows with more cloud cover are possible with any isolated thunderstorm activity near all terminals. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Isolated to low-end scattered thunderstorm coverage is expected to the south and southeast 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 Wednesday. Winds generally light and under 15 mph with the exception of gusty and erratic winds up to 35- 45 mph near any thunderstorms. && .TWC WATCHES/WARNINGS/ADVISORIES... Extreme Heat Warning from 10 AM this morning to 8 PM MST this evening for AZZ501-502-504>506-509. && $$ Public...Singer Aviation...Singer Fire Weather....Singer Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson