Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
248 FXUS65 KTWC 191942 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 1242 PM MST Sun Jul 19 2026 .SYNOPSIS... Rain showers and a few thunderstorms from Tucson west into the lower desert this afternoon, with more widespread shower and storm activity south and east of Tucson. An uptick in activity is likely into the first half of the week. Daytime temperatures remain below average by several degrees into midweek. && .DISCUSSION... Showers and thunderstorms continue to develop over the higher terrain of SEAZ, the Mogollon Rim, and higher elevations in NM. This activity will push into the lower deserts/valley locales by late afternoon and into the evening. The main threats will be heavy rainfall and gusty winds. While organized and more widespread severe weather is not expected, we cannot rule out an isolated 50kt gust. However, most wind gusts should remain below 40kts. As for flash flooding, the threat remains where storms are slow to move or any cell mergers. In addition, any area that has received heavy rainfall over the past several days will be quite susceptible. As for the Tucson Metro, confidence remains low for any activity today. Convection off the rim and to the east will try and push W/SW, but will run into increasingly stable conditions, especially as the sun goes down. We still cannot rule it out, but the best chance will be for the Catalina Foothills, Tanque Verde over to the far east side and south of the metro. Same threat of heavy rainfall and gusty winds with any activity in the metro. As we move into early week, better forcing moves in from the E/SE. A weak upper level low moves across AZ, which should help increase storm coverage for areas south and east on Monday. There should be westward expansion into the Tucson metro and central Pima Co by Tuesday, but confidence is only moderate on how far west activity gets. The main threats with the early week activity will be heavy rain, localized flash flooding, and gusty winds. There is a Marginal to Slight Risk for Excessive rainfall for much of SEAZ Mon/Tue, but confidence is too low at this time for a Flash Flood Watch. It will be more dependent on how the activity evolves today and better resolve in the higher res CAMs as we move into Mon/Tue. By mid week, the mid and upper level pattern shifts with a more E/SE flow. Flow will also increase with the potential for a weak easterly wave to move across AZ. This will keep daily isolated to scattered showers and storms through the rest of the work week. As flow increases, stronger storms with an increasing threat for strong gusty winds are possible. Temperatures remain several degrees below average through mid week, before warming to near/a few degrees above average. && .AVIATION /19Z SUNDAY THROUGH 19Z MONDAY/... Majority of the region went from BKN/OVC this morning to FEW/SCT AOA 6-8k ft agl this aftn. Iso/sct showers/storms developing over the higher terrain and will move into the lower deserts by later afternoon. KOLS/KDUG has the greatest chance for showers/storms with brief MVFR in storms. Otherwise, VFR with winds less than 12kts with the exception of gusts to 35-40kts in storms. KTUS on the fringe of activity today, but could still see VCTS/VCHS. VCTS/VCHS and the occasional shower could linger into the evening and overnight, but VFR will prevail. More shower and storm activity tomorrow. && .FIRE WEATHER... Daily chances for thunderstorms will continue each afternoon and evening through the next 7 days with day to day variability. An increase in thunderstorm activity is expected east of Tucson today, then expand in coverage the first half of the week. Minimum relative humidity 25-30 percent in the lower desert locations and above 40 percent in the mountains this week. Winds this week will remain mainly light and under 15 mph, though strong and erratic winds will be possible with any thunderstorm. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ SYNOPSIS... DISCUSSION...Michael AVIATION...Michael FIRE WEATHER...Michael Visit us on Facebook, X, YouTube, and at weather.gov/Tucson