Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
889 FXUS65 KTWC 151553 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 853 AM MST Tue Jul 15 2025 .SYNOPSIS... Potentially active day today, especially from Tucson southward. Latest HiRes models continue to show development starting around noon triggering off the White Mountains and then south of Tucson. Main threats today will likely be heavy rainfall. Have a plan! && .KEY MESSAGES... - An average to above average grade monsoon day is forecast for today. Heavy rain and the potential for flash flooding is the primary threat, mainly for eastern Pima (including Tucson), Santa Cruz, and Cochise Counties. - Monsoon activity Wednesday and Thursday will likely depend on what happens the previous day. Uncertainty in the forecast overall is high. - Temperatures will generally be within a few degrees of normal, with low to moderate HeatRisk. && .PREV DISCUSSION... /issued 232 AM MST Tue Jul 15 2025/ .SYNOPSIS... Temperatures will be within a few degrees of normal for the next week. Today will be a more active monsoon day, then typical day to day variability thereafter through the rest of the week. Showers and thunderstorm with the potential for heavy rainfall will be present, especially from Tucson to the south and southeast today and Wednesday. && .KEY MESSAGES... - An average to above average grade monsoon day is forecast for today. Heavy rain and the potential for flash flooding is the primary threat, mainly for eastern Pima (including Tucson), Santa Cruz, and Cochise Counties. - Monsoon activity Wednesday and Thursday will likely depend on what happens the previous day. Uncertainty in the forecast overall is high. - Temperatures will generally be within a few degrees of normal, with low to moderate HeatRisk. && .DISCUSSION... Overnight satellite imagery shows that we are currently in a Type II monsoon configuration, with upper level high centered over southern Nevada and northeast flow aloft over our forecast area. While normally this would be a favorable pattern for thunderstorms over forecast area, the best dynamics and instability stayed to our south yesterday. There is still scattered residual cloud cover from the showers that were able to develop yesterday. A more active pattern is still shaping up for today as the upper high shifts back toward the Four Corners region...a Type I monsoon configuration. Flow should be much weaker today than yesterday, which would suggest that any storms that develop will be slow moving. With abundant moisture, the primary threat today will likely be heavy rain that could lead to flash flooding. The HREF is generally in agreement that storms today should be starting up during the early afternoon, with some potential for thunderstorms continuing into the overnight hours. The best potential for flash flooding should be over eastern Pima, Santa Cruz, and Cochise Counties. A Flash Flood Watch has been issued for these locations. HREF is showing a roughly 20 percent chance of exceeding 2" of rain with the most intense of these storms. Forecasts for Wednesday and Thursday will likely be tricky this far out, as the weather will depend on what happens the previous day. At this stage, the forecast reflects average grade monsoon days, but with a high degree of uncertainty. A drier period is likely to set in at some point in the next week, but it is highly uncertain when this will be. This is because there is low predictability in the evolution of a closed upper low off the Baja coast over the next several days. There will be some day to day variability in high temperatures over the next week, but generally expect them to be within a few degrees of normal for this time of year. && .AVIATION...Valid through 16/12Z. SCT-BKN 7-12k ft AGL through the period. Another round of SCT TSRA/SHRA is expected aft 15/19Z for much of southeast Arizona. Wind gusts of 40-50 kts with 1-3SM VSBY in BLDU are possible with the thunderstorms today, especially near KSAD. Otherwise, SFC winds mainly less than 10 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... A more active monsoon pattern this week. Deeper atmospheric moisture moving into the will increase the potential for heavy rainfall and localized flash flooding, especially today. Temperatures will remain above normal through today, then drop back down to near or slightly below normal by mid week. Winds will remain westerly from 10-15 mph, with occasional gusts at or above 25 mph. Afternoon RH values in the low lying areas will be between 10-15% this afternoon, then 20-30% through the remainder of the week. && && .TWC WATCHES/WARNINGS/ADVISORIES... Flood Watch from noon MST today through this evening for AZZ502>504-507-508-512>515. && $$ Public...Singer Aviation...Singer Fire Weather....Singer Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson