Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
660 FXUS65 KTWC 102038 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 138 PM MST Mon Nov 10 2025 .SYNOPSIS...High temperatures today will remain above normal from Tucson to Nogales westward, and near normal to the east. Below freezing morning lows are possible in valleys east of Tucson including the Sulphur Springs Valley. A low pressure system will likely impact the region Friday through the next weekend, bringing chances for rain and high elevation mountain snow, cooler temperatures, and windy conditions. && .DISCUSSION...Breezy easterly winds will slowly diminish this afternoon as the surface pressure gradient weakens. Aloft a ridge is positioned over the Southwest and Great Basin with a strong low over the eastern U.S. This ridging will stay in place through the middle of the week but flattens out some as the low moves into the Atlantic and the upper level pattern becomes less amplified. As a result high temperatures will remain 4-7 degrees above normal through Thursday. Tonight, thanks in part to lighter winds, low temperatures will be at or a few degrees below freezing for the Sulphur Springs Valley and Benson/St. David area. The Freeze Watch has been upgraded to a Freeze Warning for these areas. Starting Thursday a Pacific low, currently in the Gulf of Alaska, begins to move onshore. Ensembles bring it through the Southwest Friday into Saturday as a closed low, still some uncertainty on the exact timing. Models are also bringing the low further south than previous runs with the Euro the furthest south. The Euro is also the slowest with the low`s evolution and brings it through Sonora while the GEFS shows the low moving through southern Arizona. Even with the lower confidence in the low`s track there is high confidence that it will bring precip chances starting Friday morning continuing into Saturday, cooler temperatures, and breezy winds. Initially precip looks to be all rain, then sometime late Friday into Saturday morning begins to change to snow at mountain tops. Rain totals in the valleys for Friday and Saturday range from 0.01-0.5 inches and 1.0+ in the mountains. Snow totals right now look to be below advisory levels, although they have been trending up in the White Mountains with almost each model run. High temperatures will be around normal to a few degrees below normal Friday then cool 10-15 degrees below normal Saturday and Sunday. Areas easy of Tucson could also see freezing morning temperatures Sunday and Monday. && .AVIATION...Valid through 12/00Z. SKC through the day, then cirrus above 20k feet arriving from the west after 11/06Z. East to southeast surface winds 10-15 kts with gusts to 25 kts through 10/22Z, then gradually diminishing through the evening. Tuesday afternoon winds resume their normal diurnal pattern becoming west northwest 5-10 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...East/southeast winds of 12-18 mph with gusts to 25 mph this afternoon, then gradually diminishing late this afternoon and evening. Light winds expected Tuesday and Wednesday with minimum relative humidities of 12 to 22 percent. A low pressure system is expected to impact the region late in the work week through the weekend, with increasing confidence in the system arriving on Friday. Windy conditions, cooler temperatures, and chances for rain and high elevation mountain snow are expected to arrive with this system. && .TWC WATCHES/WARNINGS/ADVISORIES... Freeze Warning from 2 AM to 9 AM MST Tuesday for AZZ507>509. && $$ Hardin Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson