Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
342 FXUS65 KTWC 101012 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 312 AM 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... Southeastern Arizona sits between deep cyclonic flow to the east and an upper level ridge centered over southern California towards the Great Basin this morning. The trough to the east has slid a backdoor cold front through areas east of Tucson over the previous 18 hours or so with an associated modest pressure gradient bringing breezy winds to the area this morning. High temperatures today will again range from around 4-7 degrees above normal from Tucson west, to closer to normal in areas to the east. By Tuesday morning the pressure gradient should have weakened, allowing for lighter winds and better radiational cooling. This should bring morning lows down below freezing in colder eastern valleys including the Sulphur Springs Valley and through St. David and Benson. A Freeze Watch remains in place for these locations. A notable pattern change looks likely by the end of the work week as western ridging gives way to a deep trough passage Friday through the weekend. Recent global ensemble runs have been converging on timing with an increasing signal leaning towards Friday for the trough axis arrival. There are still some differences in timing from early to late Friday, while a small subset of members feature a far less progressive solution and delay the system until very late Friday to Saturday. Overall the likelihood of a pattern shift is high, so the message continues to be to expect a significant cool down by the weekend, chances for rain and high elevation mountain snow, and windy conditions. && .AVIATION... 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 10/23Z, then gradually diminishing through the evening. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... East/southeast winds of 10-20 mph with gusts to 30 mph continue today, though will gradually diminish 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 Watch from late tonight through Tuesday morning for AZZ507>509. && $$ Public...Edwards Aviation...Edwards Fire Weather....Edwards Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson