Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
097 FXUS65 KTWC 131010 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 310 AM MST Thu Nov 13 2025 .SYNOPSIS... High temperatures will remain 5 to 10 degrees above normal through Friday. A low pressure system is then expected to impact the region this weekend, bringing chances for showers, cooler temperatures, and breezy conditions. Unsettled conditions are expected to continue next week along with below normal temperatures. && .DISCUSSION... Water vapor imagery this morning depicts a deep, closing low off the west coast, with a stream of high level moisture through southwest flow from the base of the trough through the desert southwest. With southeastern Arizona still sitting under a ridge downstream from this eastern Pacific trough, warm daytime temperatures with periods of high level clouds will remain the story into the weekend. The Pacific low and its eventual west coast crossing has been a problem for models to handle this week in regards to timing, depth, and progression across the region. Closed lows tend to make their entrance far slower than models indicate and this one has been no exception. The model run to run trend over the past 24-48 hours has seen the trough`s advertised arrival delay from Friday to now late Saturday to Sunday. GFS/ECWMF/CMC ensembles do depict non- zero chances of earlier Saturday precipitation, mainly in western Pima. However given the pattern a later arrival seems more reasonable. The temperature trend will follow the eventual timing of this trough, with unseasonably warm temperatures now looking likely through Saturday, then cooler Sunday. As for precipitation totals, it`s looking increasingly likely that stronger upper level dynamics will be kept further north through central to northern Arizona, keeping southeastern Arizona out of the threat for heavier rainfall rainfall rates. The overall spread of rain amounts range from a few hundredths of an inch to around a half inch on the high end through the end of the weekend. With the northern track of this low, accumulating mountain snow is less likely with snow levels above 9000 feet. Next week still looks to be active as ensemble mean heights show a series of troughs moving through the southwest region. The 6-10 day CPC outlook subsequently advertises likely chances for above normal precipitation and below normal temperatures. && .AVIATION... SCT-BKN cirrus AOA 20k feet through much of the forecast period. Surface winds light, terrain driven, and under 10 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Warm and dry through Friday with light terrain driven winds under 12 mph. A low pressure system will cross the region this weekend and bring cooler temperatures, increased winds, and chances for showers. Shower chances may arrive as early as early Saturday for areas west of Tucson, but greater chances should be delayed until late Saturday and Sunday. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Public...Edwards Aviation...Edwards Fire Weather....Edwards Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson