Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
194 FXUS65 KTWC 182019 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 119 PM MST Sat Oct 18 2025 .SYNOPSIS...One more afternoon of below normal temperatures then temperatures warm to normal to a few degrees above normal tomorrow into the middle of next week. Dry conditions will also prevail through Tuesday with a slight chance of rain for mountain areas east of Tucson Wednesday. && .DISCUSSION...This afternoon southeast Arizona was situated between a weak closed upper low off the coast of California and Baja California and a ridge of high pressure building over central Mexico. Few to scattered high clouds expected this afternoon with high temperatures running below normal by around 4 to 8 degrees. As the ridge of high pressure continues to build, expect temperatures to rise above normal into the upper 80s to around 90 degrees tomorrow resulting in minor HeatRisk to return for valley locations. Current NBM probabilities for 90 degrees or greater in Tucson are 10 percent Sunday and Monday, 60 percent on Tuesday, 50 percent Wednesday, and decreasing to 5 percent Thursday. Otherwise, little to no weather related impacts expected this weekend. The next potential for minor/nuisance impacts will be Wednesday as the aforementioned upper low opens into a trof and passes over central Arizona. A modest increase in mid-level moisture and forcing for ascent aided by terrain will bring scattered to broken clouds Tuesday through Thursday and slight chances (10-25%) for showers mainly in the White Mountains, Chiricahua Mountains, and Sky Islands Wednesday. Not much in the way of measurable rainfall is currently anticipated with NBM QPF remaining under 0.05". Locally breezy/gusty winds are possible with the passage of this system primarily for wind prone valley locations Wednesday afternoon. Only localized minor/nuisance impacts are currently expected as NBM probabilities for gusts over 25 mph are low (10-30%). The trof will exit the area Thursday leaving slightly cooler temperatures in its wake. Looking ahead at the extended forecast, the Climate Prediction Center (CPC) depicts temperatures to lean above normal and precipitation to be below normal for southeast Arizona. Ensembles currently agree that positive height anomalies will be in place through the last week of October with a ridge of high pressure building and remaining in place over the Desert Southwest. This solution would support continued warm and dry conditions to close out October. && .AVIATION...Valid through 20/12/00Z. FEW-SCT clouds AOA 20k ft AGL. SFC winds WLY/NWLY at 6-9 kts through 19/03Z and again after 19/20Z. Otherwise, SFC winds light and VRBL. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Minimum RH values will be in the 15-25 percent range in the valleys into next week. 20-foot winds mainly 15 mph or less, with occasional gusts to 20-25 mph. Chance for breezy winds Wednesday as a weather system moves through. High temperatures will be below normal this afternoon, warming to normal or just above normal levels tomorrow into next week. Expect dry conditions over the next 7 days with the exception of the White Mountains Wednesday, which will see a 20 percent chance for showers. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ DVS Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson