Forecast Discussion
294 FXUS65 KTWC 091951 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 1252 PM MST Fri Oct 9 2026 .SYNOPSIS... Temperatures will lower to near normal Saturday and then below normal through most of next week. Slight chances for precipitation mainly from southern Pinal County southward to the Int`l border this afternoon. Thereafter, expect a longer duration period of precipitation chances for our area Saturday through Tuesday. Gusty winds are also expected, especially Sunday and Monday. && .DISCUSSION...Mostly sunny to partly cloudy skies this afternoon across southeast Arizona with surface dewpoints in the 50s and precipitable water values ranging from about 0.7 to 1 inch across the region. There is just enough moisture for some cloud build-ups this afternoon and isolated showers and thunderstorms mainly from southern Pinal county extending southward through the Tucson Metro and down through Santa Cruz County to the Int`l border. These storms don`t look particularly impactful but some gusty winds up to 40 mph can occur with storm activity today. These storms will tend to diminish after sunset this evening. This weekend is looking particularly active as troughing off the California coast results in recurvature of Tropical Storm Rachel today with rapid movement to the northeast and expected landfall as a Tropical Storm across far northern Baja late Saturday night or early Sunday morning. The impacts from this system are now pretty well baked in across our area for the weekend. On Saturday, increased moisture will help result in scattered showers and thunderstorms especially Saturday afternoon and evening. A few of these storms could be strong to locally severe with wind gusts of 40 to 60 mph and produce locally heavy rain along with small hail. The greatest uncertainty for Saturday remains how unstable the airmass becomes which will determine the intensity of the thunderstorms. Any stronger thunderstorms that develop could drop a quick half inch to inch of rain or so with an isolated flash flood threat. Meanwhile, as Rachel skirts by to our west, there is a non-zero tornado threat as early as Saturday afternoon but especially Saturday night into early Sunday mainly across western Pima County as shear and helicity parameters are more favorable for these locales. The SPC has placed locales from Tucson westward in a marginal risk severe thunderstorms for Day 2 (12Z Sat to 12Z Sun) with a 2% tornado risk for western Pima County. The combination of Rachel swinging through to our west Saturday night and the troughing aloft will result in breezy to windy conditions for most of southeast Arizona on Sunday. Expect south to southwest winds of 25 to 35 mph from Tucson westward and gusts of 45 to 55 mph with winds a bit lower east of Tucson. Any convective activity will also result in the potential for stronger winds being mixed down. Wind Advisories have been hoisted from Tucson westward on Sunday. As Rachel swings north, our area will remain in southerly flow with scattered thunderstorms once again on Sunday. Total rain amounts this weekend will generally be in the 0.25" to 0.75" range from Tucson westward and 0.10" to 0.25" range east of Tucson with up to 1 to 2 inches in the mountains and within locales that happen to see a couple of rounds of stronger thunderstorms. It should be noted that precipitation for this event will be more variable and while these are areal averages, some locales could conceivably end up with little rainfall when all is said and done. Southerly flow continues on Monday ahead of the longwave trough with breezy winds continuing. While moisture levels back off on Monday (PWAT 0.75" to 1 inch), the combination of this moisture and increased lift and forcing ahead of the trough will result in isolated to low end scattered showers and thunderstorms. Certainly not looking as widespread as the weekend but rain chances continue nonetheless. We`ll still have the upper low to our north on Tuesday as well for potential for a few lingering showers. By Wednesday, drying has moved back into our area and with dry conditions through the remainder of the work week. Temperatures will drop to near normal temperatures on Saturday, then an extended period of below normal temperatures will occur Sunday through the middle of next week. && .AVIATION...Valid thru 11/00Z. SCT-BKN clouds 9-12k ft AGL with ISO -SHRA/-TSRA develops mainly from KTUS southward thru about 10/03Z. Renewed development of SCT SHRA/TSRA is expected for much of the area aft 10/19Z through end of valid pd. Gusty winds to 35 kts possible around convection. SFC winds E/SE around 8-15 kts with gusts to 20kts this afternoon. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...The combination of a low pressure system and the remnants of Tropical Storm Rachel will bring breezy to windy southwest winds Sunday and Monday with wind gusts of 35 to 45+ mph on Sunday for much of southeast Arizona. Highest wind potential will be from central Pima County west. Breezy winds continue on Monday as well with winds 15 to 25 mph with gusts around 35 mph. This weather system will bring a 30-70 percent chance for rain Saturday and Sunday, lowering to 20 to 50 percent Monday and Tuesday. Minimum relative humidity values will remain 15-30 percent in lower elevations and above 40 percent in high elevation terrain through Saturday. && .TWC WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 2 AM to 11 PM MST Sunday for AZZ501-502-505. Wind Advisory from 7 AM to 11 PM MST Sunday for AZZ503-504-506-514- 515. && $$ Visit us on Facebook, X, YouTube, and at weather.gov/Tucson
NWS TWC Office Area Forecast Discussion