Forecast Discussion
487 FXUS65 KTWC 082100 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 200 PM MST Thu Jan 8 2026 .SYNOPSIS...A winter weather system will move across Southeast Arizona today resulting in valley rain and mountain snow showers with embedded thunderstorms this afternoon to evening. Cold air associated with this system will usher in unseasonably cool to cold temperatures to the area, with freezing morning low temperatures possible across the region Friday and Saturday mornings. && .KEY MESSAGES... The second winter weather system will impact Southeast Arizona today, with a strong cold front moving from the northwest to the southeast this afternoon into this evening. 1. Winter Weather Advisories: A Winter Weather Advisory remains in effect for the mountainous areas including the White Mountains, Galiuro, Pinaleno, Catalina, and Rincon Mountains through 11 PM MST this evening. 2. Mountain Snow Accumulations: Although snowfall will occur this morning in between the two winter storm systems, the heavier snowfall will occur during the afternoon and early evening hours. Snow levels will start off between 6500-7000 feet this morning, lowering to 6000 feet this afternoon, then rapidly lowering to 4500-5000 feet this evening. This system is colder and will be more efficient in producing snowfall. Expect an additional 4 to 8 inches of snowfall above 6000 feet with locally higher amounts on the peaks. 3. Valley Rainfall: Widespread rain showers for the valleys of Southeast Arizona this afternoon and this evening. The heaviest (moderate-intensity) rainfall will along the cold front passage late this afternoon into the early evening, especially near thunderstorms. Rainfall amounts today will be less than what we experienced Wednesday across the area...generally between 0.10 and 0.40 inches. Given the saturated soils from the rainfall Wednesday, this rainfall runoff may still result in significant ponding of water in normally dry washes, roadway dips and other low-lying areas. 4. Strong and Gusty Winds: A strong cold front moving from the northwest toward the southeast this afternoon into this evening will result in breezy southwest to west winds 15 to 25 mph with gusts between 35-40 mph. 5. Freezing Temperatures: Very cold to freezing temperatures are expected both Friday and Saturday morning for the valleys from Tucson east. Potential for icy roads Thursday night to Friday morning. Freeze Warning is in effect for Friday and Saturday mornings. && .DISCUSSION...Southeast Arizona has enjoyed a break in the weather this morning. Yesterday brought a wet day across the region with mountain snow on the Sky Islands. This break will be coming to the end very soon. A cold front is located northwest corner of Arizona and it will be moving southeast through the rest of the day. Radar currently indicates rain showers and a few lighting strikes in Pinal county. The front will be moving through the region and impacting Tucson as early as 3pm with Safford experiencing impacts within an hour of this writing, and Benson by 5 pm. Models show the front being robust between 3pm and 6pm with strong gusty winds of 30-35 mph with embedded thunderstorms. Thunderstorms will be able to produce stronger gusts, small hail is possible, and locally heavier rainfall. Generally, rainfall totals through tonight will be 0.1-0.4 inches with locally higher amounts due thunderstorms. Plus, mountain snow accumulation will continue to add 4-8 inches of snow on the mountains. Winter Weather Advisories are still in effect through 11 pm tonight. The front will become more diffuse and losing some key ingredients to sustain thunderstorms. The front will still bring gusty winds through the remaining areas as it travels southeast. Light-to- moderate rain will continue as well. The front will also bring snow levels down to 4500-5000 feet in the eastern counties. This may bring low chances for snow showers to slightly mixed reaching the valley floors in Graham, Greenlee, and Cochise counties. Low forecaster confidence on this occuring but a non- zero chance. The next big picture after the cold front will be the cold to freezing temperatures. Temperatures will drop to unseasonable with chances of hitting 32 degrees being 60% in Tucson, 55% in Nogales, 35% in Eloy, and 60%+ in the eastern counties on Friday. probabilities expand and increase on Saturday as the cold air settles more in the region. Eastern counties can experience temperatures in the lower 20s to upper teens. There may be areas not decoupling fully, and lingering fog or low clouds that would keep temperatures elevated above freezing. Yet, models show high probabilities for these cold-freezing temperatures. Saturday morning will be the one of the coldest days of this year. Therefore, Freeze Warning and Hard Freeze Warnings are in effect for most of Southeast Arizona on Friday and Saturday. Late this weekend, temperatures will slowly moderate and warm up. A tight pressure gradient will form by Saturday, resulting in breezy to gusty east to southeast winds. The strongest winds will be on Sunday. Stay tune for the latest updates! && .AVIATION...Valid through 10/00Z. SCT-BKN 4-8k ft AGL BKN-OVC 8-10k ft AGL with isolated to scattered valley -SHRA and mountain -SHSN through 08/20Z, increasing in coverage to numerous as a cold front sweeps through Southeast from the northwest to the southeast between 08/20Z and 09/06Z. CIGS 2-5k ft AGL during the late afternoon and early evening with mtn obscurations possible. A few embedded -TSRA will be possible near the cold front. Clouds and ceilings will lift becoming FEW-SCT 6-12k ft AGL. SFC winds SLY/SWLY 18-22 kts with gusts to 30-35 kts with the passage of the cold front this afternoon and evening. After the frontal passage, winds NWLY at 10-15kts with gusts to 30 kts until 09/06Z. Then SFC winds less than 10 kts through the overnight period. By 09/18Z, SFC winds NWLY at 10-12 kts with gusts up to 20 kts through the end of the period. Aviation discussion not updated for TAF Amendments. && .FIRE WEATHER...A winter weather system will move across Southeast Arizona today resulting in another round of valley rain and mountain snow showers with embedded thunderstorms. The best chance for storms will occur with the passage of a cold front moving from the northwest to the southeast during the afternoon into the evening. Breezy 20-foot winds from the southwest to west 15-20 mph with gusts to 35-40 mph will be possible along the cold front. This system will be more efficient at producing accumulating mountain snowfall than the first system. A Winter Weather Advisory remains in effect for the White Mountains, Catalina and Pinaleno Mountains through 11 PM MST this evening. This second system will also usher in unseasonably cool morning low temperatures to the area, with freezing temperatures across the valleys from Tucson east Friday and Saturday mornings. Minimum RHs today will be between 50-60 pct in the valleys and 75-90 pct in the mounatins, lowering to 25-35 pct in the valleys and 35-45 pct in the mountains Friday into early next week. Gusty east to southeast winds will develop late Saturday and Sunday. Temperatures will moderate as well this weekend to the new week. && .TWC WATCHES/WARNINGS/ADVISORIES... Freeze Warning from midnight tonight to 9 AM MST Saturday for AZZ502>509. Winter Weather Advisory until 11 PM MST this evening for AZZ510- 511-514. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
NWS TWC Office Area Forecast Discussion