Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
462 FXUS65 KTWC 030824 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 124 AM MST Wed Dec 3 2025 .SYNOPSIS...A weather system moving through the region today will result in cooler temperatures and breezy conditions, especially to the south and southeast of Tucson. Moisture moving out ahead of the cold front will result in isolated light rain showers (just enough rain to wet the ground) late this afternoon into this evening. Otherwise, dry weather returns to Southeast Arizona Thursday into next week with high temperatures returning to above seasonable levels next week. && .DISCUSSION...The upper pattern this morning is defined by a trough of low pressure moving south through the Great Basin, an upper ridge centered near 36N/140W with a neutral ridge axis extending north along 140W and a cutoff low west of the Baja near 23.5N/126.0W. As the upper ridge begins to flop into the Pacific Northwest and become positively tilted, we will see the upper trough in the Great Basin amplify and move a bit farther west than previously progged into NW Arizona by 03/18Z this afternoon, then east into northern NM by 04/06Z tonight. The southern periphery of this feature and associated surface frontal boundary will drag east through Southeast Arizona this afternoon into this evening. Expect breezy southwest to west winds develop out ahead of the main frontal boundary, especially southeast of Tucson where we will see SW-W winds 15 to 25 mph with gusts to 30-35 mph. The stronger flow associated with the more amplified/westerly track of the upper trough will advect moisture from the northern Gulf of California across the central and southern portions of the CWA late this afternoon into this evening. This moisture will then be lifted with the frontal passage resulting in isolated light rain showers and high elevation snow showers. Precipitation amounts (QPF) will be light, ranging from a trace to a few hundredths with less than an inch of snow above 8000 feet. Localized QPF amounts between a tenth to quarter inch will be possible on the WSW facing slopes of the higher terrain due to orographic influences. In any event, this precipitation will not be impactful...but will be evident with the frontal passage late this afternoon/this evening. Although the upper low itself moves out of the region Thursday, Southeast Arizona will remain in the mean trough across the Desert Southwest. This will result in slightly below normal afternoon temperatures the next few days with cool/chilly morning lows. Temperatures will then rebound and become more mild as we move through the weekend into next week as the upper ridge amplifies and becomes more dominant to our west. && .AVIATION...Valid through 04/12Z. FEW-SCT clouds 5-8 kft AGL through 03/17Z, then SCT-BKN clouds AOA 5 kft AGL increasing along a cold-front west of KTUS through the early afternoon, then spreading to areas east of KTUS in the late afternoon and evening. ISOLD -SHRA will be possible between 03/22Z and 04/06Z along and near this cold-front. SFC wind variable in direction and less than 12 kts through 03/17Z this morning, then SWLY/WLY at 12-18 kts with gusts to 25-30 kts this afternoon. The strongest winds will be to the south and southeast of Tucson along the International Border. This includes KOLS and the eastern valleys including KDUG. Winds will taper off after 04/03Z this evening thru the end of the period. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...A weather system moving through the region today will result in cooler temperatures and breezy conditions, especially to the south and southeast of Tucson. Moisture moving out ahead of the cold front will result in isolated light rain showers (just enough rain to wet the ground) late this afternoon into this evening. Expect elevated 20-foot winds from the west/southwest around 15-20 mph with gusts 30-35 mph over portions of eastern Santa Cruz and Cochise counties this afternoon and early this evening. Otherwise, Min RH values will be in the 25-35 percent range through Friday, lowering to 20-30 percent this weekend. Dry weather returns to Southeast Arizona Thursday into next week with high temperatures returning to above seasonable levels next week. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson