Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
175 FXUS65 KTWC 040822 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 122 AM MST Sat Oct 4 2025 .SYNOPSIS...Dry conditions will occur over the weekend into the middle of next week. High temperatures will be near normal this weekend, along with breezy southwest winds as a system moves to our north. High temperatures warm to 3 to 5 degrees above normal next week. A slight chance of precipitation returns by late next week. && .DISCUSSION...The large scale pattern has an upper low over south central Nevada and high pressure aloft across Texas into the mid Mississippi Valley. The upper low will move eastward across the Great Basin this weekend, with near zonal flow across the desert southwest. By early next week, the flow aloft turns southwesterly across the region. Late next week, moisture moves northward across Mexico into the southwestern United States. The upper low will move east across the Great Basin today, with high temperatures lowering to near seasonal levels this weekend. Highs will be in the upper 80s to lower 90s from Tucson westward and in the 80s across Santa Cruz, Cochise and Graham counties. This system will also result in gusty southwest winds this afternoon. Wind speeds will generally be 12-18 mph with gusts to 20-30 mph from Tucson eastward. Peak wind gusts this afternoon will be 30-35 mph across portions eastern Santa Cruz and Cochise counties. By early next week, the low will track east into the central plains and southwest flow aloft will prevail across the region. This will lead to warmer temperatures and highs 3-5 degrees above normal next week. For late next week into next weekend, there still remains a high degree of uncertainty in regards to the amount of tropical moisture advecting into the area. While it looks fairly certain EP99 will strengthen (90% chance of cyclone formation in 7 days) and move to the north/northwest, the amount of moisture moving into the desert southwest will depend upon position of the shortwave ridge in place when the moisture starts to push northward and the west coast trough forecasted to develop as this system moves north-northwest. CPC 6-10 day and 8-14 day outlooks continue to show 50-70% above normal precipitation chances across the area during this time frame. The latest grids have a slight chance of precipitation next Friday and Saturday. Stay tuned. && .AVIATION...Valid through 05/12Z. SCT-BKN clouds at 10k-12k ft AGL east of a KALK to KSAD line thru 04/15Z, then clear skies thru end of valid period. SFC wind variable and terrain driven at less than 12 kts til 04/16Z and again aft 05/04Z. Increasing SLY/SWLY SFC wind aft 04/16Z, with speeds of 12- 20 kts and gusts to 22-30 kts between 04/19Z and 05/03Z, with the strongest SFC wind southeast of KTUS in the vicinity of KALK and KDUG. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Dry conditions will prevail across southeast Arizona this weekend into the middle of next week. A storm system will move to our north this weekend, resulting in gusty southwest winds. 20- foot winds will be 12-18 mph and gusts to around 30 mph today, with the strongest winds southeast of Tucson across eastern portions of Santa Cruz and Cochise counties. Min RH values in the valleys will be in the 12-20 percent range over the weekend through early next week. RH values in the mountains will generally be in the 25-35 percent range. High temperatures will be around normal this weekend, warming back up to 3-5 degrees above normal next week. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Zell Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson