Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
311 FXUS65 KTWC 061600 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 900 AM MST Sun Sep 6 2026 .SYNOPSIS... Expect isolated to scattered thunderstorms each afternoon and evening into early next week, with a potentially more active period later next week. The main threat will be heavy rainfall leading to localized flash flooding. High temperatures will will fluctuate between near normal and a few degrees below normal. && .UPDATE... Very light showers that developed early this morning in eastern Pima county have been gradually dissipating and will continue to do so as the morning progresses. Mid- and high-level clouds will continue today as southwesterly flow aloft brings a steady supply of moisture to the area. This afternoon expect a few more thunderstorms than yesterday, but not by much. Best chances for storms remain along the International Border and along the AZ/NM border where the best instability is. With any storm, the main concern is locally heavy rainfall and isolated flash flooding. && .DISCUSSION... Portions of Southeastern Arizona is currently under scattered mid to high level clouds, mainly Tucson south and eastward. Moisture from Hurricane Marie has moved into the region, with the main plume of moisture to the north of our neck of the woods, however PWs have increased especially in Western Pima County at 1.6 inches. The rest of Southeastern Arizona still has plenty of moisture elsewhere with PWs between 1.3 to 1.5 inches. The trough to the northwest that has been keeping the SW flow aloft over the pas days will slowly begin to move eastward and shift the flow to be Southerly as the high pressure begins to slowly drift back west today. Expect a few more thunderstorms than yesterday, but not by much. Best chances for storms remain along the International Border and along the AZ/NM border where the best instability is. With any storm, locally heavy rainfall and isolated flash flooding. Current CAMs are also showing outflows from Sonora, Mexico coming in from the south in the evening, so overnight activity can`t be ruled out tomorrow night. Coverage in storms looks to increase gradually this work week, with the best instability and forcing in the later half of the week. As always with the monsoon, it`s hard to see which day will be the most active out of the bunch, but details will become clearer as we get closer. With the available moisture and weak flow aloft, the primary threat continues to be the flash flooding potential from efficient heavy rainers, with strong outflow winds as a secondary threat. Temperatures will be within a couple of degrees of normal through Wednesday, then dropping to below normal levels late next week. && .AVIATION /15Z SUNDAY THROUGH 15Z MONDAY/... Valid thru 07/12Z. FEW to SCT clouds between 7-10 k ft agl today. Isolated to scattered TSRA along International Border with VCSH and possibly VCTS for KOLS. Activity quickly wanes after sunset. SFC winds less than 12 kts, with the exception of any outflows around convection. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Expect daily isolated showers and thunderstorms into early week, before becoming more scattered the rest of the week. Heavy rainfall leading to flash flooding will be the main threat. Temperatures will be around normal to a few degrees below normal into early next week. Minimum relative humidity values mainly 20 to 45 percent in the valleys and 30 to 60 percent in the mountains over the next week. Winds will generally remain less than 15 mph and terrain driven through the week. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Malarkey DISCUSSION...Tetrault Visit us on Facebook, X, YouTube, and at weather.gov/Tucson