Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
751 FXUS65 KTWC 191055 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 355 AM MST Fri Jul 19 2024 .SYNOPSIS...Temperatures will remain 4 to 7 degrees above normal through the rest of this week, with typical mid-July moisture levels across the region. This will result in the daily chances for showers and thunderstorms. The main threats will continue to be strong gusty outflow winds and heavy rainfall leading to localized flash flooding. && .DISCUSSION...There is substantially less nocturnal convection currently ongoing on across southeast Arizona and along the International Border compared to this time yesterday. Scattered clouds are seen across most of the area with a complex of storms across north central Mexico. Meanwhile, an MCV is developing overhead. The lack of lingering nocturnal convection will lead to another afternoon with isolated to scattered showers and thunderstorms. CAMs/HREF are specifically depicting storms forming off the White Mountains and higher terrain areas around noon to 2 pm MST before some of the members hint at the storms pushing off the elevated terrain into the valleys similar to yesterday. While those members may hold onto some of the convection into the valleys, the maintenance of convection yesterday afternoon over the valleys may hinder the storms from remaining quite as robust as the low levels were worked over a bit. Thus, looking at more isolated chances for storms in the valleys this afternoon with scattered expected over the higher terrain lasting into. For the storms that can propagate off the higher terrain, gusty outflow winds and isolated instances of flash flooding may occur. Looking at the upper level pattern, the mid/upper level high currently centered over north central AZ will migrate west/northwest resulting in the flow pattern gradually becoming northerly/northeasterly. Over the weekend into early next week this pattern will support an uptick in storms forming off the Mogollon Rim/elevated terrain and propagating southwest. Guidance has backed off on temperatures for tomorrow, but the probability of hitting 105 or higher tomorrow at Tucson International Airport is around 75 percent. Inevitably, it will be another warm desert day. && .AVIATION...Valid through 20/12Z. SCT-BKN clouds at 8k-12k ft AGL diminishing between 19/12Z and 19/18Z before developing again associated with SCT TSRA/SHRA thru 20/06Z. MVFR conditions in TSRA, with mountain obscurations, vsby reductions and wind gusts to 40+ knots. Outside of TSRA, SFC wind at most locations 12 knots or less favoring NWLY direction during the afternoon/early evening hours and variable in direction at other times. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Deeper moisture remains across southeast Arizona, with typical July moisture levels expected into at least early next week. This will result in the daily cycle of mainly afternoon and evening showers and thunderstorms. The main threats will be strong, gusty and erratic outflow winds and heavy rainfall leading to localized flash flooding. Minimum relative humidity values will be 20-30 percent in most lower elevation locations and 25-40 percent in mountain areas. Away from thunderstorms, 20-foot winds will generally be 15 mph or less, with afternoon/early evening gusts to 20-25 mph and light winds overnight. Wind direction during the afternoon hours will primarily be west to northwest through the weekend, especially from Tucson westward and in the upper Gila River valley. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ DVS Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson