Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
387 FXUS65 KTWC 031715 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 1015 AM MST Thu Jul 3 2025 .SYNOPSIS...Monsoon moisture remains across southeast Arizona today, however thunderstorm coverage will be less compared to Wednesday. The storms that do occur will be capable of producing locally heavy rain. A drying trend is expected for Independence Day and this weekend with storm coverage more isolated and focused on locales south of Tucson. Temperatures will remain below normal through Friday before warming back up to above normal levels by Sunday and continuing through much of next week. && .DISCUSSION...The one thing to know about the nature of Monsoon season, in general...the day after an active thunderstorm day is usually followed by a down day as the atmosphere has a difficult time recovering. That doesn`t mean that storms will not occur, because they will. It is just that despite having ample moisture in place like we do today, it is difficult to realize enough CAPE for deeper/strong convection. This is where we find ourselves today. The latest GOES PWAT imagery indicates PWAT values around and 1 inch to the east and southeast of Tucson, around 1.20 inches in Tucson, and an area aoa 1.50 inches across Maricopa and western Pinal counties. This matches up with the 03/12Z KPSR sounding that reported a PWAT of 1.52 inches. This moisture is reflected in the lower levels, as surface dewpoints in the lower 60s make for a muggy feeling across the entire forecast area. The upper pattern today is defined by an upper trough across Nevada, with high pressure over Texas/northeast Mexico. The upper trough will continue to lift NE today, with the southern periphery of the 500 mb trough axis swinging through our neck of the woods this afternoon. Normally this would be a bigger player in providing a lifting mechanism, especially given the ample moisture in place, but again, the atmosphere is trying to recover from yesterday. I would still expect to see scattered thunderstorms develop early this afternoon, especially along an axis from Three Points to Sierra Vista, which will align itself with the best deformation aloft from the trough passage. The main threat from today will be locally heavy rainfall with the thunderstorms, and to a much lesser extent gusty and erratic thunderstorm outflows. We can expect a downturn in thunderstorm activity for Independence Day and into the weekend as high pressure builds into the area from the south, extending across Southeast Arizona and Sonora Mexico. The unfortunate side effect from this is that we will begin to warm up to above normal readings Sunday into early next week. The high then is progged to shift north toward the Four Corners by the middle of next week. Although this should be a more favorable location for thunderstorm activity, the 300 mb high stacking on top of will somewhat limit deep convection. With direr air setting up across the eastern CWA, and a surge of moisture moving up the Gulf early next week, the main threat from thunderstorms will be strong and gusty outflow winds east of Tucson, with the potential for heavy rainfall from Tucson west. && .AVIATION...Valid through 04/18Z. SCT 7-12k ft becoming SCT-BKN 7-12k ft AGL from KTUS eastward thru 04/05Z before diminishing thru end of valid period. Scattered SHRA/TSRA is expected 03/20Z- 04/04Z with CIGS BKN 5-8k ft AGL and gusty outflow winds up to 35 kts. Surface winds generally WLY 8-13 kts today, becoming SLY less than 10 kts overnight. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Slightly below normal temperatures through Friday, then warming back this weekend into next week. Expect scattered showers and thunderstorms this afternoon into evening with locally heavy rainfall. A decrease in thunderstorm activity is expected Friday through the weekend as the area transitions into a low grade monsoon pattern. An eventual uptick in monsoon activity is expected next week but will be dependent on how quick the high pressure aloft shifts north. Winds generally light and under 15 mph with the exception of gusty and erratic winds up to 35-45 mph near any thunderstorms. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson