Radar — KEMX
Surface Analysis — Western U.S. (Central)
Satellite
Nearest monitored road: East Broadway Boulevard (Primary)
Expect daily afternoon and evening showers and thunderstorms this week with day to day variability in coverage and strength. High temperatures will warm to 7-12 degrees above normal thursday into the weekend with an extreme heat warning through sunday.
Activity thus far has been confined to northern graham/greenlee, with a couple transient supercells already noted. These initial cells should continue to push NW and out of the cwa within the next hour or so.
For the rest of the day...looking at the current mesoanalysis shows mlcape 1000-2000 j/kg with pockets slightly over 2000 j/kg in southern cochise county. Effective SHEAR is modest around 20-35 KTS, which supports another favorable environment for strong to severe multicells and one or two transient supercells. Cams also show this scenario, but coverage would be isolated at best. Main threats will be wind gusts to 60 MPH and marginally severe hail to around 1" in diameter. While heavy rain is possible, flash flooding would be very localized given the progressive motion of any storms.
Tomorrow is tricky forecast, as there are hints of another large sonoran mcs which could skirt or sneak into extreme southern az. While confidence is low at this time, its worth mentioning the possibility. This would increase a localized severe/flash flood risk along the international border. The flash flooding risk would be greatest for areas saturated in the san pedro watershed.
No changes to the extreme heat warning as heat will build the rest of week, peaking this weekend. Naefs mean 500 mb heights at the 99.5 percentile or max compared to the cfsr climatology thursday into the weekend. Temperatures warm 7-12 degrees above normal during this time frame leading to widespread areas of major to extreme heatrisk. Because of this an extreme heat warning remains is in place thursday through sunday. The two warmest days look to be friday and saturday with tucson possibly seeing 110 degrees both days. Nbm probabilities for tucson international to hit 110 degrees have dropped into the 20-35% range both days, but still quite signfciant.
Storm chances drop to their lowest of the week thursday, before slowly ramping back up by the weekend. Greatest coverage remains south and east of tucson through the rest of the week, with some day to day variability based on the previous days convection.
VFR through the forecast period. Few to sct cloud decks this afternoon and evening aoa 7-9k ft agl. Vcts in kdug this aftn/evening with iso/sct coverage of ts/shra south and east of ktus. Sfc winds less than 12KTS, with the exception of any ts outflow winds.
High temperatures will remain above normal this week with an extreme heat warning in place thursday through saturday. Expect daily chances of afternoon and evening showers and thunderstorms with day-to-day variability on coverage of storms into the weekend. Any thunderstorm will bring a threat of severe, erratic wind gusts as well as brief heavy rainfall and an isolated threat of flash flooding. Min rh values will be 20-40 percent in the lower deserts through at least mid-week. By mid to late week, min rh could dip into the teens in the lower deserts. Winds this weekend will mainly be light and under 12 MPH outside of thunderstorms.