ZCZC SPCSWOMCD ALL ACUS11 KWNS 042140 SPC MCD 042140 AZZ000-NVZ000-CAZ000-042345- Mesoscale Discussion 1765 NWS Storm Prediction Center Norman OK 0440 PM CDT Sun Sep 04 2022 Areas affected...Lower Colorado River Valley into southern California Concerning...Severe potential...Watch unlikely Valid 042140Z - 042345Z Probability of Watch Issuance...5 percent SUMMARY...Isolated to scattered thunderstorms will become more likely through the late afternoon and evening hours. A few storms may be strong to severe with the potential for strong winds. A watch is not anticipated at this time. DISCUSSION...A few attempts at convective initiation have been noted over northern Yavapai, southern Coconino, and eastern Mohave counties over the past 1-2 hours. These early attempts have largely failed due to lingering inhibition and weak forcing for ascent, but increasing cumulus across the region over the past 30 minutes or so suggests a continued decrease in inhibition and strengthening orographic lift over the terrain. A few deeper towers with 30-40 dBz radar returns have been noted in the past 15 minutes, suggesting that sustained thunderstorm initiation is becoming more likely within the next hour. Storms that can mature through the late afternoon and early evening hours will likely acquire some storm-scale organization given adequate buoyancy and modest deep-layer shear. While sporadic marginally severe hail is possible, strong to severe winds appear to be the most likely hazard given high cloud bases and steep low-level lapse rates near 9 C/km. Further west into southern CA, isolated thunderstorms are struggling to mature in a similar thermodynamic regime, but may undergo some intensification over the next 1-2 hours. This activity will similarly pose a strong/severe wind threat into the evening hours. Given the localized/weak forcing for ascent, storm coverage will most likely remain too limited for watch issuance. ..Moore/Hart.. 09/04/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGZ...PSR...VEF...SGX...HNX...LOX... LAT...LON 35281247 34251264 34041461 34111700 34231831 34761877 35271876 35601829 35901604 36421417 36331299 35281247 NNNN