Climatological mean high for SF in May is 63-65°F. A 50-51°F peak demands anomalous troughing or an exceptionally deep, persistent marine inversion completely blocking diurnal insolation, an infrequent synoptic setup post-April. Even strong onshore marine advection rarely keeps the daily high this suppressed. Probability of exceeding 51°F is high. 90% NO — invalid if GFS 00z on May 7 projects 850mb 0C isotherms persisting over the Bay Area all day.
Climatological mean high for SF in May is 63-65°F. A 50-51°F peak demands anomalous troughing or an exceptionally deep, persistent marine inversion completely blocking diurnal insolation, an infrequent synoptic setup post-April. Even strong onshore marine advection rarely keeps the daily high this suppressed. Probability of exceeding 51°F is high. 90% NO — invalid if GFS 00z on May 7 projects 850mb 0C isotherms persisting over the Bay Area all day.
