GFS 12z ensemble median for SFO on April 29 projects a 55°F high, aligning with ECMWF's persistent onshore flow indicating a deeply entrenched marine layer. This synoptic setup caps advective warming. Coastal NWS guidance reinforces below-normal thermal profiles. The narrow 56-57°F window is highly probable given the model convergence on cooler conditions. 90% YES — invalid if marine layer breaks earlier than modeled.
GFS 12z ensemble median for SFO on April 29 projects a 55°F high, aligning with ECMWF's persistent onshore flow indicating a deeply entrenched marine layer. This synoptic setup caps advective warming. Coastal NWS guidance reinforces below-normal thermal profiles. The narrow 56-57°F window is highly probable given the model convergence on cooler conditions. 90% YES — invalid if marine layer breaks earlier than modeled.
