National Weather Service guidance and ensemble model consensus currently favor a Seattle high near 74–77°F on August 12 amid moderate onshore flow from the Pacific that enhances marine-layer influence and limits daytime warming. Recent observations show highs in the mid-to-upper 70s under similar zonal flow aloft, with no strong offshore component or subsidence to drive temperatures into the 80s. Subtle differences in the 76–77°F versus 74–75°F bins reflect uncertainty in exact afternoon mixing depth and cloud cover timing, while lower-probability warmer outcomes would require a sharper easterly shift that current runs do not support. Updated model cycles and evening NWS briefings remain the key near-term catalysts.