True, maybe not for SeaTac. But I think my area and east towards the foothills could've pulled it off (115-120 range). Just needed the easterly flow to keep descending.
I think the Puget Sound existing as it does will perma-lid temps on the Seattle ismuth to around 110-115, barring some RPC4.0 tier thermal reworking of the ocean-atmosphere heat budget. The GFS was smoking some low-res pack when churning out those runs.