During the last day, strong easterly flow has developed aloft, something that is evident from the winds shown on the Seattle profiler. This strong easterly flow is associated with warm air (27F, 80F centered at around 600 m, if you look closely)
This morning there is a veneer of cool air with very warm air above, separated by a sharp inversion here in Seattle (see graphic) During the next few hours this cool air will get mixed out and the temperatures will surge upward...towards the upper 80s in many places.
The transition to warm, offshore flow was evident at some hilltop stations during the past day. The home of Peter Benda on Bellevue's Summit Community (around 1200 ft) experienced a rapid warming and drying in the middle of the night as southeasterly flow developed:
Enjoy the warmth..tomorrow will cool a bit (mid 80s) as the thermal trough slips into eastern Washington.