The official National Weather Service for western Washington tomorrow is favorable (sunny skies and temperatures in the mid to upper 50s), but are they being too pessimistic? Might tomorrow be much warmer and perhaps approach the record of 65F at Sea-Tac?
Perhaps. For the University of Washington in Seattle the NWS forecast is 56F on Monday.
Let's take a look at the latest runs of the UW high-resolution (4-km grid spacing) WRF forecasts. At 7 AM, it shows easterly flow and band of warmth in the Cascade foothills. You know why that warm band happens? Downslope warming along the western slopes of the Cascades.
A warm front is moving northward across our region right now (see map), with a low and associated cold front approaching from the west.
Data above Seattle right now shows moderate southwesterly flow above us now, with temperatures greatly warming over the past 24 h (by 6C or 11F).
And did I mention the winds? The foothills may get blustery with moderate easterly flow (see graphic for tomorrow at 7 PM).