Tuesday starts off much warmer with 6 a.m. temps in the mid 50s, whereas Monday's morning temps were in the mid 40s. Warmer temperatures mixed with mostly clear skies will pop up the heat Tuesday with a high expected of 85 degrees.

A smattering of marine air could filter into the Coast Range and potentially the south Willamette Valley in by the afternoon to keep the heating down just a bit. But the Portland metro area will make it well into the 80s.

Mostly sunny skies are expected for the day on Wednesday with highs near 80. But by Wednesday night clouds move back in and rain will make its way back into the valleys by Thursday.

Also on Wednesday, forecasters for the National Weather Service see some instability developing over the Cascades and foothills by afternoon, suggesting a slight chance of an afternoon and early evening thunderstorms in those areas.

Forecast models are in good agreement that moisture moves in by Wednesday night and rain will begin by very early Thursday morning. Temperature will drop considerably with this next system. Highs on Thursday will only be 65 degrees.