A fall-like weather pattern is settling over the Portland area this week. Monday will bring sunshine and warmer temperatures, with highs expected to reach the mid to upper 70s in the interior lowlands and 60s along the coast. There’s a slight chance of hitting 80 degrees in the Willamette Valley, making it an ideal day for outdoor activities.
However, the dry spell will be short-lived. A strong frontal system will move in late Monday night, bringing widespread rain and cooler temperatures by Tuesday. Rainfall totals through Wednesday morning are forecast to be 0.35 to 0.70 inches in the lowland valleys, with up to an inch possible in the Coast Range and Cascades. Temperatures will drop significantly, with highs in the low 60s and 50s in the higher elevations.