Portland, much like Seattle to the north, receives around 1,090 mm (about 43 inches) of rain a year, most of it falling as long stretches of light-to-moderate rain between October and April rather than sudden violent downpours, shaped by Pacific storm systems interacting with the surrounding Cascade and Coast ranges. Occasional atmospheric river events bring much more intense rainfall and can trigger landslides in the hillier parts of the metro area and flooding along the Willamette River. Because individual storms are usually mild, radar here is mainly useful for timing exactly when a band of heavier rain or wind will move through during an otherwise drizzly stretch. NWS Doppler radar KRTX (Portland) covers the region.
Learn more: How Does Rain Radar Work? · Open the full Rain Map