Monday is the last mostly dry day before rain sweeps Portland through Thursday

When you’re basking in high 70s and partly sunny skies early Monday, it’ll be hard to imagine a sky full of rain clouds and wet pavement, but it’s coming.

The National Weather Service says an approaching front will move inland later in the day, bringing rain to the coast and potentially bringing some light rain to the Willamette Valley late Monday in the afternoon or evening.

Portland has a 20% chance of rain after 2 p.m., but before that, skies will be cloudy early in the day, then slowly clearing to mostly sunny. The high should reach 71 degrees.

The front will weaken as it crosses the Coast Range, but Portland still has a 50% chance of showers overnight.

By late Tuesday morning, we will have transitioned to steady rain. High temperatures will drop to around 64 degrees and the chance of rain increases throughout the day. A new system will closely follow the original front and increase the amount of rain in the evening and overnight.

The best chance for widespread rain will be Tuesday night through Wednesday. Models show rainfall amounts of up to half an inch in the interior valleys and the Portland metro area. The maximum temperature will be 59 degrees.

The rain will taper off to showers on Thursday and there is a chance of a thunderstorm in the afternoon. The maximum will be around 56 degrees.

A note to travelers and mountain recreationists: Snow is expected to return to the Cascades on Thursday with snow levels dropping to 4,000 feet by Wednesday night. There could be 4 to 6 inches of snow around the higher passes by Thursday afternoon. Be sure to check TripCheck.com before you head out for mountain road conditions.

Extended forecasts show clarity on Friday and some warming. Some models show the return of widespread rain over the weekend.