In a surprising turn of events, the Pacific Northwest is set to face a significant shift in weather patterns, as a rare atmospheric river approaches the region this Sunday. This unexpected weather event is expected to bring moderate to heavy rainfall across the Oregon Coast and Willamette Valley, with rain totals potentially exceeding an inch by Monday night.

Weather experts are predicting that the intensity of the storm may cause local ponding on roadways, urging residents to exercise caution while traveling on Sunday. The coastal areas and the Cascades could experience even more substantial rainfall, with the possibility of accumulating up to four inches between Sunday and Monday.

This wet weather trend, accompanied by cool daytime highs ranging from the low- to mid-60s, is expected to persist throughout the early part of the following week. However, by Monday afternoon, the continuous rain will transition into intermittent showers.

Interestingly, while the Pacific Northwest braces for this stormy weather, a shift towards summer-like heat is expected to occur in the western half of the country by late next week. A ridge of high pressure will begin building by the middle of the week, resulting in temperatures reminiscent of summer.

Looking ahead to the end of the week, afternoon temperatures in the Portland metro area could reach the upper 80s or hover around 90 degrees on Friday, indicating a swift change in weather conditions from the current rainy spell. However, before the arrival of sunshine and warm temperatures, residents are advised to prepare for the impending rain by ensuring they have the necessary rain gear.

As the situation unfolds, locals are urged to stay updated on the latest weather forecasts provided by KOIN 6, keeping an eye out for any potential changes or advisories.