A Pineapple Express forms when the jet stream dips south into the tropical Pacific near Hawaii, scooping up warm, moist air and carrying it northeast across the ocean. Named for Hawaii's famous fruit and the storm's origins near the islands, these powerful systems can dump the equivalent of 10 to 15 inches of rain over two to three days.

A prolonged atmospheric river event is set to continue delivering moderate to heavy rain across the Pacific Northwest

The first storm from the tail end of an atmospheric river brought light to moderate rain throughout the Los Angeles area.