The Onshore Push of Marine Air into the Pacific Northwest

Areas west of the Cascade Mountains of the Pacific Northwest have a mild climate generally influenced by air flowing inland from the cool northwest Pacific Ocean. Warm, dry episodes in the warm season end with a return to this marine influence. The change can occur abruptly as a classic marine push, or in a more gradual fashion. A brief description of the marine push, as well as its impact on the public, is provided. The range of events in terms of abruptness and magnitude are highlighted, and comparisons are made between strong and weak cases. Synoptic and mesoscale features important for the forecast of the marine push magnitude are discussed.