What is Pineapple Express or Atmospheric River on the way to North America?

Weather fronts push the Pacific Ocean out into the western coast of North America, extending from British Columbia, Canada down to San Francisco in northern California, and bears heavy rain and mountain snow.

An atmospheric river will then set up over northern California that extends into southern Oregon and Northern Rockies. Floods and landslides are possible with 380-500 mm (15-20in) rain predicted for some areas over the next six days.

It is expected to continue over the weekend and into Monday before moving further south towards Los Angeles and San Diego on Tuesday and Wednesday next week.

The weather is also very bad in Hawaii with strong winds, warnings about flash floods in place and 2-3 inches of rain expected. Conditions improve Saturday when low pressure pulls away,

However, the air that feeds the developing atmospheric river along the mainland west coast will still be tropical and originated from Hawaii. So this event can be referred to as a pineapple express.