What in the world is a Pineapple Express, and how is it affecting the Bay Area?

SAN FRANCISCO (KGO) -- What is helping to bring the threat of flooding rains to the Bay Area on Wednesday is a weather phenomenon known as an "atmospheric river".

FORECAST: Strong storm on way to Bay Area with help of 'Pineapple Express'

A narrow band of moisture, typically only 250 miles wide, atmospheric rivers carry heavy rain and strong winds. When that narrow band of moisture originates near the Hawaiian Islands, it gets the nickname "Pineapple Express".

Wednesday will feature an atmospheric river event aimed right at the Bay Area which will likely result widespread 1" - 2" of rain with isolated spots over 3".

Along with the rain, winds will gust over 40mph at time. Flooding is a high threat, especially on our burn scars in the North Bay so be prepared to take action if needed. This storm ranks a 3, a strong storm, on the ABC7 Storm Impact Scale.

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