You may have heard meteorologists using the phrases "atmospheric river" and "Pineapple Express" when talking about wet weather in California, but what do they really mean?
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00:00Welcome back to AccuWeather Ahead. This time of year is normally when we head into the peak season for what we call an atmospheric river.
00:07And when that atmospheric river comes directly from Hawaii, that's what we call the Pineapple Express.
00:12And this can bring heavy, heavy rainfall, even snow, to the West Coast.
00:17So what is the atmospheric river and what is the typical setup that we normally see?
00:21Well, what ends up happening is that when you get really strong winds over the ocean, all that moisture has to go somewhere.
00:26So the winds actually direct all that moisture towards the coast.
00:30So that's what ends up happening here with an atmospheric river.
00:32So stronger winds, they can create narrow bands here of extremely high moisture contents.
00:38We're talking very humid air moving in.
00:41And the strength of those winds in that atmospheric river, well that depends primarily on the wind speed and the locations where the winds are funneling all that moisture.
00:50So this is your typical setup.
00:51We will have an area of low pressure to the north of the atmospheric river and an area of high pressure to the south.
00:56And those opposite rotations there of those centers, what ends up happening, that creates the perfect environment for what we call that atmospheric river.
01:04And once again, if the atmospheric river has its origins across Hawaii, that's why we call it the Pineapple Express.
01:11So whenever that atmospheric river comes on shore, what ends up happening is that these coastal bands bring heavy rainfall here to the coastal regions.
01:18And if that moisture can maintain as it goes over the coast and it goes into higher elevations, you get mountain lift, which can create some heavy snowfall totals here for some areas.
01:28And it looks like we'll see a very similar setup for that as we head into the weekend.
01:32So the atmospheric river, once again, if it originates in Hawaii, that's whenever we get the Pineapple Express.
01:38So that's what we're going to be looking at here as we head throughout the weekend and into early parts of next week because we will be watching out for a flooding risk associated with that as we head into the weekend.
01:47Stay right here with AccuWeather ahead. We'll be right back.