SAN DIEGO - Everyone's waiting to see if El Niño will deliver this winter. It turns out, we should also be keeping an eye on "atmospheric rivers" in the sky, which could increase our chances for rain.
Atmospheric Rivers are a key source of water vapor that when combined with a winter storm can drop a lot of rain and snow. And much of that could fall along the West Coast.
"The El Niño conditions can contribute much more water vapor to the atmosphere,” said John Helly of the San Diego Supercomputer Center at UC San Diego.
Helly and other scientists from around the region are using the San Diego Supercomputer to look deeper into atmospheric rivers. It's part of the CalWater 2015 project. They want to better be able to determine where the rain will fall, how much and for how long.
"Those factors determine very much the risk of flooding, as well as the opportunity to be able to capture the water to help our water supply,” said Helly.
A well-known example of a type of strong atmospheric river that can hit the west coast is the "Pineapple Express," since it brings moisture from Hawaii.
One such river produced more than 40 inches of rainfall in the mountains of Southern California in only four days in early January 2005.
Another atmospheric river contributed to all the rain and flooding Northern California got last winter.
“Those are the kinds of things we want to be able to predict more effectively to give us longer lead times to prepare for emergency response,” said Helly.
Thanks to supercomputer models, scientists have also been better able to predict winds in the central valley during a storm. That’s important because that could also affect how the storm plays out for the rest of the Southwest.