Atmospheric rivers—long, narrow bands of concentrated moisture—are responsible for some of the most intense rainfall and flooding events on the U.S. West Coast. Improving forecasts for these high-impact storms is critical for protecting lives, property, and water resources. CIRES and NOAA Global Systems Laboratory researchers are developing two cutting-edge atmospheric river prediction systems designed to tackle this challenge.

Regional high-resolution prediction 

One system focuses on short-term, high-resolution forecasts for the next three to five days. Covering a domain where two-thirds is ocean, this forecast platform will leverage data from satellites, GPS signals, and sensors dropped from aircraft to improve forecast accuracy over water. For the western U.S., surface, aircraft, and radar observations will enhance predictions of how much rain will fall.

This platform also offers an exciting opportunity to test innovative observation technologies, such as floating balloon soundings over the ocean from Sorcerer, a company exploring collaboration with researchers. Discussions will continue at the upcoming American Meteorological Society meeting. In preparation, scientists are staging data for retrospective experiments on major atmospheric river events from last December, with plans to launch a real-time version later this year during peak atmospheric river season.

Global Variable-Resolution prediction 

Atmospheric rivers impact other parts of the world, too. The second system takes a global approach, combining a high-resolution 3-kilometer inner domain focused on atmospheric rivers with a gradually coarser 15-kilometer resolution elsewhere. This unique design allows for longer forecasts, up to seven to ten days, while capturing both large-scale global weather patterns and fine-scale convective features in atmospheric river regions. Continuous global cycling ensures the system can track evolving weather systems worldwide, improving lead times and delivering detailed forecasts. 

Why it matters

These innovations promise to improve prediction skill for atmospheric river events, which are critical for water supply and flood management. By integrating new observation technologies and advanced modeling techniques, scientists aim to provide communities with better tools to prepare for extreme weather.

Stay tuned for updates as these systems move from development to real-time testing during the upcoming atmospheric river season.