Multisatellite Water Vapor Products for Forecasters at the Weather / Climate Interface

Water vapor is the fuel for much of what we perceive as weather, including the formation of clouds and precipitation. Since the primary source of water vapor is evaporation over the oceans, satellites have always provided essential observations. Weather forecasters commonly use two satellite-driven multisensor blended products - Total Precipitable Water (TPW) and Advected Layer Precipitable Water (ALPW) - to track pipelines of moisture which support heavy precipitation. Each product is driven primarily by passive microwave data, but surface and satellite infrared data contribute to blended TPW.

ALPW allows forecasters to see the origins and transport of mid- and upper-level water vapor. When converging and aligned with low-level moisture this can be the difference between an ordinary weather event and an extraordinary one. Recent case studies and applications of ALPW for several different hazardous weather events and floods will be presented.

As satellite records begin to cover more decades, products to place the water vapor amounts into historical context become possible. Results from a new percentile ranking of ALPW values for atmospheric rivers and other extreme precipitation events will be shown. This product was evaluated by forecasters in a flash flood forecasting experiment at the NOAA Weather Prediction Center in summer 2023.

Experiences on the path from research at a cooperative institute to operational products widely used by forecasters will be described.