Dataset supporting "Predictable Patterns of Seasonal Atmospheric River Variability Over North America During Winter"

A dataset containing selected outputs from real time forecasts and hindcasts produced by the Seamless System for Prediction and Earth System Research (SPEAR). Variables in the dataset include atmospheric river frequency, surface temperature, 500 hPa geopotential height and precipitation. The period covers 1991 through 2023 averaged seasonally in the months December through February. Forecasts initialized in a given month "MM" are stored in subdirectories and files with the indicator "iMM," where MM varies from 03 to 12 (March through December). A pair of python scripts demonstrating average predictability time analysis are also included. This data is associated with the study "Predictable Patterns of Seasonal Atmospheric River Variability over North America during Winter," by Clark et al.