Atmospheric River Hazard Tool

Operational Forecast
Historical Cases

Supported by the National Science Foundation Coastlines and People Program: #2052972

Model Climate: How does this forecast compare to past forecasts with similar lead time?

Plot description: Model Climate (M-Climate) is generated based on NOAA’s Global Ensemble Forecast System, version 12 (GEFSv12) reforecast data (2000-2019), for integrated water vapor transport (IVT), freezing level (Z0), 1000-hPa wind (UV), and Quantitative Precipitation Forecasts (QPF) (shading, percentile rank). This places important forecast elements in the context of reforecasts with the same lead time and at similar times of year. For example, large M-Climate Percentile Rank IVT values indicate GEFS ensemble mean IVT values are large for a given lead time. The contours show the ensemble mean forecast IVT (kg m-1 s-1), freezing level (feet), 1000-hPa wind (knots), and QPF (in 3-hr-1) based on NOAA’s Global Ensemble Forecast System. The AR Hazard Index summarizes grid-level conditions by assigning scores (1–5) based on extreme M-Climate percentiles of IVT, freezing level, wind, and QPF. Additional points are given for prolonged IVT extremes and wind/IVT orientations perpendicular to topography. The image on the right shows the potential precipitation hazards that could be messaged based on the AR Hazard Index that could potentially impact people and infrastructure.

Domain: 

Data Sources

  • National Centers for Environmental Prediction (NCEP) Global Ensemble Forecast System (GFS) Model obtained from NOAA/NCEP at 0.5-degree resolution via NOMADS.
  • The NOAA GEFS Reforecast version 12 data at 0.25-degree resolution was obtained from NOAA via Amazon AWS.