Weather Models Explained

Global Forecast System

The flagship U.S. global model, free and widely used around the world.

European Centre (IFS)

Often regarded as the most skillful global model in the medium range.

Global Deterministic Prediction System

Canada's global model, a useful third opinion alongside the GFS and ECMWF.

Icosahedral Nonhydrostatic Model

Germany's global model, increasingly used for comparison in North America.

UK Met Office Unified Model

The United Kingdom's global model.

AI Global Forecast System

NOAA's machine-learning global model, trained on decades of GFS and reanalysis data and run alongside the GFS.

ECMWF AI Forecast System

ECMWF's machine-learning model, trained on ERA5 reanalysis and run alongside the traditional IFS.

Rapid Refresh

An hourly regional model that also drives the HRRR.

Regional Deterministic Prediction System

Canada's regional model — a useful companion to the RAP over Canada and the northern border states.

High-Resolution Rapid Refresh

An hourly-updating storm-scale model built for short-term forecasting.

Rapid Refresh Forecast System

NOAA's next-generation storm-scale system, designed to eventually replace the RAP and HRRR.

Rapid Refresh Ensemble (members 1–5)

Five storm-scale ensemble members built on the Rapid Refresh system — a convection-allowing ensemble, so it is listed with the storm-scale models. The model menu lists them one by one as REFSm1 through REFSm5.

High-Resolution Deterministic Prediction System

Canada's storm-scale model, similar in spirit to the HRRR.

MPAS-based RRFS (GSL advanced configuration)

An experimental storm-scale run from GSL built on the MPAS unstructured-mesh core, used to test RRFS ideas in real forecasts.

NSSL MPAS run (HTPO configuration)

A National Severe Storms Laboratory experimental MPAS run using one specific physics configuration, produced for severe-weather test beds.

NSSL MPAS run (RN configuration)

Another NSSL experimental MPAS run with a different physics configuration, produced alongside the HTPO run for severe-weather test beds.

Global Ensemble Forecast System

A group of about 30 GFS-based runs that show the range of possible outcomes.

ECMWF Ensemble (ENS)

The European ensemble with about 50 members.

ECMWF Ensemble — open-data subset

The freely published members of the European ensemble — the same system, with fewer members than the licensed full run.

ECMWF AIFS Ensemble

The ensemble version of ECMWF's AI model, showing where the machine-learning forecast could go.

Canadian Medium-range Ensemble

Canada's global ensemble — a third source of odds next to GEFS and EPS.

ICON Ensemble Prediction System

The ensemble version of Germany's ICON model.

Met Office Global Ensemble

The UK Met Office's global ensemble, often used for tropical and North Atlantic guidance.

National Blend of Models (NWS Blend of Models)

A statistically calibrated blend of many models, used as a starting point by the NWS.

Climate Forecast System

NOAA's coupled ocean–ice–atmosphere model, used for weekly-to-seasonal outlooks rather than day-to-day weather.

ECMWF Ensemble weekly means

Averaged weekly views of the European ensemble, meant for week-2-to-month signals rather than daily weather.