The North American Ensemble Forecast System (NAEFS) is run at 00 and 12 UTC each day with 40 ensemble members plus two controls, split evenly between the GEFS (Global Ensemble Forecast System) at NCEP and the CEFS (Canadian Ensemble Forecast System) at the Canadian Meteorological Center (CMC). Further details on the GEFS can be found here, and on the CEFS here. At present, only the GEFS is run (with its 20 perturbations and 1 control) for the off-time forecast cycles at 06 and 18 UTC.
Data is interpolated to 1°x1° resolution out to 384 hours. All runs are shown out to 180 hrs at 6-hour intervals, then to 384 hours at 12-hour intervals. For 00, 06, 12, and 18z ensemble forecasts over the last 10 days, click on the links in the table below: