New Ensemble Probabilistic Forecasts Generation

North American Ensemble Forecast System (NAEFS) is an ensemble weather prediction system run jointly by Meteorological Service of Canada (MSC) and National Weather Service (NWS). It generates probabilistic products four times per day for North America, Alaska and the globe for up to 2 weeks in advance. NAEFS is prototype of THORPEX project and provides framework for transitioning from research into operation.

The generation and improvement of NAEFS probabilistic guidance are maintained and continuously enhanced through the developments of NAEFS statistical post-processing (SPP) system. In next NAEFS upgrade, some relatively mature SPP techniques will be introduced into the operational system, which include 1) the 1st moment bias correction technique with varied decaying coefficients (varied by lead time, domains and seasons) ; 2) Recursive Bayesian Model Process (RBMP) method to improve blending process (different weights) and 3) the 2nd moment adjustment to enhance ensemble spread.

Through NAEFS SPP study and development, future NAEFS products will provide high resolution (at NDGD grid) probabilistic guidance for CONUS (2.5km) and Alaska (3km). Meanwhile, in order to provide complete set of NDGD element, calibrated and downscaled probabilistic numerical guidance of cloud cover (globally and extend (CONUS) will be produced as well.