Forecasts - Days to Seasons

For predictions on timescales from days to seasons, we use the European Centre for Medium Range Weather Forecasting (ECWMF) Integrated Forecasting System [link].  

51 ensemble members are provided for each forecast:

  • Medium range forecasts (1-15 days); forecasts issued twice per day

  • Extended range forecasts (16-46 days); forecasts issued twice per week

  • Long range forecasts (1-7 months); forecasts issued once per month


Our selection of the ECMWF system is based upon our judgment that it is currently the best forecast system in the world.  Our judgment is derived from extensive forecast evaluation and our experience in using this forecast system for research and for client-driven operational forecasts.

For some forecast products, we also use the following NOAA NCEP forecast products:

  • Global Ensemble Forecast System (GEFS): (1-15 days); 21 ensemble members issued 4 times per day

  • Climate Forecast System (CFSv2) (9 month forecasts); 4 ensemble members per day out to 9 months; 16 ensemble members per day out to 45 days

CFAN’s forecast products use the ECMWF and NOAA forecasts as the basis for extensive statistical adjustments, advanced forecast modules and ensemble interpretation.


Reliability and speed


CFAN has been providing operational, web-based forecasts using ECMWF forecast products since 2007. Our staff is dedicated to maintaining accuracy, speed, and ease of use of our forecasts.


To insure the reliability and timeliness of our forecast we have implemented the following procedures:

  • Hardware – from server redundancy to the latest storage array fail safes and web server load balancing, all elements of our hardware infrastructure have redundancy elements built in to ensure uptime and forecast availability.

  • Data – all data utilized in the CFAN forecasting process is checked for accuracy and completeness, with automated correction systems kicking in when needed.

  • Forecast – should problems arise with forecast or historical data that can impact forecast quality, automated correction techniques are employed and staff are notified so reviews can be made prior to products becoming available to clients.

  • Quality Assurance – continuous evaluation of forecast inputs and outputs using automated systems and human oversight.

  • Alert System – 24/7 on-call staff to respond to our automated alert system and to provide client support.