Versions Compared


  • This line was added.
  • This line was removed.
  • Formatting was changed.

The HRES (current horizontal resolution 9km, vertical resolution 137 levels) is a single run forecast model run twice daily giving forecasts to Day10 based on 00UTC  and 12UTC data times.   The HRES  provides a detailed description of future weather and also for 3.5 days at 06UTC and 18UTC.  HRES is separate from the medium range ensemble (ENS) and runs slightly earlier.   

The horizontal and vertical resolutions of the medium range ensemble (ENS) became the same as for the HRES after the upgrade to IFS (Cy48r1) introduced in June 2023.  The HRES forecast and the unperturbed ENS control forecast are meteorologically equivalent and equally skilful on average.  They have the same physical and dynamical representation of the atmosphere and use the same parameterisation of sub-gridscale effects.  However, they can diverge on a day-to-day basis due to small technical differences and the chaotic nature of the atmosphere.  The HRES will continue for the time being for ease of use by customers and users. 

On average, HRES is the most accurate single-run realisation of the broadscale weather patterns.  But any individual HRES forecast may not be the most skilful compared to ENS member forecasts, and in isolation it cannot provide an estimate of forecast uncertainty or confidence.

High horizontal and vertical resolutions of HRES and ENS bring the benefit of feeding energy from smaller to larger scale features (as happens in the real atmosphere) but with the risk of developing or amplifying spurious small features or suppressing existing ones that should be retained. 

HRES is coupled to the Wave model (ECWAM) and to the Dynamic Ocean model (NEMO) and affects development of Tropical Storms.

Definitive information on the ECMWF dissemination schedule and products can be found in the the Catalogue of ECMWF real-time products (ENS: Set 1).