Description of the upgrade

The Integrated Forecasting System (IFS) was implemented. The model cycles were renumbered with the introduction of IFS). The IFS is a major rewrite of the forecast model. The model identification field in the GRIB headers of products was changed to 111. Several meteorological modifications were introduced at the same time:
  • introduction of the 2 metre dewpoint SYNOP observations in the humidity analysis;
  • use of the sensible heat flux in addition to the latent heat flux to determine the cloud base mass flux in the shallow convection scheme;
  • inclusion of the latent heat release due to freezing of condensate in convective updraughts.
These modifications addressed certain problems which were noted in the Tropics over the last few months, in particular with precipitation and 2 metre temperature.

Implemented: 02 March 1994