| As an input to formulation of weather forecasts, aviation
forecasters use outputs from the numerical weather prediction models of the European
Centre for Medium Range Weather Forecasts and the United Kingdom Meteorological Office
received in the form of grid point values via the Global Telecommunication System.
Numerical weather prediction products are also routinely obtained from the Japan
Meteorological Agency (JMA). Products from these global models are generally adequate for
forecasting large-scale weather systems such as surges of the winter monsoon. However,
limited by the coarse resolution of the data received, the grid point information is
inadequate for resolving smaller scale features associated with inclement weather. To
fill this gap in numerical forecasting guidance, the Hong Kong Observatory runs an Operational Regional
Spectral Model (ORSM), which was adopted from the JMA, on a high speed computer. ORSM has a
resolution as high as 20 km and produces forecasts up to 48 hours. It provides better
support in very short-range forecasting. |
