Overview

This case study focuses on a potential fog event in Melbourne, Australia, on 6-7 April 2008. The key aim of this module is to step through the forecast process during a potential fog event from the perspective of an aviation forecaster with the Bureau of Meteorology. This involves consideration of model guidance and observations, identification of potential areas of fog, nowcasting, forecasting fog clearance, and providing TAF updates throughout.

This case is presented in three main parts:

  1. A Case Profile which introduces the case setting and the current forecast.
  2. A Case Challenge consisting of a series of forecast questions focused on three key time points in the case.
  3. A Case Summary with a brief analysis of how the case unfolded.

Geographic Location: Melbourne, Australia

Case Time Frame: 6-7 April 2008

Time Zone: Australian Eastern Time (EST) = UTC + 10 hours.

Phenomenon of Interest: Potential fog impacting on local and international aerodromes.

Forecasting Challenges:

  • Forecast the fog potential and classification for the Melbourne region over the next 24 hour period including: forecasting fog onset time and the associated reduction in visibility; forecasting the duration of the fog and fog clearance times at local airports.

  • Monitoring for fog risk as the night progresses and updating forecast parameters as necessary.

  • If fog and low-cloud have formed, identify areas of fog and low-cloud. Determine the fog and low-cloud onset, associated reductions in visibility, duration and clearance times at airports in the Melbourne area based on identifying processes that will lead to further radiational cooling and/or advection of existing areas of fog/low cloud.

  • The forecast process involves integrating all observations, satellite imagery, NWP and official forecast products to forecast and nowcast the basic ingredients required for fog and low-cloud formation and involve: assessment of the synoptic weather considerations; assessment of the mesoscale and local influences; assessment of the regional and local fog climatology.