Changes in Bass Strait

  During late October mariners would have noticed some changes to the Victorian marine forecasts and warnings provided by the Bureau of Meteorology.
  There will be an extra forecast zone in Bass Strait. The current Victorian East Coast zone that extends from Wilson’s Promontory to Gabo Island will be divided into two new zones.
  These new zones are ‘Central Gippsland Coast – Wilson’s Promontory to Lakes Entrance’ and ‘East Gippsland Coast – Lakes Entrance to Gabo Island’.
  The two new zones will allow more detailed forecasts for the individual zone. This will be especially true with the timings of slow moving cold fronts transiting the two zones.
  Port Phillip Bay and Westernport Bay forecasts that are currently issued together will be separated and issued individually.
  There are also several changes to warnings in the Victorian coastal zones.
  The warnings will be succinct and will highlight the worst conditions expected within the next 24 hours. The warnings will focus on the highest winds and highest waves expected in a designated area. Note that these highest winds are averages and do not include gusts.
  The warnings will also contain the ‘Combined sea and swell’ wave height instead of the existing separate sea and swell information. This combined height will be indicative of the conditions actually experienced (a mixture of sea and swell) by the mariner. This combined height is the significant combined height; maximum combined waves may be twice this height.  It is important that mariners are aware of the contribution that both sea (wind waves) and swell make to the combined wave height (see Afloat, April’08).  The Victorian Coastal Waters Forecast will still have separate sea and swell forecasts. Mariners should check this forecast to see the differing contribution that both sea and swell are making to the combined wave height.
  Mariners who will be crossing into Victorian coastal waters from adjacent coastal waters (SA, NSW, TAS) will need to be aware of the different format of the warnings between coastal waters. The adjacent coastal water will remain in the same format, that is individual sea (wind waves) and swell waves.
  Yachts in this year’s Sydney to Hobart will pass through the Victorian zones and will need to understand these changes.
  See http://www.bom.gov.au/marine/about/servicechanges/ vic-services-2008.shtml

*Malcolm Riley is the Public and Marine Officer for the Bureau of Meteorology in Hobart. He has worked in all States with the exception of QLD and is a Master V. He gives education courses on Marine Meteorology.