Understanding the boating weather forecast
Transport Safety Victoria helps you interpret the weather warningsWind isn't a constant. Wind can change direction and strength very quickly, especially in Victorian waters and notorious Port Phillip Bay.
The following advice on weather forecasts, wind and wave warnings and trip preparation is offered by Transport Safety Victoria.
But no matter where you launch your boating escapades, it is important to understand the following 'univeral' terms when reading a weather report.
BOM WIND FORECASTS
The Bureau of Meteorology issues the following wind forecasts
>> Wind speed over the water is given in knots. When wind is mentioned in forecasts it refers to the average wind over a 10 minute period at a height of 10m.
>> Gusts are increases in wind speed lasting for just a few seconds. They typically range 30-40 per cent greater than the average wind speed.
>> Squalls are a sudden large increase in wind speed (usually accompanied by a change in wind direction) that lasts several minutes and then suddenly dies.
BOM WIND WARNINGS
The Bureau of Meteorology issues the following wind warnings
Strong wind warning: For winds averaging more than 25 knots and up to 33 knots
Gale warning: For winds averaging 34 knots and up to 47 knots
Storm warning: For winds averaging 48 knots or more
Transport Safety Victoria strongly advises operators of small craft not to go boating when any of the above weather warnings have been issued. The Bureau of Meteorology’s marine forecasts describe mean conditions over reasonably large areas such as Northern Bass Strait or Port Phillip. The same can be said for many open waterways around the country.
Meantime, reference to squalls and thunderstorms alerts vessel operators to adverse weather conditions expected for short periods of time within the forecast period. Therefore, forecasts may not reflect local conditions where topographic influences might channel or block wind and affect wave development.
Transport Safety Victoria says vessel operators should be familiar with local variations in certain wind streams before venturing out – ask the locals for advice. Many areas including waterways have microclimates and separate weather cells.
BOM WAVE HEIGHTS
The Bureau of Meteorology issues the following wave height warnings
As for wave heights, in forecasts these refer to significant wave height – being the average of the highest one third of waves. Larger waves do occur, especially in regions where tides and currents oppose wind-driven wave direction.
Large waves can be twice the significant forecast and prevailing wave height! Be aware of this fact, especially when crossing bars.
THUDERSTORM WARNING
Watch which way it is moving and make a run for it
Thunderstorms are also serious hazards for boats. Cumulonimbus or thunderstorm clouds produce strong, gusty winds, which blow out from the front of the storm. If you see this type of cloud, you should watch which way it is moving – clouds often move in different directions from the wind at the surface. If it looks like it will pass over or within a few kilometres of you, head for shore immediately.
>> Ensure you are carrying the prescribed safety equipment.
>> Ensure you wear a PFD where required and consider wearing a PFD at all times while operating a vessel.
>> Know the local factors that influence sea conditions and know where to reach shelter quickly.
>> Learn how to read the weather map.
>> Head to www.bom.gov.au for you latest local forecast. Be aware that the weather map in the morning newspaper was drawn the day before.
>> Always check the latest forecast and warnings before going to sea and know what conditions exceed your safety limits.
>> Beware of rapidly darkening and lowering cloud – squalls may be imminent.
>> When at sea, listen to the weather reports on public or marine radio.
>> Be flexible – change your plans if necessary.
>> Be prepared to head back to shore regardless of how far you have travelled.
>> Be prepared for changes in conditions and take warm clothing.
Always let someone know where you are going, your point of departure and when you plan to return. If your plans change, let someone know. Also give them a description or photo of your vessel, vessel registration number and details of the number of passengers on board. This will assist emergency services, should the need arise.
Download your trip details form and further good advice from the Recreational Boating Safety Handbook HERE from the Transport Safety Victoria website at Transport Safety Victoria or obtain a trip details fridge magnet from Transport Safety Victoria.
And, remember: If stranded on the water, stay with your boat.
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