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Coastal Wind Warnings Service Change
In line with international standards the Bureau will introduce the terms 'storm force' and 'hurricane force' to describe wind conditions during extreme weather events that may affect coastal waters*, for example, in major tropical cyclones in the tropics or intense low pressure systems outside the tropics.
Warnings will be issued whenever strong winds, gales, storm force or hurricane force winds are expected.
* Generally out to 60 nautical miles from the coast
Example wind warning
In the tropics, hurricane force winds are associated with severe tropical cyclones (Category 3 and above). An illustration of a coastal waters wind warning incorporating the new terminology follows. Wave heights can be influenced by the size and movement of the weather system, shallow waters and proximity to the coast.
WARNINGS
FORECAST
(ILLUSTRATION PURPOSES ONLY)
Coastal waters wind warning
For waters between Wyndham and Kuri Bay
Issued at 5:00 am CST 31 January 2010
Synoptic situation
Severe Tropical Cyclone Xenon 952 hPa Located at
5 am CST near 12.5 S 125.2 E
Forecast at 4 pm CST 13.5S 124.6E
Hurricane force wind warning
Within 15 nautical miles of centre
Clockwise winds above 64 knots. Seas to 11 metres.
Storm force wind warning
Within 25 nautical miles of centre
Clockwise winds above 48 knots. Seas to 8 metres.
Gale warning
Within 50 nautical miles of centre
Clockwise winds above 34 knots. Seas to 5 metres.
Bureau wind warning categories |
|
 |
|
Strong wind Probable wave heights |
 |
Gale Probable wave heights |
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 |
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Storm force Probable wave heights |
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 |
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| Hurricane force 64 knots or more Probable wave heights around 11 metres* or more |
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Images courtesy Environment Canada
*Maximum waves may be up to twice the height.
Summary of wind warnings
| Old wind warning | New wind warning | Wind range* |
|---|---|---|
| Strong wind | Strong wind | 26 to 33 knots |
| Gale | Gale | 34 to 47 knots |
| Storm | Storm force | 48 to 63 knots |
| - | Hurricane force | 64 knots or more |
One knot = one nautical mile per hour = 1.85 kilometres per hour
* Ten-minute averages
Wind warnings for coastal waters attempt to provide around a 24-hour lead
time and are
normally renewed every six hours.
Please be aware wind gusts can be a further 40 per cent stronger than the
average and maximum waves may be up to twice the height.
1300 telephone numbers
Bureau weather warnings are available by 1300 services and are charged at
the cost of a local
call, more from mobile and public phones.
| Queensland | 1300 360 427 |
| New South Wales | 1300 659 218 |
| Victoria | 1300 659 217 |
| Tasmania | 1300 659 216 |
| South Australia | 1300 659 215 |
| Western Australia | 1300 659 223 |
| Northern Territory | 1300 659 214 |
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