Bureau of Meteorology Tropical Cyclone Forecast Track Map

Trial product description

Western Australia

NOTE THIS IS A TRIAL PRODUCT SUBJECT TO MODIFICATIONS AT SHORT NOTICE
 

The Bureau of Meteorology is introducing a new graphical product for the 2005 / 06 Tropical Cyclone Season.  This product will provide a map displaying the forecast positions of the centre of a tropical cyclone up to 24 hours ahead - as well as the lastest observed location of the tropical cyclone and its destructive winds. The product will be similar in style to the existing tropical cyclone threat map.  It will be available on the Bureau's public web site at http://www.bom.gov.au/

This product will not contain all the information available in the text forecast, particularly important impact information like the often most dangerous threat of storm tide.  It should be viewed as an illustration with the text product.

There will be some small differences in the product between regions.  This page describes the product for Western Australia.  Note this is the same as the corresponding product for Northern Territory and all of the Gulf of Carpentaria and slightly different from the east coast of Queensland.


Description of image

For the tropical cyclone the product image will shown the following:

The latest observed position is indicated in blue. The number in the circle shows the latest observed intensity category. Next to the circle will be the time and date of the latest observation.

Wind Zones

The solid coloured areas around the observed cyclone position represents the area affected by winds represented by that colour.

Wind Categories:  Gusts (km/h) Typical Impacts (not including rain, flood and storm surge)
Gale Force* Less than 125 Negligible house damage.
Damage to some crops, trees and caravans.
Craft may drag moorings.
Destructive 125 to 170 Minor house damage. 
Significant damage to signs, trees and caravans.
Heavy damage to some crops.
Risk of power failure.
Small craft may break moorings.
Very Destructive More than 170 Significant damage to structures.
Caravans destroyed.
Dangerous airborne debris.
Power failure likely.


Official Forecast Track

This is the forecast track which indicates the most likely path expected for the cyclone. The 12 hour and 24 hour forecast positions for the cyclone centre are marked along the path as black circles.
The numbers in the circles at these centre locations show the forecast intensity category. If the system is expected to weaken an "L" will be used to indicate a low pressure centre.

The rings represent the forecast outer extent of each category of wind strength, that is assuming the cyclone follows the official forecast track. Ring colours match the wind zone colours described above. The winds are likely to extend beyond these areas as the cyclone will almost certainly not follow the forecast track exactly. The extent of the warning and watch zones reflects this fact.

Note that the rings may be omitted for the 12 hour and 24 hour forecast positions to minimise clutter in the image.

Grey Zone of Uncertainty

The grey zone indicates the area within which the cyclone centre is expected to be in the 24 hours after the latest observed time. This covers most scenarios but on some occasions the cyclone may move beyond this area.

A cyclone is more than its centre, and its impact will almost certainly extend well beyond this zone.


Warning / Watch Zones

The dark orange shows the area where a Tropical Cyclone Warning is current; that is land areas that are expected to experience gales within 24 hours

The light orange shows the area where a Tropical Cyclone Watch is current; that is land areas that are expected to experience gales within 48 hours, but not within 24 hours.

Note
For WA, NT and all Gulf of Carpentaria communities, the outer ring is the extent of gales: mean wind 62 km/h (34knots) or greater. For the east coast of Queensland the outer ring is the extent of strong gales: 75 km/h (41knots) or greater. 

Those maps have a distinctive colour scheme.
Note: Mariners should check relevant marine warnings for the full extent of gales and strong winds.

Links

WA graphical TC forecast
NT + Gulf of Carpentaria graphical TC forecast
East Coast graphical TC forecast
Surviving Cyclones

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Latest Version: October 2005