Thunderstorm and Strong Wind Confirmation - Overview

Introduction

Thunderstorm confirmations are provided for major population centres in New South Wales, Queensland and Western Australia.  Strong wind confirmations are provided for major population centres in New South Wales.

The confirmations are displayed in monthly tables. Details of the periods covered are available for each State: NSW, QLD & WA.

This confirmation service is only accessible by Registered Users. For the general public and occasional users a similar fee-for-service facility is available. For details and for information on locations and time periods not provided in these reports please email us providing the post code and the name of the closest major town to your location of interest.

• NSW & ACT - ins.nsw@bom.gov.au
• Vic. - ins.vic@bom.gov.au
• QLD - ins.qld@bom.gov.au
• WA - ins.wa@bom.gov.au
• SA - ins.sa@bom.gov.au
• Tas. - ins.tas@bom.gov.au
• NT - ins.nt@bom.gov.au

General notes on thunderstorms:  

Lightning:

Thunder is the sound caused by the electrical discharge of lightning. Hence a thunderstorm is always associated with lightning.  

Rain:  

Often thunderstorms are associated with intense showers of rain, which can cause damage to property as a result of associated flash flooding, overflowing gutters, erosion, etc.

Hail:  

Hail is often a highly localised phenomenon, therefore not all occurrences are reported to the Bureau.
Damaging hail (on car bodies or roof tiles, for example) requires a size of about 2cm in diameter.
Smaller hail can also do damage to more sensitive objects or if the hail becomes deep and heavy.

Strong winds:  

Sustained winds (10 minute average wind speeds) above 50km/h are classified as strong, and along with short-term wind gusts above 90km/h, may cause damage to property. Topography and terrain may cause localised wind gusts, which are stronger than those detected by our sparse observation network.  

As our observation network utilises many stations that only record wind speeds on an hourly or three hourly basis, a strong wind gust could occur and not be recorded by the Bureau.  

Any thunderstorm can be associated with strong gusty winds caused by downdraughts within the storm. These downbursts can be relatively localised and as such not detected by our wind observation network.

Severe Thunderstorms:  

A severe thunderstorm is defined by the Bureau of Meteorology as one which produces:

• hail, diameter of 2 cm or more ($2 coin size); or
• wind gusts of 90 km/h or greater; or
• flash floods; or
• tornadoes, or any combination of these.

For further information on whether a particular storm was classified as severe please contact the relevant state's Climate Services Centre.

Information on 'Severe Storms - Facts, Warnings and Protection' can be found at: www.bom.gov.au/info/thunder/ 

Points to note when using this data for confirmations

• These thunderstorm reports are prepared regularly. The date of last update is found at the heading of each report.
• Daily reports of thunderstorm activity to midnight are updated as soon as possible following receipt of available data.
• In this analysis, all valid thunderstorm (and in some instances hail and strong wind) activity will be identified and reported. There may however be further reports received by us at a later date. These will be added retrospectively.
• It is possible, especially in the case of isolated thunderstorm activity, that some thunderstorms and/or hail are not detected because we have not received any reports of the storm event.
• If you have any doubt about the validity of the data, or you require a storm confirmation for a location other than those listed, please contact us. It may be possible for us perform a more thorough analysis to determine whether thunderstorms were likely. Before doing so, however, it may pay to recheck the reports for additions over past dates.
• Reports of hail, when available, are for any sized hailstones, regardless of the fact that they may have caused damage. Hail size reports are often estimated rather than measured and so may not be accurate. Queries relating to the size of hail should be directed to our Regional Office in the State concerned.

Other sources to Seek Help

The current supplier of Bureau of Meteorology lightning strike data is Global Positioning and Tracking Systems Pty. Ltd. (www.gpats.com.au/). Other companies offer similar services, such as Kattron (www.lightning.net.au/kattron.htm).

For further information about recent significant weather events in Australia please visit: www.bom.gov.au/inside/services_policy/public/sigwxsum/sigwmenu.shtml

 

Introduction | NSW | QLD | WA

 

Page updated:  February 2008