South Australia's improving weather services:
Frequently Asked Questions

What is changing?

City and Town Forecasts

District Forecasts

Marine Forecasts (updated 8/11/2011)

Notes on the Weather (updated 26/10/2011)


What is changing?

1. How does the new system work?

The Bureau of Meteorology is implementing a new forecasting system aimed at expanding and improving services to the South Australian public. The system allows the Bureau's forecasters to develop 7 day forecasts graphically, by "painting" the forecasts on their screen. Forecasters then save the information into a database which provides detail of the weather every 6km in a grid across the state.

The information stored in this database is then used to automatically generate text forecasts thereby enabling the Bureau to produce 7 day forecasts for many more locations than before.

The new system allows forecasters to input their local knowledge and account for important small scale phenomena not simulated in automated systems and thereby provide the best possible forecast for the community.

2. How will the forecasts change?

Forecasts produced by the new system will provide more detailed weather information including an expanded description of sunshine, cloud cover and rainfall, more detail about expected wind conditions, and greater clarity of expected temperatures.

Some forecasts will also be presented in a new format that combines text and graphics so they are more easily understood.

Forecast rainfall amounts and chance of rainfall for Adelaide City will be included on the Adelaide Metropolitan Day 1 forecast. In most situations this will relate to conditions across the larger metropolitan area.

3. Why doesn't my forecast print out on a single page?

Because of the extra detail included in the forecasts, some no longer fit on a single page.

If you have any issues with the new services, please send feedback.


City and Town Forecasts

4. Why doesn't my town receive a forecast?

With the launch of the new system the number of forecast locations for SA increases to 28 and now includes Glenelg. However, instead of just Adelaide receiving a 7-day forecast all 28 locations will receive a 7 day forecast.

Although Mount Barker previously was a forecast location it used to be part of the Adelaide Metropolitan forecast. Mount Barker will now receive its own 7-day forecast.

The list of official forecast locations will be reviewed next year and is likely to be increased. The additional locations will be selected based on population and geographical spread to provide a more equitable service across the state.

During 2012 we will also be providing graphical forecast maps on the South Australian Forecast Explorer. This map interface will allow you to find, display and zoom into your location and show you the weather details for any 6 x 6 kilometre square in South Australia. For a preview, test out the Victorian Forecast Explorer.

5. When are the forecasts issued?

All forecasts will be issued twice a day - at around 5am and just after 4pm. The Bureau's forecasters will also update forecasts promptly if conditions change unexpectedly. See the list of forecast issue times.

6. What does 'rainfall total' mean?

A forecast of rainfall amount, expressed as a range, is issued for Adelaide City. So forecasters can verify their forecast the rain gauge located in Kent Town is used to represent Adelaide City rainfall.

The forecast represents the likely rainfall range for the forecast period. Sometimes rain falls in a patchy pattern across an area with some locations receiving a heavy shower while an area nearby might miss out completely. On these days the rainfall range may be quite large, e.g. 5 to 30 mm. When steady rainfall is expected over a wide area, the range may be smaller, e.g. 10 to 15mm.

The locations that receive this information and the number of forecast days is likely to be expanded in 2012.

7. What does the 'chance of rain' mean?

The Adelaide City service also provides a "Chance of any rain" forecast. This describes the likelihood of receiving a measurable amount of rain (>0.2mm) during the day. For example, if the chance of rain for Adelaide City is 70%, it means that on 7 out of 10 days with similar weather conditions rainfall will be measured in the Kent Town rain gauge.

For instance, whilst there may be a 40% chance of rainfall, there is also a 60% chance of not receiving any rainfall at all.

The locations that receive this information, the number of forecast days and the number of forecast days is likely to be expanded in 2012.


District Forecasts

8. Why have some district boundaries changed?

There have only been minor changes to district boundaries. In the case of the northeast of the Mount Lofty Ranges the change has been done to better align with local council boundaries. There have also been some changes where boundaries have been changed to include entire conservation parks to assist with park management during the fire season. For instance, all of Ngarkat Conservation Park now lies within the Murraylands.

Although the changes are generally minor you will need to check which district you are in. See the map.

9. Why are there more District Forecasts?

There are actually the same numbers of districts but in the past we provided District Forecasts where we combined individual districts into the one product. For example; the Murray District forecast was a combination of the Murraylands and Riverland district forecasts. The new system allows us to provide separate districts forecasts. Since these districts are considerably smaller the new forecasts should be more detailed.

10. Why does my town forecast say the 'chance of a shower' but the broader district forecast does not mention rainfall?

The town forecasts are specific to a single location, whereas the district forecast describes the weather over a large area.

If rainfall is only forecast for a small part of a district it would not be mentioned as it might suggest that the entire district would receive rain when that is not the case.


Marine Forecasts (updated 8/11/2011)

11. Why is the wind information in the written forecast sometimes different to the 'Forecast Wind for Marine Areas' maps?

The state-wide wind forecast maps are automatically produced from computer models and may not always be the same as official forecasts which contain input from a professional forecaster. These differences will be seen most often when there are weather fronts, east coast lows, sea breezes or in rapidly changing conditions. If you use the maps you should also check the official forecasts and warnings.

During 2012 there will be official wind and wave forecast maps provided via the Forecast Explorer. For a preview, test out the Victorian Forecast Explorer.

12. Where can I find information about wind warnings?

Wind warnings are now issued as part of the Coastal Waters Forecast. The Bureau now issues wind warnings for today and tomorrow, rather than a rolling 24 hour period. Wind warning labels will be added alongside the forecast for today and tomorrow to clearly indicate if warnings have been issued for each day.

A separate ‘Marine Wind Warning Summary’ for South Australia will list the zones with warnings for today and tomorrow, grouped by each warning category. Since this is a summary product you will need to go direct to the appropriate Coastal Waters Forecast for details about the winds, seas and swell.

For more information please see the Wind Warning Changes [PDF, 204Kb].

13. What happened to the Coastal Waters forecast with all the zones in it?

There are now 10 Coastal Waters Zones; Far West Coast, Upper West Coast, Lower West Coast, Central Coast, South Central Coast, Spencer Gulf, St. Vincents Gulf, Investigator Strait, Upper South East Coast, Lower South East Coast.

Since there are now many more zones, putting all the information in the one product is not viable. You should refer to the forecast for your particular area(s) of interest.

The smaller zones allow more detailed forecasts to be written and each coastal zone forecast will have an improved layout for easier reading. You will also be able to select the forecast you need through an interactive map.

14. Why has the Adelaide Metropolitan Waters, Goolwa and adjoining lakes been changed?

The original Adelaide Metropolitan Waters, Goolwa and adjoining lakes forecast was a great innovation and one of the Bureau's first efforts at producing graphical and tabular information. The forecast was an addition to the standard written coastal waters forecasts.

The Next Generation Forecast and Warning System was introduced for SA on 26 October with many new forecasts and formats of written forecasts but the initial implementation is largely free of graphical or tabular services. The only exception to this is our revamped Adelaide Metropolitan Waters, Goolwa and adjoining lakes forecast since we understand how important this service is to marine users. The new service is not an exact replica so it may take some time to get used to and it does not yet contain tables of forecast information.

The new service may be more complex but there are great advantages with the extra detail. It provides 3 hourly forecasts out to 72 hours ahead and often the peak of sea breezes or gully winds were missed under the old system. In the past there were only a few sites such as Outer Harbor (Black Pole) available. If you look at the image below you can see that under the old service the Outer Harbor forecast would have been 10-15 knots, but the new service lets you see that if you were tracking from the the Port River to Black Pole you would likely be affected by winds of 15- 20 knots and in excess of 20 knots close to St Kilda.

Adelaide Metropolitan Waters, Goolwa and adjoining lakes

 


Notes on the Weather (updated 26/10/2011)

15. Where has the Notes on the weather gone?

The notes on the weather product has been discontinued. It has been replaced by two different products:



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