Severe Weather Warning Services assist the community in preparing for and responding to tropical cyclones, severe storms, bushfires and gales over land. These services are provided through the Bureau's State-based Regional Forecasting Centres (RFCs), with national coordination by the Head Office Weather and Ocean Services Policy Branch and very close links with State and Commonwealth emergency services and disaster preparedness organisations.

The Severe Weather Warning Service performed effectively during the year and contributed to a timely and well-organised community and emergency service response to severe weather situations. The number of weather warnings issued to the general public, together with the numbers of forecasts issued and weather enquiries received, is given in Table 9. The number of fire weather warnings far exceeded any total in the last five years, indicating the level of response demanded by the adverse seasonal conditions. The number of thunderstorm warnings was also significantly greater than in previous years. This is a reflection of the introduction of new systems and procedures for both monitoring and predicting severe storms.

Public access to severe weather warnings was improved significantly during 2002-03 with the full implementation of the suite of warnings available on 1300-prefix telephone numbers. This service now covers tropical cyclone advices, severe thunderstorm warnings, warnings of damaging winds and fire weather warnings (as well as other warnings with safety of human life implications such as road weather warnings, flood warnings and coastal waters warnings). There is a dedicated 1300 service for each State from which severe weather warnings can be accessed. In Western Australia, the Northern Territory and Queensland, there is an additional 1300 number for tropical cyclone advices. All 1300 services are updated automatically soon after the issue of text warnings, using the Bureau's text-to-speech conversion system. The services are available anywhere in Australia at any time at the cost of a local call. Table 9 shows that there were some 136,000 calls to this service during 2002-03. The radar imagery on the Bureau’s web site continued to be increasingly accessed as a source of information on rainfall and storms.

Another development in providing improved access to warnings was a three-month trial of the mobile phone Short Messaging Service (SMS) to deliver an alert to members of the public when a warning was issued. The trial covered four areas (Cairns, Gold Coast, Sydney and Perth). The results of the trial will be used to determine the potential for a mobile-phone-based service for the delivery of warnings.

Tropical Cyclone Warning Services
Tropical cyclone warning services are provided for northwest, north and northeast Australia, from Tropical Cyclone Warning Centres (TCWCs) co-located with the Perth, Darwin and Brisbane RFCs respectively. The planning and operation of the tropical cyclone warning service continued to be closely linked to, and coordinated with, the State Emergency Services in Western Australia, the Northern Territory and Queensland to maximise the effectiveness of community preparedness and response. New software was put in place across the nation, bringing improved and more nationally consistent TC threat-map products for the Bureau’s web-site. These threat map products are proving to be very popular with the public. The software also facilitates the use of multiple computer models to produce better forecast tracks using consensus techniques.

Eight tropical cyclones were observed in the Australian region during the 2002-03 tropical cyclone season, four of which crossed the Australian coastline, while another two moved close to the coast, influencing coastal communities. Although three of the cyclones in the Region were severe during their lifetimes, the maximum intensity of a cyclone when crossing the coast was category two (on a five point scale with five the most severe).

The Brisbane TCWC provided some support to the Solomon Islands Meteorological Service, which was incapacitated. This included the Brisbane TCWC providing some warning advices for Severe Tropical Cyclone Zoe to the Solomon Islands Broadcasting Corporation in late December. Zoe devastated some of the outlying islands of the Solomon Islands group. Improvements in the accuracy of the tropical cyclone warning service were assessed in terms of the decreasing errors in key forecast parameters, specifically the mean error in operational estimates of tropical cyclone position (Figure 31) and intensity as measured by central pressure (Figure 32). The mean errors of the current position, 12-hour and 24- hour forecast position and the central pressure estimates have continued to show a decreasing trend as a result of improvements in modeling and forecasting techniques.

Figure 31. Average errors in tropical cyclone location in the Australian region as compared with the post-event best estimates. The 00hrs plot shows the accuracy of real time estimation of the current cyclone position. The 12hrs and 24hrs plots show the accuracy of 12-hr and 24- hr forecasts. The straight lines show the long-term trend.		Figure 32. Average errors in tropical cyclone intensity (central pressure) in the Australian region as compared with the post-event best estimates. The 00hrs plot shows the accuracy of real time estimation of the current cyclone intensity. The 12hrs and 24hrs plots show the accuracy of 12- hr and 24-hr forecasts. The straight lines show the long-term trend.

	1998-99	1999-00	2000-01	2001-02	2002-03
WARNINGS
Strong wind warnings for small craft	5,647	7,035	8,288	7,238	8,898
Gale/storm warnings for shipping	2,885	3,444	5,391	5,197	3,705
Flood warnings	2,161	1,445	2,088	1,039	571
Fire weather warnings	70	248	341	378	1,234
Road weather alerts	232	387	593	405	466
Severe thunderstorm warnings	541	788	936	1,063	1,804
Sheep graziers alerts	161	181	308	371	240
Tropical cyclone warnings	448	1,306	1,144	375	366
Gale/storm wind warnings for land areas	337	244	302	364	500
Miscellaneous alerts (frost, brown rot, storm tide, etc.)	371	385	308	387	129
Total	12,853	15,462	19,699	16,817	17,913
FORECASTS
States, districts, cities, towns	303,003	206,648	218,066	175,628	144,617
Shipping, boating	90,399	121,850	127,716	101,730	103,273
Fire weather	31,099	15,255	10,258	9,336	8,783
Public utilities and other special interests	13,707	11,557	12,786	11,564	34,706
Extended period	78,724	104,359	81,372	80,647	14,566
Agricultural interests	2,948	1,521	1,135	1,903	1,183
Total	519,880	461,190	451,333	380,052	307,128
WEATHER ENQUIRIES
Enquiries (forecasts, current weather, climate etc.) - determined by sampling	802,673	949,801	900,617	812,096	749,293
Calls to recorded telephone forecasts (Dial It)	5,467,962	4,346,086	3,571,620	3,223,519	2,926,301*
Calls to recorded telephone service (1900)	724,720	516,183	374,238	318,219	302,461
Weather by Fax	1,682,860	1,129,692	782,306	557,940	432,992
Web hits (www.bom.gov.au)	5,268,176	8,651,540	12,925,700	16,801,400	23,534,437
Total	13,946,391	15,593,302	18,554,481	21,766,055	28,082,094
BASIC AVIATION AND WARNINGS
Aerodrome Forecasts	231,659	217,157	220,977	247,408	241,800
Aircraft altimeter settings needed for height above sea level (Area QNH)	47,020	32,829	26,945	24,204	21,450
Route Forecasts	9,608	6,690	5,704	4,444	7,247
Three-hour trend type forecasts	174,820	147,749	142,399	154,651	156,494
Area forecasts	36,719	30,204	28,245	26,533	32,604
Warnings (SIGMET, AIRMET, Airport Hazards)	2,799	2,401	1,991	1,923	3,566
Aerodrome Advices	2	26	19	218	124
Search and Rescue Services	132	73	65	45	74
Pilot Briefing Services	58,596	49,050	58,082	43,489	39,099
Pilot Documentation	12,103	8,008	5,583	5,034	4,456
Total	573,458	494,187	490,010	507,949	506,914

Figure 33. Warning and Advice areas under the Bureau's Severe Thunderstorm Warning
Service.

The Bureau is currently reviewing its warning services and is expected to extend severe thunderstorm warnings services across all of Australia in the near future, with more detailed services for the major capital cities assisted by newly developed automated thunderstorm tracking software.

Even with the benefit of continuous radar surveillance, it is difficult to monitor comprehensively the development, movement and intensity of severe thunderstorms. The national network of almost 3000 volunteer 'storm spotters' complements the radar network and continued to make a valuable contribution by monitoring, reporting and confirming occurrences of severe thunderstorms. Observations reported by storm spotters assisted forecasters with both the issue of warnings and the eventual verification of those warnings. The Bureau is continuing to refurbish and update its weather watch radar network, with the most significant improvements in 2002-03 being new radars at Canberra (Captains Flat) and Newcastle (replacing Williamtown). Plans to introduce Doppler facilities to six radars in coming years should greatly improve severe thunderstorm detection in the Southeast mainland capitals, Yarrawonga and Tamworth regions.

During 2002-03, there were 303 reports of severe thunderstorms across Australia and 1,028 warnings/advices issued, compared with 362 reports and 1063 warnings/ advices in the previous year.

The performance measures adopted for severe thunderstorm warnings are the Probability of Detection (POD), which is the proportion of correctly-warned severe thunderstorms (ideally 1; performance target 0.7 or greater), and the False Alarm Ratio (FAR), which is the proportion of ‘false alarm’ severe thunderstorm warnings (ideally 0; performance target 0.4 or less). The targets are based on an assessment of what is achievable using historical records of such statistics in both Australia and the US, but also taking into account an estimate of the accuracy needed for the warnings to be useful to the community. As illustrated in Figure 34, there is significant variation in the nationally averaged POD and FAR values over the nine-year record. The year-to-year variations reflect varying proportions of severe thunderstorms that occurred in capital cities for which the warning task is relatively difficult (e.g. Perth, Adelaide and Darwin) compared with the proportion that occurred in the other capital cities. In 2002- 03, the service was unable to achieve the targets set for the probability of detection or false alarm ratio. New initiatives with national guidance material together with the new radar upgrades should lead to an improvement in these performance measures.

The Bureau has maintained its 'average lead time' of warnings. A total of 68 severe thunderstorms was recorded in the metropolitan warning areas in 2002-03 and for the 29 for which warnings were issued, lead times ranged from one to 190 minutes. Over all events, with lead times of zero minutes allocated for missed events, the average lead time was 23 minutes, the same as for 2001-02.

Figure 34. Nationally-averaged values of Probability of Detection (POD -fraction of events for which advance warning was provided) and False Alarm Ratio (FAR - fraction of warnings which were false alarms) for the past ten years (1994-2003) for Severe Thunderstorm Warnings (all Australian capital cities except Canberra).

Fire Weather Warning Services
The fire weather warning service provides the public with routine forecasts of fire danger during the fire season and fire weather warnings when the fire danger is expected to exceed a certain critical level. It also provides fire management authorities, civil defence organisations, police and other emergency services with detailed routine forecasts, fire weather warnings and operational forecasts to assist in combating ongoing fires. This service includes special forecasts for hazard reduction burns and other advice to assist the assessment and management of fire risk and, where possible, out-posted support for fire control operations.

Clearly the most noteworthy events of the 2002-03 fire season were the prolonged and widespread bushfire outbreaks in the Australian Capital Territory, New South Wales and Victoria during December and January. These caused loss of life and considerable damage to property. As in the previous year, additional staff were seconded to the affected Regions from Queensland, South Australia, Tasmania and Head Office in order to cope with the additional workload. For the second year in succession, record numbers of special fire forecasts were issued, exceeding the record set last year by a considerable margin, with 2221 being issued in NSW and 1158 in Victoria.

A measure of the effectiveness of the fire weather warning service is the extent to which the community is accurately warned of severe events. Severe events in the fire weather context are those windy, hot and dry atmospheric conditions which, when combined with dry vegetation, constitute a high fire risk. Performance trends for fire weather warnings over the past ten years are shown in Figure 35 in terms of Probability of Detection (POD) and False Alarm Ratio (FAR). The challenge is to increase POD without increasing FAR. The figure shows that, during 2002-03, the previous downward trend in POD was reversed while maintaining the downward trend in FAR, albeit at a lesser rate. Thus the gap between POD and FAR was increased.

In delivering the Bureau's fire weather services, Regional Offices in each State and Territory continued their close collaboration and consultation with relevant fire and land management authorities through preseason planning meetings and post-season review meetings to ensure that, within an overall national policy framework, particular local issues were addressed. A theme across all fire agencies was the continuing need for assistance in the expert provision of fire weather training for fire agency staff. The Bureau continued to assist these activities during 2002-03 across several States, participating in a range of pre- and post-season courses. Service improvements introduced during the year included:

Destruction in Canberra in the aftermath of the severe fires in January.

• provision of satellite-derived grassland curing index data to fire agencies in Victoria and South Australia; and
• provision of forecasts of smoke concentration to assist in the deployment of airborne firefighting resources during the Victorian Alpine fires. Although developed primarily as a planning tool for prescribed burning operations, use of these products reduced the disruption to aircraft operations attributable to visibility reductions at the ground. Other significant activities during 2002- 03 aimed at contributing to the improvement of fire weather services included:
• very active participation in the successful proposal for the establishment of a Bushfire Cooperative Research Centre. The Bureau will be a major participant in the Centre which commences operation in 2003 for an initial seven-year period. This will enable fire control authorities to benefit from Bureau-led research into fire weather and Bureau services to improve through the application of findings from other areas of fire science;
• continued close collaboration and consultation nationally through the Bureau's Associate Membership of the Australasian Fire Authorities Council (AFAC), including participation in an AFAC-funded smoke management project; and
• attendance by Bureau staff at a range of conferences related to fire weather.