Status and Plans for Operational Tropical Cyclone Forecasting and Warning Systems in the North Indian Ocean Region - Monitoring and Prediction of Tropical Cyclones in the Indian Ocean and Climate Change - page 148

Fig. 1: (a) Average track forecast error (km) and (b) track forecast skill (%) of IMD
for TCs over the NIO during 2003-11 (Mohapatra et al., 2013).
The format and content of bulletins have been changed significantly
(Mohapatra et al., 2013). These improvements have contributed to effective
management of cyclone by disaster managers. The time of issue and frequency
of bulletins are standardized. The frequency of bulletin has also been increased
along with the increase in number of users. The lead time of the forecast has
been increased upto 72 hrs. The design of the bulletin has been revised with
inclusion of prognostic and diagnostic features, observed and forecast track
and intensity in tabular form and storm surge guidance for all member countries
of WMO/ESCAP panel. The observed and forecast track and intensity of the
cyclone are updated in cyclone page of IMD website time to time, based on the
tropical cyclone advisory bulletin. The cone of uncertainty in the forecast has
been introduced with effect from the cyclone, 'Ward' during December, 2009.
It is helpful to the decision makers as it indicates the standard forecast errors in
the forecast for different periods like 12, 24, 36, 48, 60 and 72 hrs. The examples
of track and intensity forecasts issued by IMD are shown in Fig. 2.
An example of the track forecast product during cyclone, Thane is shown
in Fig. 2. The balloon in the left figure shows the cone of uncertainty in track