Real-Time Prediction of the Tropical Cyclogenesis Location over Bay of Bengal Using Global Forecast System (GFS) - Monitoring and Prediction of Tropical Cyclones in the Indian Ocean and Climate Change - page 292

5. Conclusion
NCEP-based GFS system has been in operational use at IMD New Delhi for
daily medium range forecasts. This paper assesses the skill of the GFS in
predicting the tropical cyclogenesis over BoB during summer monsoon 2011.
Case studies of monsoon depressions are illustrated to assess the ability of the
model to capture circulation features of summer monsoon. The GFS T574
model has a much stronger vortex at 120 hours than the GFS T382 model.
T574 showed considerable skill in predicting the tropical cyclogenesis location
over BoB. However, the accuracy in prediction of location and intensity of
cyclone fluctuates considerably. Using the GFS T574 operational products,
the genesis location can be predicted up to five to six days in advance with an
error less than 200 km, which can provide useful guidance for real-time
forecasting of tropical cyclones over BoB. Due to inaccurate location of low-
pressure systems by NWP models, in general, some mismatch prevails between
the spatial distribution of forecast heavy rainfall and the observed one. Because
of this double penalty, rainfall prediction skill deteriorates over Indian monsoon
region. The positional error of monsoon low pressure system could be further
reduced using a tropical cyclone relocation algorithm. Further improvement in
the forecast is expected with the possible inclusion of 3 Dimensional Hybrid
Ensemble KnF (Hamill et al., 2011) data assimilation and multiple physics in
the GFS.
Acknowledgements
Authors are grateful to the Director General of Meteorology, India
Meteorological Department for providing all facilities to carry out this research
work. Acknowledgements are due to NCEP, USA for providing the source
codes and support for the implementation of the upgraded Version GFS T574
at IMD. Authors acknowledge the use of TRMM Products of NASA, USA in
this work
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