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 155

in the vertical. The latest version of NCEP HWRF was also implemented at
IMD in 2012 for the Indian basins with the assimilation of local observations.
The model has the provision for vortex re-location and moving nesting
procedure. The model has special features coupled with Ocean model to take
into account the changes in SST during the model integration.
In these runs only the atmospheric model (HWRF) has been tested. The
Ocean Model (POM-TC) and Ocean coupler requires the customization of
Ocean Model for Indian seas. In this regard, work is in progress in collaboration
with INCOIS, Hyderabad which is running the Ocean models (POM)/Hybrid
co-ordinate ocean model (HYCOM) with Indian Ocean climatology and real
time data of SST over Indian seas. The model uses IMD GFS-T574L64 analysis/
forecast as first guess and, based on 00 UTC and 12 UTC initial conditions,
provides six hourly track and intensity forecasts valid up to 72 hours. The
QLM, a multilevel fine-mesh primitive equation model with a horizontal
resolution of 40 km and 16 sigma levels in the vertical, is being used for tropical
cyclone track prediction in IMD. The initial fields and lateral boundary
conditions are taken from the IMD GFS T574L64. The model is run twice a
day based on 00 UTC and 12 UTC initial conditions to provide six hourly
track forecasts valid up to 72 hours. The track forecast products are disseminated
as a World Weather Watch (WWW) activity of RSMC, New Delhi.
The multi model ensemble (MME) technique (Kotal and Roy Bhowmik,
2011) is based on a statistical linear regression approach and is used to generate
forecasts based on member models, WRF(ARW), QLM, GFS(IMD),
GFS(NCEP), ECMWF and JMA. All these NWP products are routinely made
available in real time on the IMD web site www.imd.gov.in.
As part of WMO programme to provide a guidance of tropical cyclone
(TC) forecasts in near real-time for the ESCAP/WMO member countries based
on the TIGGE Cyclone XML (CXML) data, IMD implemented JMA supported
software for real-time TC forecast over North Indian Ocean (NIO) during 2011.
The ensemble and deterministic forecast products from ECMWF (50+1
members), NCEP (20+1 Members), UKMO (23+1 Members) and MSC (20+1
Members) are available near real-time for NIO region for named TCs. These
products include: Deterministic and Ensemble TC track forecasts, Strike
Probability Maps, and Strike probability of cities within the range of 120 kms
four days in advance. The JMA provided software to prepare Web page to
provide guidance of tropical cyclone forecasts in near real-time for the ESCAP/
WMO committee members. The forecast products are made available in real
time. An example of these products is shown in Fig. 5.
In NCMRWF the global ensemble forecasting system (GEFS) configuration
consists of four cycles corresponding to 00Z, 06Z, 12Z and 18Z and 10-day
forecasts are made using the 00Z initial condition. Probabilistic forecasts of
quantitative precipitation are also generated based on NCMRWF-GEFS. In
these charts, the probability that 24-hour precipitation amounts over a 2.5 ×
2.5 lat-lon grid box will exceed certain threshold values is given. The forecast