TROPICAL CYCLONE trajectory forecast
ECMWF Tropical cyclone forecast products are designed to provide
both high resolution and probabilistic information on movement and
intensity of individual tropical cyclones. The system is vitally
dependent on observations from various tropical cyclone centres
around the world. In other words, the TC forecasts does not take
genesis into account - TCs can however die in the process if they
are not forecasted to stay strong enough.
Once observations are available, the movement of
a TC is automatically tracked, both in the high resolution and the
ENS forecasts. The tracking algorithm is based on extrapolation of
past movement and the mid-tropospheric steering flow to obtain a
first guess position. The actual position is determined by
searching for MSLP and 850 hPa vorticity extremes around the first
guess position. Also thickness maximum, wind speed and orography
are evaluated. More details can be found in the following Tech.
Tropical cyclone products are presented in the FM 94-IX Ext. BUFR
Tropical Cyclone products are disseminated
separately from other high resolution forecast products and have
their own dissemination schedule (Table 4.12 below).