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 159

6. Bulletins and Products
6.1 Tropical Weather Outlook
Tropical Weather Outlook is issued daily at 0600 UTC based on 0300 UTC
observations in normal weather for use of the member countries of WMO/
ESCAP panel. This contains description of synoptic systems over NIO along
with information on significant cloud systems as seen in satellite imageries
and ridge line at 200 hPa level over Indian region. In addition, a special weather
outlook is issued at 1500 UTC based on 1200 UTC observations when a tropical
depression formed over north Indian Ocean. The special tropical outlook
indicates discussion on various diagnostic and prognostic parameters apart from
the 72 hours track and intensity forecast from the stage of deep depression.
The track and intensity forecast are issued for +06, +12, +18, +24, +36, +48,
+60 and +72 hours or till the system is likely to weaken into a low pressure
area. It also includes the description of current location and intensity, past
movement and description of satellite imageries. The time of issue of this
bulletin is HH+03 hours. The cone of uncertainty in the track forecast is also
included in the graphical presentation of the bulletin. Tropical weather outlooks
are transmitted to panel member countries through GTS and are also made
available on real time basis through internet at IMD's website.
6.2 Tropical Cyclone Advisories
Tropical cyclone advisory bulletin is issued when a deep depression intensifies
into a tropical cyclone (wind speed = 34 knots or more). It replaces the 'special
tropical weather outlook' bulletin. Tropical cyclone advisories are issued at
three hourly intervals based on 00, 03, 06, 09, 12, 15, 18 and 21 UTC
observations. The time of issue is HH+03 hrs. These bulletins contain the current
position and intensity, past movement, central pressure of the cyclone,
description of satellite imageries, cloud imageries, expected direction and speed
of movement, expected track and intensity of the system upto 72 hours like
that in special tropical weather outlook. The expected point and time of landfall,
forecast winds, squally weather and state of the sea in and around the system
are also mentioned. Storm surge guidance is provided in the bulletin as and
when required. Tropical cyclone advisories are transmitted to panel member
countries through GTS and are also made available on real time basis through
internet at IMD's website: http://www.imd.gov.in.
6.3 Tropical Cyclone Advisories for Aviation
TC advisories for aviation are issued for international aviation as soon as any
disturbance over the north Indian Ocean attains or is likely to attain the intensity
of cyclonic storm within next six hours. These bulletins are issued at six hourly
intervals based on 00, 06, 12 and 18 UTC synoptic charts and the time of issue