TCEWS

Tropical Cyclone Early Warning System (TCEWS) provides information on the development of cyclone and forecasts the category of cyclone as well as level of threat for the people live along the coastal zone. Coastal flooding risk associated to tropical cyclones is nowadays a major concern in low-lying and populated areas in Oman. In the past few years there have been devastating examples in the Arabian Sea (i.e. Gonu or Phet). For this, the system is designed to determine the maximum water levels along the coast and predicts the flood levels.  Seasonality of tropical cyclone is one of the tools added to the system in order to give the probability of their occurrence during the cyclone seasons.

Components of TCEWS

TCEWS consists of monitoring the cyclone using satellite images from different satellite missions such as Jason, GEOS_7, and GEOS_10, and collecting meteorological data from various stations. Moreover, running numerical models is an important role in order to predict cyclone track and associated storm surge. Also, the TCEWS is supported by the historical data of the previous events for the comparison of the upcoming event.

Products of TCEWS

The cyclone is forecasted from the indication of depression and its development to be tropical until the stage is clear as cyclone. The message to the stakeholders will be issued when the stage of depression or storm is also clear.  The track of cyclone will be also modelled and compared with other modelers for validation purposes. The bulletin of messages is issued from time to time to update the current status of cyclone, either a depression, storm, or cyclone with some categories. Depending on the maximum sustained wind speed, tropical cyclones will be designated as follows:

It is a tropical depression when the maximum sustained wind speed is less than 63 km/h (34 knots). It is a tropical storm when the maximum sustained wind speed is more than 63 km/h (34 knots). It is then also given a name. Depending on the ocean basins, it is designated either a hurricane, typhoon, severe tropical cyclone, severe cyclonic storm or tropical cyclone when the maximum sustained wind speed is more than 119 km/h (64 knots).

Tropical cyclones can be hundreds of kilometers wide and can bring destructive high winds, torrential rain, storm surge and occasionally tornadoes. According to the Saffir-Simpson Hurricane Wind Scale, the hurricane strength varies from Category 1 to 5:

• Category 1 hurricane is referring to the hurricane with maximum sustained wind speeds of 119-153 km/h.
• Category 2 hurricane is referring to the hurricane with maximum sustained wind speeds of 154-177 km/h.
• Category 3 hurricane is referring to the hurricane with maximum sustained wind speeds of 178-209 km/h.
• Category 4 hurricane is referring to the hurricane with maximum sustained wind speeds of 210-249 km/h.
• Category 5 hurricane is referring to the hurricane with maximum sustained wind speeds exceeding 249 km/h.