Origin, Movement and Lifespan

TRS originate in latitudes between 5° & 20° and travel between W and WNW in the NH and between W and WSW in the SH, at a speed of about 12 knots. Somewhere along their track, they curve away from the equator – curve to N and then recurve to NE in the NH; curve to S and then recurve to SE in the SH.

Track – The route over which a TRS is already passed.
Path – The predicted route, over which, there is a possibility of the TRS passing shortly. Another point on the route is called the Vertex, which is the westernmost point, of the TRS, when recurving takes place.

The recurving is such that the storm travels around the oceanic high (which is situated at about 30°N and 30°S in the middle of large oceans). After recurving, the speed of travel increases to about 15 to 20 knots. Sometimes, a TRS does not curve or recurve at all but continues on its original path, crosses the coast, and dissipates quickly thereafter due to friction and lack of moisture. It is important to note that all TRSs do not follow such definite paths and speeds. In their initial stages, occasional storms have remained practically stationary or made small loops for as long as four days.