Explanation:
TROPICAL STORM (TS) - a tropical cyclone with maximum wind speed of 62 to 88 kph or 34 - 47 knots.
SEVERE TROPICAL STORM (STS) - a tropical cyclone with maximum wind speed of 89 to 117 kph or 48 - 63 knots.
TYPHOON (TY) - a tropical cyclone with maximum wind speed of 118 to 220 kph or 64 - 120 knots.
HURRICANE - to be considered a hurricane, the storm wind must reach speeds greater than 74 mph (119.09 km/h).
TROPICAL DEPRESSION is a tropical cyclone that has maximum sustained surface winds (one-minute average) of 38 mph (33 knots) or less.
