Pagasa updates tropical cyclone classification system

/ 04:09 PM May 20, 2015

SIGNAL No. 5 is now part of the state weather bureau’s public storm warnings.

Dr. Vicente Malano, the Philippine Atmospheric Geophysical and Astronomical Services Administration’s acting administrator, noted that for the past 10 years, the Philippines has experienced a number of extremely damaging tropical cyclones.


Public Storm Warning Signal No. 5 is for typhoons with more than 220 kilometers per hour of wind speed, which is also the same as Super Typhoons.

The new public storm warning signal system, signed last May 18, is as  follows:


PSWS No. 1 – tropical cyclone winds of 30-60 kph are expected within the next 36 hours

PSWS No. 2
– tropical cyclone winds of 61-120 kph are expected within the next 24 hours
PSWS No. 3 – tropical cyclone winds of 121-170 kph are expected within the next 18 hours
PSWS No. 4 – tropical cyclone winds of 171-220 kph are expected within the next 12 hours
PSWS No. 5 – tropical cyclone winds of more than 220 kph are expected within 12 hours

The weather bureau also updated its tropical cyclone classification system.

Effective May 1 this year, the new tropical cyclone categories are:

Tropical Depression — a tropical cyclone with maximum sustained winds of up to 61 kilometers per hour or less than 33 nautical miles per hour (knots).

Tropical Storm — a tropical cyclone with maximum wind speed of 62 to 88 kph or 34-47 knots.

Severe Tropical Storm — a tropical cyclone with maximum  wind speed of 89 to 117 kph or 48 – 63 knots.


Typhoon — a tropical cyclone with maximum wind speed of 118 to 220 kph or 64-120 knots.

Super Typhoon — a tropical cyclone with maximum wind speed exceeding 220 kph or more than 120 knots.

Rene Paciente, weather forecaster from Pagasa, said this is the first time they will officially include the Severe Tropical Storm and Super Typhoon categories in the public storm warning list.

The Severe Tropical Storm has long been used in shipping advisories but not in weather bulletins. The Super Typhoon, meanwhile, has been used in recent times but was not officially a cyclone category then, he said.

He said these new categories have been included to adjust to the changing times. AC

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