Tropical Cyclone Wind Signals
Weather alerts in the Philippines / From Wikipedia, the free encyclopedia
The Tropical Cyclone Wind Signals (TCWS, or simply wind signals or signals;[lower-alpha 1] Filipino: Mga Babala ng Bagyo) are tropical cyclone alert levels issued by the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) to areas within the Philippines that may be affected by tropical cyclone winds and their associated hazards.[1]
PAGASA's TCWS system is activated when a tropical cyclone is inside or near the Philippine Area of Responsibility and is forecast to affect the Philippine archipelago. It is a tiered system that has five numbered levels, with higher numbers associated with higher wind speeds and shorter "lead times", which are time periods within which an expected range of wind strength is expected to occur.[1][2][3] TCWS signals are issued for specific localities (province or city/municipal level) and are escalated, de-escalated or lifted depending on the expected strength of winds and the movement of the tropical cyclone relative to the affected areas.[4][1]
The TCWS system is the consequence of decades of evolution of early warning systems for tropical cyclones in the Philippines. The very first tropical cyclone warning in the country was issued in July 1879, albeit it was in 1931 when the earliest formalized system of tropical cyclone warning was implemented by PAGASA's predecessor, the Philippine Weather Bureau.[5] In the late 20th century, this system gradually transformed into the more familiar four-tiered public storm warning signal system.[6] This was further subject to revisions after the catastrophic onslaught of Typhoon Haiyan (Yolanda) in 2013, which prompted the addition of a fifth warning level to emphasize extreme tropical cyclone winds.[7][8] The current version of the TCWS was implemented in 2022.[9][10][11]