revised definition of super typhoon, signal system. An area having a storm signal may be under: TCWS #1 – Tropical cyclone winds of to are expected within the next 36 hours. (Note: If a tropical cyclone forms very close to the area, then a shorter lead time is seen on the warning bulletin.) TCWS #2 – Tropical cyclone winds of to are expected within the next 24 hours. TCWS #3 – Tropical cyclone winds of to are expected within the next 18 hours. TCWS #4 – Tropical cyclone winds of to are expected within 12 hours. TCWS #5 – Tropical cyclone winds of or greater are expected within 12 hours. These tropical cyclone warning signals are usually raised when an area (in the Philippines only) is about to be hit by a tropical cyclone. As a tropical cyclone gains strength and/or gets nearer to an area having a storm signal, the warning may be upgraded to a higher one in that particular area (e.g. a signal No. 1 warning for an area may be increased to signal #3). Conversely, as a tropical cyclone weakens and/or gets farther to an area, it may be downgraded to a lower signal or may be lifted (that is, an area will have no storm signal). Classes for preschool are canceled when signal No. 1 is in effect. Elementary and high school classes and below are canceled under signal No. 2 and classes for colleges, universities and below are canceled under signal Nos. 3, 4 and 5. List of Philippine typhoons Pre–1963 The JTWC was already naming tropical cyclones in the Northwest Pacific basin since 1945, before the Philippines did so. Only a few notable storms persisted before 1963. A tropical cyclone assumably impacted Northern Luzon in July 1911, in which a record-breaking precipitation level was seen in Baguio, with of rainfall being dumped by the storm. In November 1912, a typhoon swept through the central Philippines and "practically destroyed" Tacloban. In Tacloban and Capiz on the island of Panay, the death toll was 15,000, half the population of those cities at the time. In 1881, a typhoon also impacted Northern Luzon, but around 20,000 people have died from the typhoon, making it the deadliest Philippine typhoon in recorded history. 1963–1999 In 1963, the PAGASA began naming tropical cyclones that enter their area of responsibility using female names ending with "ng". During the period 1963