Answer:
When any Public Storm Warning Signal Number is hoisted or put in effect for the first time, the corresponding meteorological conditions are not yet prevailing over the locality. This is because the purpose of the signal is to warn the impending occurrence of the given meteorological conditions. It must be noted also that the approximate lead time to expect the range of the wind speeds given for each signal number is valid only when the signal number is put in effect for the first time. Thus, the associated meteorological conditions are still expected in at least 36 hours when PSWS #1 is put in effect initially; in at least 24 hours with PSWS #2; in at least 18 hours with PSWS #3, in at least 12 hours with PSWS #4; and in at least 12 hours with PSWS #5. The lead time shortens correspondingly in the subsequent issues of the warning bulletin when the signal number remains in effect as the tropical cyclone comes closer.
Explanation:
