The Hong Kong Observatory will expand the reference for issuing No. 3 and No. 8 typhoon signals, when this year's storm season starts.

In a Legislative Council paper today, the Observatory said a recent review of the present system prompted the switch to the new mechanism that works similarly to the rainstorm warning system.

Readings will now be taken from a network of eight wind-speed meters near sea level, covering all of Hong Kong.

The No. 3 or No. 8 signal will be issued when half or more of the meters register, or are expected to register, strong winds or gale- or storm-force winds.