Some do not even have spiral bandings to give clues to the possible circulation centre. In poorly organized storms, there can be strong asymmetry and irregularity in the horizontal structure as well as distortion in the vertical alignment. The tell-tale spiral features which define the circulation centre are much better depicted in the visible version. Visible imageries, not available at night in the absence of sunlight, will be sorely missed by night forecasters in situations like this. Another problem related to Hong Kong concerns its geographical setting.
Most tropical cyclones approach the coast of southern China on a west-northwestward track.
With the orientation of the coastline at such an oblique angle to the storm track and Hong Kong being such a small target, a deviation of only 10 degrees in the direction of storm movement is enough to divert the storm to Hainan Island instead of a direct hit on Hong Kong. A mere difference of 10 degrees in the direction of movement can result in contrasting weather scenarios in Hong Kong. Faced with an uncertain and ever-changing situation, forecasters need to keep a close watch and be prepared to make timely updates and intelligent decisions. By the same token, the public should be aware of the uncertainties involved and be prepared to respond to the latest development as indicated by the warning bulletins.