Weather information updated hourly
WE were very pleased to see that the writer of the letter headlined, ''More regular reports plea'', (South China Morning Post, June 8), has been using Hong Kong Telecom's INFOFAX service to obtain weather information.
This service is indeed a convenient and inexpensive means of acquiring weather forecasts and reports by fax.
However, the fax numbers quoted in his letter are only part of the INFOFAX weather services. His requirements indeed can be better served by other fax numbers.
For weather forecasts and temperature readings within the territory of Hong Kong, the fax numbers to call should be 177 2001 (English) and 177 2733 (Chinese). Information from these fax numbers is updated hourly.
In the case of a tropical cyclone threatening Hong Kong and necessitating the hoisting of tropical cyclone warning signals, positions of the storm are given every hour to a precision of 0.1 degrees in latitude and longitude. This should allow keen weather watchers to track tropical cyclones with sufficient accuracy.
The weather map referred to in the letter is prepared based on essentially three-hourly synoptic observations collected from vast areas in the region.
As such it takes a long time to prepare and be made available from 177 2002. This is not the best means for tracking tropical cyclones.
The weather bulletin from fax number 177 2755 is titled ''Weather Information for South China Coastal Waters.'' The primary purpose of this bulletin is to serve the fishing and yachting communities who venture beyond the boundaries of Hong Kong waters, and the use of wind force in Beaufort scale is to meet their requirements.
For the general public, 177 2001 and 177 2733 contain general wind forecasts using descriptive terms, such as ''light'', ''moderate'', ''fresh'', ''strong'' etc, that should relate to everyday experience.
Y. K. CHAN Ag. Assistant Director (Forecasting and Warning Services) for Director of the Royal Observatory