Brunei Darussalam will be transitioning from the inter-monsoon phase to southwest monsoon, expected to start by next month, according to the Brunei Darussalam Meteorological Department (BDMD).
Typically, the southwest monsoon will persist until September. During the southwest monsoon, atmospheric conditions over the country tend to be quite stable with minimal thunderstorms compared to the inter-monsoon period. The wind condition generally will be blowing from the Southwest direction during this period, the BDMD said.
The southwest monsoon is also synonym with the season of active development of tropical storm and typhoon systems over the northwest Pacific Ocean and the South China Sea. If this happens, the country’s weather could be influenced by the presence of tropical storm or typhoon systems. However, it depends on the intensity and distance of the locations from the country.
The influence of tropical storm or typhoon systems nearby the region may bring about the development of squall line phenomena causing the country to experience unsettled weather conditions with thunderstorms and occasional gusty winds. A squall line is fast-moving cells of thunderstorms in a long, narrow line formation. Meanwhile in August, dry weather conditions in the Southeast Asian region may cause the country to experience hazy conditions caused by transboundary haze from neighbouring countries as well as from local burning activities.
According to climatological data, the normal rainfall amount recorded at the Meteorological Observation Station at Brunei International Airport for June, July, August and September are 237.7 millimetres (mm), 241.8mm, 231.5mm and 235.1mm.
However, with reference to several international climate models, the rainfall amount for June is expected to be slightly above the normal value of 260mm which is between 290mm to 330mm, whereas for July and August will be above normal range which is above 340mm for July and above 320mm for August. The BDMD said while the normal amount of rain days in June, July and August is 17, for September it is 18 days.
