The two main monsoon seasons in Malaysia are the Northeast Monsoon and the Southwest Monsoon Season. In between the two monsoon there are two short inter-monsoon periods which are the Pre South-West Monsoon and Pre North-East Monsoon. The monsoon that affects the living of the Peninsular Malaysia east coast, particularly those in the fishing industry is mainly the Northeast Monsoon which will bring strong wind and rainfall from November to January.
Northeast Monsoon season is characterized by constant winds that blow from the northeast. It is associated with the development of the Siberian High which is a massive collection of cold dry air on the Eurasian terrain and the movement of the heating maxima from the Northern Hemisphere to the Southern Hemisphere. Northeasterly winds flow down Southeast Asia with wind speeds reaching as high as 30 to 40 km/hr.
Rough sea in NE monsoon season even after sheltered by the Seribuat Island
During the season, the states in the east coast of Peninsular Malaysia, coastal areas of Sarawak and Sabah will experience episodes of heavy rain continued for a total of two to three days due to monsoon surges. In the case of extreme weather,the whole episode of heavy rain can last for three to eight days, and may cause flood. However, there are usually several days of good weather that is either with no rain or little rain that occur between the heavy rainfall episodes.
The northeast monsoon causes most of the Peninsular east coast fishermen not able to continue fishing. Many fishermen will start to face with monetary issues and turn to the middleman for loan. The fisherman in Tanjung Leman is a little more lucky because their fishing area is located behind the Seribuat islands. There are some days that strong wind and thunderstorm will disrupt their fishing routine but they will still be able to fish during the season.
Highly sought after Yellow Croaker or Gelama Mas in Malay
The monsoon season also changes the species of fish caught by the fishermen in the east coast. During the beginning of the season, fish species from the mackerel and threadfin family will be abundant. The highly sought after Yellow Croaker that is gold in color is one of the species that can only be found during Northeast Monsoon. Spiny lobster will also move in nearer to shore and become abundant. Grouper on another hand will become scarce as they move further out into the sea.
Southern Winds and Inter-monsoon
Southwest Monsoon season in Peninsular Malaysia is characterized by winds that blow from the southwest starting from late May to September. It is associated with the rise of temperature in the Asian continent and the temperature drop in the southern hemisphere. In the southern hemisphere the wind blows from Southeast direction and changes direction to southwest as it passes the equator. This effect is called the Coriolis Effect which is caused by the rotation of the earth.
During the southwest monsoon period, rainfall in the Peninsular Malaysia will reduce as rainfall in the western Sumatra peaks when the monsoon wind passes through the Barisan Mountains, a mountain range on the western side of Sumatra.
Calm sea during the SW monsoon in the east coast of Peninsular Malaysia
Sumatra Squalls or Ribut Sumatra are thunderstorms which usually occur from April to May and from September to October each year during the inter-monsoon periods. These squalls develop at night over Sumatra or the Straits of Malacca and move east toward Peninsular Malaysia usually during dawn and early morning. Squall are characterized by sudden onset of strong gusty winds of up to 100 km/hour and heavy rain to the southwestern part of Peninsular Malaysia starting from the state of Selangor to Johor.
Sea breezes are common during the inter-monsoon and southwest monsoon season. The winds are formed as a result of temperature differences between land and sea. In the day, land gets heated rapidly by the sun while sea surface temperature increases less. When hot air rises over the land, cool air just above the sea moves inland to fill the void and circulate back to sea higher above. Sea breezes and opposing light constant wind can sometimes initiate thunderstorm that usually align with the coastline.
Waterspout is rare in Peninsular Malaysia but if it happens usually will be in the inter-monsoon periods. Waterspout occur during intense weather condition associated with thunderstorm and often being mistaken as a tornado due to the similar appearance. Unlike tornado that can occur over both land and sea, waterspout only forms over the sea. It usually dissipate on reaching the coast.
Waterspout in Tanjung Leman
From April onward, the east coast of Peninsular Malaysia sea will start to calm down. Fish species like grouper, snapper, wrasse and sweetlips will move closser to the shore. Good time for fishing will be back for anglers until October.
Grouper is abundant in Tanjung leman during the SW monsoon