During early boreal winter (northeast) monsoon (November and December), a series of cold air bursts out from intense Siberian highs towards the China coast in response to the development and movement of the 500 hPa trough. The resultant strong low level northwesterlies turn into northeasterlies across the South China Sea as “cold surges”. On interacting with the near-equatorial trough, mesoscale convective systems form north of the trough, giving rise normally to heavy downpours and severe floodings mainly along the coastal stretch in the east coast states of Peninsular Malaysia. In November 2014, one week-long episode of heavy downpour of more than 800 mm occurred along the coastal stretch of northeastern Peninsular Malaysia. However, in December 2014, two episodes of extreme rainfall occurred mostly over inland and mountainous areas of east coast of Peninsular Malaysia, in particular its northern sector. These two unusual events which lasted a total of 11 days with more than 1100 mm precipitation had resulted in extreme and widespread floodings as well as extensive damages in many inland areas. Analysis shows that the stronger wind surges from the South China Sea due to very intense cold air outbreaks of the Siberian high are under the ENSO-neutral condition. In addition, the developing mesoscale convective systems in the northeastern Indian Ocean (near northern Sumatra) in response to the propagation of a 500 hPa shortwave trough across the Indian Sub-Continent towards China were the combined factors for these unusual extreme rainfall and flooding events in the east coast of Peninsular Malaysia.