About North-East monsoon

The Northeast Monsoon

One of the great seasonal wind shifts is that of East and Southeast Asia between the height of summer and the end of fall. Whereas summer`s winds tend to blow from the south and west, those of mid to late fall, on the other hand, waft in from the north and east, especially from central China to Indochina. This shift can be seen as the breathing-in of the wind over summer`s sun-heated landscape followed by its exhaling as the land cools with the weakening solar input of fall.

Needless to say, shifting wind patterns on the scale of thousands of miles weigh heavily upon the weather in areas of monsoon climate like those of southern and eastern Asia. In the extreme, there can be striking contrasts in rainfall between as one seasonal wind flow gives way to its compliment.

One area where the Northeast Monsoon brings a big outpouring of rain in the latest summer and fall is the area bordering the western South China Sea, especially the central half of Vietnam. As the Northeast Monsoon takes hold, steamy tropical air off the sea gets driven against the Vietnam highlands, the outcome being the wringing out of torrential rains each and every year. In the wettest of months, normal rainfall can reach two to three feet.

Since Friday, rainfall as of late Monday night, local time, was 10.2 inches, or nearly 26 cms, at Hue, Vietnam. About 9 inches--23 cms--splashed Dong Hoi within this same span of time. At Danang, 4.3 inches (11 cms) poured forth in six hours, alone, Monday night. Yet none of these amounts would be unusual. Another spot hard-hit by seasonal rain was southern Hainan Island, China. Here, one foot of rain (about 30 cms) fell between Friday and Monday evening, local time.