(Last Updated on : 23/01/2009)
The months of October and November are known for retreating monsoons. During this season, the monsoon trough of low pressure turns weaker and is progressively replaced by high pressure. This results in the withdrawal of monsoon. The out-reach of the monsoons begin to turn weak. Their influence over the Indian land-mass begins to wither. By the outset of October they recede from the Northern Plains.
The months of October-November form a period of conversion- from a hot rainy season to dry winter conditions. The withdrawal of the monsoons is punctuated by clear skies and rise in temperature. The land is however still damp. Due to the circumstances of high temperature and moisture, the weather becomes somewhat humid. This is generally referred to as `October heat`. In the second half of October the mercury begins to descend speedily, especially in northern India.
The low pressure conditions which once dominated over north-western India gets channelised to the middle of Bay of Bengal by early November. This reposition of the low pressure area is far from being easy-going. The period is connected with happening of cyclonic depressions, which takes shape over the Andaman Sea. Those that manage to traverse the eastern coasts of southern peninsula, cause profound and extensive downpours. These tropical cyclones are often pretty devastating. The densely populated deltas of the Godavari, Krishna and Kaveri are their chosen target area. Not a single year is ever tragedy-free. At times, these tropical cyclones hit Sundarbans and Bangladesh too. Majority of the rainfall of the Coromandel Coast is gained from depressions and cyclones.
Distribution of Precipitation in India
Yearly rainfall of over 300 cm is distributed over parts of western coast and northeastern India. A yearly rainfall of less than 50 cm is received in western Rajasthan and bordering regions of Gujarat, Haryana and Punjab. Rainfall is likewise extremely low in the interiors of Deccan plateau, east of the Sahyadris. A third area of low rainfall is around Leh in Kashmir. The remaining country gets reasonable rainfall. Snowfall is confined to the Himalayan region.
Owing to the inexplicable modifications of monsoon, the yearly rainfall is extremely uneven from year to year. Inconsistency is high in the areas of scanty precipitation. Areas of high rainfall are likely to be distressed by floods. Regions of sensible and low rainfall are prone to droughts.