With a La Nina or a cooling of the central Pacific Ocean expected to firmly take root in September, the India Meteorological Department (IMD) has forecast a rainy September with several parts of north India forecast to receive heavy rainfall. 

La Nina

• After an El Niño event weather conditions usually return back to normal.
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• However, in some years the trade winds can become extremely strong and an abnormal accumulation of cold water can occur in the central and eastern Pacific. This event is called a La Niña.
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• A strong La Niña occurred in 1988 and scientists believe that it may have been responsible for the summer drought over central North America. During this period, the Atlantic Ocean has seen very active hurricane seasons in 1998 and 1999.
• One of the hurricanes that developed, named Mitch, was the strongest October hurricane ever to develop in about 100 years of record keeping.

Effects of La Nina

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2. Some of the other weather effects of La Niña include
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4. Abnormally heavy monsoons in India and Southeast Asia,
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6. Cool and wet winter weather in southeastern Africa, wet weather in eastern Australia,
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8. Cold winter in western Canada and northwestern United States,
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10. Winter drought in the southern United States.