Where does the low-pressure area develop during November?

In geography and climatology, students often study how seasonal winds and pressure systems affect rainfall and weather in India. November is the transition month from the southwest monsoon (summer monsoon) to the retreating monsoon (northeast monsoon).

Step 1: Development of Low-Pressure Area

• During November, the low-pressure area develops over the Bay of Bengal.
• This happens because:
  • The landmass of northern India and the subcontinent cools down quickly after monsoon withdrawal.
  • The Bay of Bengal, however, retains heat longer.
  • This temperature contrast creates a low-pressure zone over the Bay of Bengal.

Step 2: Weather Consequences

1. Formation of Cyclonic Disturbances
   • The Bay of Bengal low-pressure system often intensifies into depressions and cyclones.
   • These cyclones move towards the eastern coast of India (Andhra Pradesh, Tamil Nadu, Odisha) and sometimes towards Bangladesh and Myanmar.
2. Retreating Monsoon Rainfall
   • The northeast monsoon winds pick up moisture from this low-pressure zone over the Bay of Bengal.
   • As a result, states like Tamil Nadu, Andhra Pradesh, Kerala, and Karnataka receive their major share of rainfall during this period.
   • For example, Chennai gets nearly half of its annual rainfall in October–November due to these systems.
3. Impact on Life and Economy
   • While this rainfall supports winter cropping (Rabi crops) in South India,
   • The cyclones also cause flooding, damage to infrastructure, and loss of life and property.

During November, a low-pressure area develops over the Bay of Bengal. This system often leads to the formation of cyclones and causes heavy rainfall along the eastern coast of India, especially in Tamil Nadu and Andhra Pradesh, marking the retreating monsoon or northeast monsoon season.