Summer resolution

Context:

• Indian Meteorological Department (IMD) has proclaimed that most parts of the country are expected to experience above normal maximum temperatures during the “hot weather season”(March­May), barring parts of peninsular and northwest India, which would see normal or even below normal ‘maximum’ temperatures.

What is the criterion for declaring heat waves in India?

• For Plains and Hilly regions- Heatwaves is considered if the maximum temperature of a station/area reaches at least 40°C or more for Plains and at least 30°C or more for Hilly regions.
• Based on Departure from Normal Heat Wave: Departure from normal is 4.50°C to 6.40°C Severe Heat Wave: Departure from normal is >6.40degree C
• Based on Actual Maximum Temperature Heat Wave: When actual maximum temperature ≥ 450°C Severe Heat Wave: When actual maximum temperature ≥47

What are favorable conditions for Heat wave?

• Transportation / Prevalence of hot dry air over a region -There should be a region of warm dry air and appropriate flow pattern for transporting hot air over the region.
• Absence of moisture in the upper atmosphere- As the presence of moisture restricts the temperature rise.
• The sky should be practically cloudless -To allow maximum insulation over the region.