- 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.