A trough/wind discontinuity currently extends from Maharashtra's Vidarbha to south Tamil Nadu, according to the India Meteorological Department (IMD).
Such troughs are essentially elongated zones of relatively low pressure, the presence of which attracts moisture and causes instability in the atmosphere, resulting in the production of rain clouds.
This trough, combined with moist winds, is expected to deliver isolated to scattered light showers across Coastal Andhra Pradesh, Telangana, Rayalaseema, Interior Karnataka, Tamil Nadu, and Kerala over the next five days, from Sunday to Wednesday, April 23-26.
Based on these forecasts, the IMD has issued a yellow warning for the aforementioned states and subdivisions for the next five days. The advice advises citizens to 'be aware' of their local meteorological conditions, particularly during thunderstorms.
Rain is also likely to fall in major South Indian cities such as Bengaluru, Chennai, Hyderabad, Kochi, Thiruvananthapuram, Visakhapatnam, and others during this forecast period. The rain will also have a cooling effect on South India, with regional daytime temperatures forecast to be lower than average. Despite the dip in temperature, IMD predicts highs of 40°C or more in portions of Tamil Nadu and Rayalaseema for Sunday, April 23.
Meanwhile, rainfall in the southern states has been substantially below their individual monthly norms since the beginning of April.
Andhra Pradesh (12.3 mm) received 6% less rainfall than its long-term average for this time period between April 1 and 22. Tamil Nadu (12.2 mm), Karnataka (8.9 mm), and Telangana (6.3 mm) have all seen 'deficits' of approximately 50%, while Kerala (21.6 mm) has experienced a 68% 'big deficit' so far this month.
