A huge shield of monsoon clouds has covered nearly two-thirds of India, indicating a significant rebound in monsoon activity after a brief monsoon lull. Data captured by the Indian Space Research Organization’s (ISRO) INSAT-3DR weather satellite indicates that nearly 60 to 70% of the country’s land area currently lies under heavy cloud cover.
Satellite images reveal a dense gathering of clouds. The thickest structures are located over the northern plains, which extend across Punjab, Uttar Pradesh, Bihar and West Bengal, while extending densely to the northeast.
Long, active lines fueled by humid winds coming from the Arabian Sea also sweep the southern peninsula. In contrast, western Rajasthan and parts of Tamil Nadu remain relatively clear.
Meanwhile, the India Meteorological Department (IMD) has issued local alerts as monsoon momentum regains.
Regional impact and city-level alerts
Delhi: After a hot and humid weekend with maximum temperatures reaching 40 degrees Celsius, the national capital is entering the most active monsoon phase. The IMD has forecast a sharp intensification of rainfall activity between July 20 and 22, with widespread rainfall, isolated thunderstorms and isolated heavy rainfall across Delhi and adjoining parts of the National Capital Region. Heavy cloud cover and rainfall are expected to bring daytime temperatures down significantly, with maximums falling near 30 degrees Celsius by Tuesday.
Mumbai: A yellow alert was put in place as heavy rain returned over the weekend, with some areas recording more than 30mm of rain in a period of just two hours. The 24-hour weather forecast is that the weather will be generally cloudy with sudden heavy rains in isolated areas, with thunderstorms and winds reaching speeds of 30 to 40 kilometers per hour.
Thane and Palghar: Neighboring areas have also been placed under yellow alert. Residents are advised to expect localized heavy rain, lightning and strong storms consistent with Mumbai’s track as conditions become favorable for sustained rain activity.
Jammu and Srinagar: With cloud temperatures dropping to over minus 80 degrees Celsius, the region faces the highest potential for sudden, violent thunderstorms and localized heavy rains capable of creating sudden hazards in the mountainous terrain.
Patna, Ranchi and Lucknow: Pockets of cloud formations with temperatures dropping below minus 50 degrees Celsius have put the states of Bihar, Jharkhand and Uttar Pradesh on alert for frequent lightning strikes and short-lived spells of heavy rainfall as the main monsoon winds pass overhead.
Bengaluru and Hyderabad: Long bands of moisture moving from the Arabian Sea bring persistent overcast conditions across Karnataka and Telangana. While these systems primarily produce widespread drizzle and steady moderate rain, municipal areas remain alert for sudden thunderstorm cloud accumulation later in the day.
Scientific insights from orbit
Using cloud top brightness temperature (CTBT) data, meteorologists map the severity of these systems. Infrared thermal images recorded temperatures dropping to below minus 80 degrees Celsius over Jammu and Kashmir, indicating exceptionally violent and long thunderstorms heading towards the upper troposphere.
Pockets of minus 50 degrees Celsius were recorded in Bihar, Jharkhand, Uttar Pradesh, the Northeast and along the ranges covering Karnataka, Telangana and Andhra Pradesh.
The IMD noted that the active monsoon trough over northern India acts as a self-powered engine. Experts explained that “every kilogram of water vapor that condenses releases about 2.5 million joules of heat, leading to upward currents that push the clouds to a height of 15 km.”
