Source : INDIA TODAY NEWS
An extraordinary atmospheric shift has turned the intense peak summer heat of North India on its head. On Saturday, May 30, a massive weather system swept across the northern plains, bringing violent dust storms, widespread rain, and a historic drop in temperatures.
Residents woke up to a reality that felt closer to December than May.
According to the India Meteorological Department (IMD), maximum temperatures crashed by 10 to 15 degrees Celsius below normal levels across Punjab.
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Chandigarh recorded a maximum temperature of just 25.3 degrees Celsius, a figure that mirrors peak winter standards.
Other Northern, Central, and Eastern states saw a significant cooling effect, with daytime temperatures plunging 4 to 8 degrees Celsius below the seasonal average.
This dramatic transformation is the work of a powerful Western Disturbance.
These are extratropical storms, or large-scale low-pressure systems that form outside the warm tropics, usually over the Mediterranean Sea.
Driven by the subtropical westerly jet stream, a high-altitude ribbon of fast-moving air, these systems travel thousands of kilometres eastward across Asia to reach India.
THE SCIENCE OF THE SUMMER FREEZE
While these disturbances typically dominate winter weather by bringing snow to the Himalayas, their late-season appearances trigger explosive atmospheric reactions.
When cold air migrating from the mid-latitudes collides with the intense surface heat of the Indian summer, it creates a highly unstable environment.
The mechanism behind the violent dust storms lies in the creation of powerful downbursts.
As heavy rain falls through dry air beneath the clouds, the water evaporates rapidly, cooling the surrounding air. This cold air becomes incredibly dense and heavy, causing it to sink rapidly and slam into the ground, expanding outward as ferocious winds.
In arid regions like Rajasthan and Punjab, these gust fronts lift massive walls of loose dust and sand into the sky.
Concurrently, the interaction between the upper-level storm and moist easterly winds blowing from the Bay of Bengal creates low-level moisture convergence.
This process forces the warm, humid air upward, feeding the growth of massive cumulonimbus or thunderstorm clouds.
PERSISTENT COOLING INTO JUNE
The aftermath of this atmospheric battle is a widespread cold pool. The combination of thick cloud cover blocking solar radiation, cold air advection, which is the horizontal movement of cooler air masses replacing warmer ones, and evaporative cooling from the rainfall has locked in the drop in temperature.
This cool spell is not a transient, 24-hour event.
Meteorologists indicate that easterly winds will continue to dominate the regional weather pattern over the next three to four days.
With limited thunderstorm activity persisting, North India is set to enter June with unusually suppressed temperatures, offering an extended reprieve from the typical summer heatwaves.
– Ends
SOURCE :- TIMES OF INDIA
