Western Disturbances

Western Disturbances are like weather travelers on a journey from the west. These low-pressure areas hitch a ride on the winds that blow from the west to the east. Picture them starting their adventure in the Mediterranean region, moving westward, and eventually arriving in India. They bring along a lot of moisture, collected from the Mediterranean sea and the Atlantic Ocean. When they hit the Himalayas in India, it’s like a roadblock, and that’s when things get interesting – rain and snow show up in northern India as a result. So, these weather wanderers are essentially the bearers of rain and snow for this part of the world.

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What are Western Disturbances?

Western disturbances are storms that roll in from places like the Caspian or Mediterranean Sea, and they’re the reason we get unexpected rain in northwest India, according to the India Meteorological Department (IMD).
They’re basically big storms that start outside the tropics and bring in low pressure, resulting in sudden showers, snow, and fog in the northwest region.
The name “Western Disturbance” makes sense because these storms move from the west to the east.
Picture this: these disturbances ride on fast winds called high-altitude westerly jet streams, like huge wind highways crossing the Earth from the west to the east.
The term “disturbance” in Western Disturbance means an area where the air pressure is a bit off-kilter, not as stable as it should be.
Nature likes balance, so when the air in an area feels pressured, it tries to even things out.
When we say “extra-tropical storm,” we mean it’s a storm with low pressure, and the “extra-tropical” part means it’s happening outside the tropics.
These Western Disturbances bring rain, snow, and fog to northern India, starting with showers in Pakistan.
The moisture these disturbances carry comes from the Mediterranean Sea or the Atlantic Ocean.
They’re like the weather heroes for the Rabi crop in the Northern subcontinent, bringing in the right conditions for winter and pre-monsoon rain.
But, watch out! Western Disturbances aren’t always bringing good vibes. Sometimes, they can be troublemakers, causing floods, landslides, dust storms, hailstorms, and even cold waves that can mess things up for people and their stuff.

Formation of Western Disturbances

Western Disturbances start off as extra-tropical cyclones originating in the Mediterranean Sea.
The process begins with a high-pressure area forming over places like Ukraine and nearby countries, leading to the movement of cold air from the Polar Regions.
This cold air collides with a region of warmer air containing high moisture content.
The shift in pressure, from cold to warm air, creates ideal conditions for the development of cyclones in the upper atmosphere.
This, in turn, facilitates the formation of an eastward-moving extratropical depression over the sea.
Subsequently, these disturbances travel across the Middle East, passing through Iran, Afghanistan, and Pakistan.
Finally, they enter the Indian subcontinent, influencing weather patterns in the region.

Variation in Western Disturbances

Last year, Delhi experienced its rainiest October in 65 years. The Safdarjung weather observatory reported 122.5 mm of rainfall, way above the usual 28 mm, all thanks to western disturbances.
January and February of the same year also saw more rainfall than usual. On the flip side, November 2021 and March 2022 had zero rainfall. Surprisingly, the summer heat kicked in unusually early, with heat waves hitting by the end of March 2022.
February 2022 stood out for its cool temperatures, thanks to multiple western disturbances bringing in clouds. In fact, it recorded the lowest maximum temperature in 19 years.
March 2022 missed out on active western disturbances in northwest India. With no clouds or rain, temperatures stayed high.

Impact of Western Disturbances

Rain and Snowfall: Western disturbances play a big role in bringing good rain to low areas and a lot of snow to the mountains in the Indian Subcontinent.
Cloudy Skies and Unusual Rain: When these disturbances happen, you can expect cloudy skies, warmer nights, and sometimes unexpected rain.
Agricultural Impact: The rain and snow are crucial for Rabi crops. Farmers rely on these weather patterns for a good harvest.
Potential Hazards: However, too much rain can be a problem. It can damage crops, cause landslides, floods, and avalanches, posing a threat to both agriculture and people.
Cold Waves and Fog: In the Indo-Gangetic plains, these disturbances can bring cold waves and dense fog, affecting daily life and visibility.
Stability and Change: These weather conditions stick around until another western disturbance comes along to shake things up.
Monsoon Connection: Interestingly, when these disturbances travel across northwest India before the monsoon season, they can influence the onset of monsoon, creating temporary changes in the region’s weather patterns.