Correct Answer - Option 4 : 1, 2 and 3
The correct answer is 1, 2 and 3.
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Western Disturbances
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The western cyclonic disturbances are weather phenomena of the winter months brought in by the westerly flow from the Mediterranean region. Hence, statement 1 is correct.
- Western Disturbances develop in the mid-latitude region (north of the Tropic of Cancer), not in the tropical region, therefore they are called as mid-latitude storms or extra-tropical storms. Hence, statement 2 is correct.
- Extra-Tropical Cyclones are also called as winter storms and blizzards.
- A high-pressure area over Ukraine and neighbourhood consolidates, causing the intrusion of cold air from Polar Regions towards an area of relatively warmer air with high moisture.
- This generates favourable conditions for cyclogenesis in the upper atmosphere, which promotes the formation of an eastward-moving extratropical depression.
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They gradually travel across the middle-east from Iran, Afghanistan and Pakistan to enter the Indian sub-continent.
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Impact of Western disturbance
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Western disturbances plays important role in bringing moderate to heavy rain in low-lying areas and heavy snow to mountainous areas of the Indian Subcontinent.
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This disturbance is usually associated with a cloudy sky, higher night temperatures and unusual rain. Hence, statement 3 is correct.
- Precipitation during the winter season has great importance in agriculture particularly for rabi crops including wheat, which is one of the most important Indian crops.
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During the monsoon season, western disturbances may occasionally cause dense clouding and heavy precipitation.
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Strong western disturbances can help residents, farmers and governments avoid many of the problems associated with water scarcity.
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Weak western disturbances are associated with crop failure and water problems across north India.