Context:
Indian Meteorological Department(IMD) has predicted a fresh western disturbance is likely to cause isolated to scattered rainfall and snowfall over the Western Himalayan Region on the 17th and 18th February 2024.
About:
∙ It also predicts a gradual rise in minimum temperatures by 2 to 4 degrees Celsius over Northwest India during the next 5 days.
Western disturbances
∙ Western disturbances are the weather systems which are seen as extra tropical upper air trough (extended low pressure area) or/and cyclonic circulations (CCs) in mid- latitude westerlies that move from west to east across Himalayan region.
∙ They originate in the Mediterranean region or Caspian Sea.
∙ It brings crucial winter rainfall to northwest India, encompassing areas like Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Punjab, and parts of Rajasthan.
Formation:
∙ Embedded in the mid-latitude westerly jet stream, a fast-moving ribbon of air high in the atmosphere.
∙ Gain moisture as they travel over the Mediterranean Sea, Black Sea, or Caspian Sea.
∙ Move eastward towards the Indian subcontinent, bringing clouds, rain, and sometimes snow.
Impacts:
∙ Precipitation: Responsible for a significant portion of winter rainfall in the northwest region, crucial for agriculture, water availability, and replenishing snow reserves in the Himalayas.
∙ Temperature: Can cause temporary dips in temperature, providing respite from harsh winters.
∙ Other Impacts: Can sometimes bring strong winds, thunderstorms, and fog, requiring weather preparedness measures.
Significance:
∙ Lifeblood for agriculture: Winter rainfall from Western disturbances is vital for crops like wheat, barley, and oilseeds, impacting millions of farmers.
∙ Hydropower generation: Contribute to hydroelectricity generation, a clean and renewable energy source.∙ Maintain ecological balance: Support healthy ecosystems in the Himalayas and contribute to water availability in downstream regions.
