Current Affairs

Issue

A cold wave has been predicted by IMD in Punjab, Haryana, Chandigarh, Gujarat, Rajasthan and Uttar Pradesh over upcoming days.

Details

• A severe cold wave could be seen from December 17 to 21. It is expected that dense morning fog can occur in isolated parts of Haryana and Punjab.

• Ground frost is also on the forecast. The reason could be a western disturbance-caused cyclonic circulation lying over north Pakistan and adjoining Jammu and Kashmir.

• Type of storms that originates in the Mediterranean region and brings winter rainfall to northwest India is termed Western disturbance.

• During its course of time, strong northwesterly and westerly cold winds could be witnessed over north India.

Cold wave

• Cold wave is a weather condition during which the minimum temperature is equal to or less than 10 degree Celsius at a weather station in the plains, and is 4.5 degrees to 6.4 degrees below the normal temperature for that period.  

• A cold wave situation may also occur when minimum temperature is less than or equal to 4 degree Celsius.

• Cold wave for hilly region occurs when minimum temperature is less than or equal to 0 degree Celsius and the minimum temperature is 4.5 degrees to 6.4 degrees below the normal.

Timing of cold wave

Cold waves occur from mid-December to the end of February. It is dependent on weather systems and wind patterns from the middle latitudes.

Entry into India

• The cold air masses brought about by upper-level winds are the main reason for occurrence of cold wave in India.

• Cold waves can also occur due to buildup of an extended area of relatively high pressure over northwest Asia.