People are excited for the monsoon to come this year to relieve themselves from the scorching heat. Generally, Delhi’s date with monsoon happens in the last week of June, but this time it is making the wait for another one week.
The Indian Meteorological Department on Tuesday said that the onset of monsoon could occur after seven days as the weak monsoon phase is beginning over central, Peninsular and northwest India during the next seven days courtesy unsuitable meteorological conditions.
The country has received 37% more rain than it generally does in June till Monday. It witnessed 76% in northwest India, 58% in central India, 24% over the southern peninsula and 13% in east and northeast India.
“Southwest monsoon 2021 has so far covered most parts of the country except parts of Rajasthan, Delhi, Haryana and Punjab. However, further progress of monsoon over the remaining parts of the country is unlikely during the next seven days,” said the Indian Meteorological Department in its statement.
On Tuesday, the air quality in the national capital deteriorated as the overall Air Quality Index (AQI) reached 127 in the ‘moderate’ category. However, the System of Air Quality and Weather Forecasting And Research said that AQI could deteriorate and remain in the ‘satisfactory’ to ‘moderate’ category for the upcoming three days.
The Indian Meteorological Department cited the reason behind the delay: An elongated area of low pressure in the westerlies named trough; It has been there for the past ten days.
Westerlies are usually fragile in June as easterly monsoon winds come into effect. Still, the trough in westerlies has been oscillating over northwest India this year, weakening the monsoon period. On Monday, the mid-latitude westerlies have reinforced again as a western disturbance (a cyclone placed in the Mediterranean region) arrived at the Western Himalayan region.
“There are chances of cloud formation on June 25 while parts of Delhi may witness very light rain on June 26. The weather is largely expected to remain dry over the next seven days and hence, the onset of monsoon may be late,” said IMD scientist Kuldeep Srivastava.
He added, “The capital recorded a hot day on Tuesday as the maximum temperature rose to 39.8 degrees Celsius, one degree above normal. The minimum temperature was recorded at 27.4 degrees Celsius, one degree below normal. The relative humidity oscillated between 81% and 31%.”
The monsoon has reached most parts of the country except some parts of Delhi, Rajasthan, Haryana and Punjab. As per the IMD, the advancement of monsoon is unlikely in the next seven days. The northern limit monsoon continues to go through Bhilwara, Barmer, Dholpur, Aligarh, Meerut, Amritsar and Ambala.
The Madden-Julian Oscillation (MJO) is an oceanic-atmospheric process that leads to intra-seasonal variability in weather behaviour. Its location and amplitude effectively state the pace of tropical convection and features like reduced pressure systems over the north Indian Ocean.
It is staying in Phase 1 (East Africa) with an amplitude of more than one, which is not appropriate for improving the convection over the north Indian Ocean region and monsoon rainfall activities, the IMD said.
IMD’s Senior Scientist RK Jenamani said, “Sometimes such variations happen when instead of monsoon winds, westerlies start dominating. The timing is very important because such large-scale feature variations can slow down the progress of monsoon. Rains in east and northeast India will continue because contribution of moisture and convection from Bay of Bengal is still active. We will update as soon as the monsoon starts strengthening again.”
