The monsoon embraced Delhi in an impressive manner on June 30 but rains have repeatedly given the capital a miss since then. The India Meteorological Department (IMD) had made a series of inaccurate forecasts for the arrival of monsoon in the national capital.
On Sunday, the IMD forecast said that Delhi is likely to get only light or very light rain over the coming week. While an earlier forecast for Sunday indicated moderate rain, it was later modified to light rain.
Delhi is still witnessing a dry monsoon season with the maximum temperature settled at 34.9 degrees Celsius, and the temperature of wet bulb climbing up to 30 degree celsius, causing discomfort.
In the last 10 days, Delhi's base weather observatory, the Safdarjung Observatory, has recorded just 2.6 mm rainfall. The monsoon in Delhi began on a bumper note with the national capital receiving very heavy rainfall between June 30 and July 1. It has been a dry spell since then.
But IMD has been issuing rainfall warnings for almost every day. On July 1, the weather office issued the orange alert. It issued the yellow alert for the next six days. The city received only 2 mm rainfall in the next three days.
On July 4, the IMD issued a yellow alert for July 5 and an orange alert for July 6, which was later shifted to July 7.
The IMD later predicted "fairly widespread to widespread rainfall activity" over west Uttar Pradesh, Punjab, Haryana, Chandigarh, Delhi and Rajasthan on July 9 and July 10, and issued a yellow alert, warning of moderate rainfall in the capital on Sunday. But that did not happen either.
"The low pressure area had pulled the trough towards central India, leading to heavy rainfall there," said Mahesh Palawat, vice president (meteorology and climate change), Skymet Weather.
"It was expected that the western end of the monsoon trough would again shift towards the north after the low pressure area degenerated.
However, the development of a cyclonic circulation over southwest Rajasthan and adjoining parts of south Pakistan in the last 24 hours did not let the monsoon trough come near Delhi and neighbouring areas.
It is still stuck south of Delhi and passes through Bikaner and Kota," he said. Delhi won't get any rain on Monday and Tuesday. Rain is likely on July 13 and July 14 after the low pressure area crosses Gujarat and the monsoon trough shifts towards the north, the meteorologist said.
According to experts, there are four factors responsible for rain in Delhi: the monsoon trough line passes through the city to north-west UP, Haryana and east Rajasthan; low pressure area development; western disturbance with moisture; and local convective clouds due to local heat and moisture. But, even change in wind or difference in pressure created by local heat can affect any of four factors in a very short time.One of the major reasons being attributed to the continuous faulty forecast this year is the difficulty in predicting the interaction of easterly and westerly winds. Parts of Uttar Pradesh and Haryana have been receiving moderate to heavy rainfall over the past few days, but Delhi has remained largely dry. July and August are the rainiest months in Delhi.
While July sees around 187 mm of rain, it is usually 232.5 mm in August. Monsoon reached Delhi on June 30 – three days late – and the city received heavy rainfall for a couple of days after.
Since then, however, it has received only light rainfall or traces. According to the IMD, Delhi has received 89.2 mm of rain (city average) since June 1 this year, which is when the monsoon arrives in Kerala. This is a deficit of 15% which, as per the IMD, is a normal deviation.