Poor rain distribution: 5 districts in Delhi report deficient rainfall

Five districts in Delhi have reported deficient rainfall this monsoon so far due to poor distribution of rains, according to India Meteorological Department data. On average, Delhi has recorded a rainfall deficiency of 23 percent — gauging 90.4 mm of rains as against a normal of 116.9 mm since June 1, when the monsoon season starts.

Till a week ago, on July 5, the city as a whole had logged 10 percent excess rainfall. But rains have repeatedly given the capital a miss since then. The short spells of rain on Monday and Tuesday morning — a result of convective activity — remained restricted to a few areas. West Delhi has recorded a rainfall deficit of 60 per cent (54mm of rain as against the normal of 135.8mm) since the start of the monsoon season.

Southwest Delhi has logged a shortfall of 51 per cent — gauging just 59.8 mm of rainfall against a normal of 122.7mm in this period.

The IMD data showed Northeast Delhi has gauged 43 per cent less rainfall than a normal of 135.6 mm. The rainfall deficit in Central and South Delhi stood at 29 percent and 22 percent, respectively. Central Delhi received 96.3mm rains and South Delhi 106.1mm since June 1.

East Delhi with 218.1 mm has received 61 percent more rainfall than normal. The IMD has had a hard time providing accurate predictions about rainfall in the capital. Despite favorable conditions, the Safdarjung Observatory, Delhi’s primary weather station, has recorded just 4.4 mm of rainfall in the last 11 days.

It has gauged 146.1 mm of rainfall against a normal of 143.9 mm since June 1. Of this, 117.2 mm came in just 24 hours ending at 8:30 am on July 1.

When it finally rained in parts of Delhi on Monday after a string of wayward forecasts, weather forecasters said the rain came from convective clouds and it is difficult to provide an accurate prediction about their formation.

”We knew about the possibility of the formation of convective clouds. There were high humidity and high temperatures but it is hard to give a micro-forecast in terms of exact location and intensity. So one cannot be certain about rainfall over a particular place,” said Mahesh Palawan, vice-president (meteorology and climate change), Skymet Weather.

Convective clouds develop vertically by convection — warm air rising and cooling down to form clouds. These clouds dissipate after giving short and intense spells of rain, the meteorologist said.

Non-convective precipitation events are less intense but last longer and give a steadier rainfall.

Though monsoon is associated with non-convective precipitation, ”we have been witnessing convective development in the monsoon period for the last 10 years or so due to climate change”, Palawat said.

Convective activity is generally reported during the pre-monsoon period.