Moderate rain predicted in Capital from July 26 to 29

MONSOON IN DELHI The predictions came on a day when fresh images released by Nasa showed several areas in India detected total rain of over 100cm between June 1 and July 20

nNEWDELHI: There was light rain in parts of Delhi on Friday, and the weekend is likely to see similar conditions with patchy clouds in the sky, weather officials said while separately issuing an intense rain warning for north and northeast India from the beginning of next week, which could compound the problem of flooding in the regions.

The capital is likely to receive moderate rain in this period that is predicted to last from July 26-29.

The predictions came on a day when images released by the United States space agency Nasa showed many areas in India detected total rain of over 100 cm (40 inches) from June 1 to July 20, with Assam — one of the regions hit hardest by flooding — recorded precipitation about 20% higher than normal.

The difference in how monsoon rains are taking place across the country has to do with the location of where the trough of the system is – a line of lower pressure area which triggers precipitation.

“Light rain on Friday was mainly due to a cyclonic circulation over southwest Uttar Pradesh. Palam has recorded about 4.4 mm rain while other stations in south Delhi have also recorded rain. The monsoon trough is presently to the south of Delhi. It is running across south Bikaner, Gwalior, Varanasi, Patna, Bolpur and Haldia in West Bengal. A western disturbance which is over Afghanistan now will affect the north-western region from July 26,” said Kuldeep Shrivastava, head, regional weather forecasting centre.

This will likely lead to a spell of extremely heavy rains over northeast and north India next week, a second official added.

“The western end of the monsoon trough is moving south and the eastern end of the monsoon is likely to move northwards again towards Himalayan foothills. It will be the fourth time it is moving to the hills and may accentuate flooding there,” said RK Jenamani, senior scientist, national weather forecasting centre.

A cyclonic circulation is lying over Jharkhand while another cyclonic circulation is lying over southwest Uttar Pradesh and neighbouring areas. These systems are very likely to merge by July 25 and get less marked.

A western disturbance as a cyclonic circulation is also lying over western parts of Afghanistan and neighbourhood.

Under the influence of these meteorological conditions, widespread and very heavy rains are likely over northeast and east India (Bihar, Sub-himalayan West Bengal and Sikkim) during the next 3 days, IMD said in its Friday bulletin.

Very heavy rains are likely over Uttarakhand, Himachal Pradesh, Uttar Pradesh and Bihar July and over Punjab & Haryana from July 26 to July 28.

The intensity and distribution of rain is likely to increase over Subhimalyan West Bengal, Assam, Meghalaya and Arunachal Pradesh with extremely heavy rain (over 20 cm) likely in many places between July 26 and 29.

IMD in its long range forecast issued on June 1 had forecast that northwest India is expected to receive excess monsoon rain at 107% of the long period average; Central India is likely to get 103% of LPA while south peninsula and northeast India area likely to receive 102% and 96% of LPA respectively with a model error of 8% (+/-).

But until July 24, northwest India has a deficiency of -17% and northeast India has a surplus of 16%, contrary to prediction.

IMD scientists said these trends could overturn in the next couple of monsoon months. But the main reason for this deviation from what was forecast is an unusually calm Bay of Bengal. At least 4 to 6 low pressure systems form over Bay of Bengal normally, bringing rain during monsoon months over the core monsoon region — mainly central India. But this year, there was only one system from June 1.

As on July 23, 36 stations (20 in Bihar, 11 in Assam, 4 in Uttar Pradesh and 1 in West Bengal) are flowing in Severe Flood Situation including Brahmaputra; Gandak and Ghaghra. Severe flood is declared when water level is touching or exceeding the danger level but below highest flood level.