This may be the driest September since 2004, shows IMD data
In September 2004, 3mm rain was recorded in Delhi. In September 2015, the city recorded 22mm rain. The average normal monthly rainfall for September is 129.8mm.Updated: Sep 25, 2020, 01:02 IST
Delhi has recorded less than 21mm rainfall this month so far, the least amount of rain in September since 2004, according to India Meteorological Department (IMD) data.
In September 2004, 3mm rain was recorded in Delhi. In September 2015, the city recorded 22mm rain. The average normal monthly rainfall for September is 129.8mm.
This year, the Safdarjung observatory, which is considered representative of Delhi’s weather, recorded only three days of rain on September 5, 6 and 8.
According to IMD, monsoon is likely to begin withdrawing from Monday — a week later than the normal date. The monsoon season will officially end on September 30.
“While the average monthly rainfall considered normal for September is around 129.8 mm, the three days of rain this September accounted for 20.9 mm, which shows a huge deficit. This time, the two major factors responsible for triggering rain --- western disturbance and low-pressure system close to Delhi --- were missing. The monsoon trough remained largely in the Himalayan foothills and did not reach closer to Delhi. Even on the three days when some rainfall was recorded, the system was weak and not enough to cover up the deficit for this month,” said Kuldeep Srivastava, IMD’s head of the Regional Weather Forecasting Centre (RWFC).
He said it may cloudy over the next two days but there is no weather system that can induce rain in Delhi. “We are closely monitoring the withdrawal of monsoon. In the north-west region, it starts withdrawing from west Rajasthan and then from Delhi. It is expected to withdraw over the next few days,” said Srivastava.
The normal date for the beginning of the monsoon’s withdrawal from north-west India is September 17, and October 15 for the complete withdrawal from the country, according to the new monsoon onset and withdrawal dates issued by IMD in April this year.
Until last year, the normal date for commencement of withdrawal was September 1 and October 15 for complete withdrawal. The new onset dates are based on monsoon data from 1961 to 2019 and withdrawal dates are based on data from 1971 to 2019 analysed by scientists in IMD, Pune.
“We are expecting rainfall to stop and moisture to reduce beginning next week because the low-pressure area that is lying over east Uttar Pradesh is likely to move eastwards. We are not seeing the possibility of development of any other system that could bring rain next week to the north-western region,” said K Sathi Devi, head, National Weather Forecasting Centre.
R K Jenamani, senior scientist at IMD’s National Weather Forecasting Centre (NWFC) said while overall Delhi has had a normal monsoon this year, September has remained rain-deficient in not just Delhi but many other parts of northwest India, including Jammu and Kashmir.
“This month, the low-pressure system did not move beyond Madhya Pradesh, which otherwise goes to Punjab and Rajasthan and then moves towards Delhi. Also, there was no disturbance to pull the low-pressure system forward. When these two factors interact, it brings rain, which was absent this September,” said Jenamani.
This year so far, Delhi (from June 1- September 24) has received 467.7 mm rain -- a 19% deficit, according to weather department officials.