Low pressure area likely to form over Bay of Bengal in September
A low pressure area (LPA) is likely to form over north Andaman sea and adjoining East central Bay of Bengal by around September which is expected to intensify further
A low pressure area (LPA) is likely to form over north Andaman sea and adjoining East central Bay of Bengal by around September which is expected to intensify further.
Once an LPA is formed, it is likely to move west-northwestwards with possibility of gradual intensification, India Meteorological Department (IMD) has warned on Saturday. The post monsoon tropical cyclone season also begins in October but meteorologists said it’s too early to say with certainty how far the system would intensify and what would be its track.
“There are two directions it can take. One is to move towards Myanmar in which case its intensification may not be strong, another is to move across Bay of Bengal. The sea surface temperatures are high over BoB with 31 degree Celsius over some pockets and if the system travels over warm waters for several days, it will most certainly intensify. The system in any case will intensify to a depression. The forecast will be clearer in 2-3 days,” said a senior IMD official.
Data with Indian National Center for Ocean Information Services indicates most parts of Bay of Bengal are recording SSTs of 30-to-32-degree C.
He further explained that the genesis and intensification of the system will depend on the retreat of monsoon. “If the monsoon surge is still active then it will definitely interact with the system,” he added. Normally cyclones do not develop during monsoon season. The average annual frequency of tropical cyclones in the north Indian Ocean (Bay of Bengal and Arabian Sea) is about 5. The months of May-June and October-November are known to produce cyclones of severe intensity.
Following scanty rains in August, monsoon has revived in September. “Several low-pressure systems and cyclonic circulations formed in September as against August when we normally see them form frequently. A favourable Madden Julian Oscillation was a big factor in revival of monsoon and development of these systems,” he said. MJO is described as an eastward moving pulse of cloud and rainfall near the equator that typically recurs every 30 to 60 days.
Heavy to very heavy rainfall is likely to continue over Bihar, Jharkhand, Sub Himalayan West Bengal & Sikkim and over Northeast India during next 2 days and decrease thereafter, IMD said on Saturday. Conditions are becoming favourable for withdrawal of Southwest Monsoon from parts of West Rajasthan from around September 25. The normal date for monsoon withdrawal to begin is September 17 and completely withdraw by October 15. The monsoon season officially ends on September 30.
“Due to anti-cyclonic flow developing over northwest India at lower tropospheric levels and dry weather prevailing over parts of southwest Rajasthan, conditions are becoming favourable for withdrawal of Southwest Monsoon from parts of West Rajasthan from around September 25,” IMD said. A cyclonic circulation lies over Southwest Bihar & neighbourhood extending upto 4.5 km above mean sea level which is causing monsoon to be active over east India.
There is a 6% deficiency in monsoon rainfall; 19% deficiency over east and northeast India; 10% deficiency over South Peninsula; 1% deficiency over central India and 2% excess over northwest India.
HT reported on Friday that there is about a 95% chance that 2023 will be the warmest or the second-warmest year on record according to a briefing by National Oceanic and Atmospheric Administration (NOAA). NOAA warned that several more months — possibly stretching into 2024 — could continue the heat trend thanks to the El Nino weather pattern remaining strong.
M Mohapatra, director general, IMD had said a forecast will soon be issued for the post monsoon period of October-November-December but normally temperatures are expected to be above normal during a strong El Nino period. “Usually, winters are not expected to be very cold but apart from El Nino there are many other local factors that matter.”
El Nino is characterized by an unusual warming of waters in the eastern equatorial Pacific, which has a high correlation with warmer summers and weaker monsoon rains in India.