Sitrang effect: Heavy rainfall in Northeast India

Parts of Assam and northeastern states are expected to receive heavy rainfall after Cyclone Sitrang made landfall over Bangladesh late on October 24, 2022. 

Sitrang has weakened into a depression over northeast Bangladesh. It is very likely to continue to move north-northeastwards and weaken into a low pressure area, according to a press note by India Meteorological Department. 

Read more: Cyclone Sitrang: Bengal gears up to combat Sundarbans impact

Moderate rain is very likely to occur at most places over Arunachal Pradesh, Assam,Meghalaya Nagaland, Manipur, Mizoram and Tripura, it added.  

IMD had earlier predicted widespread light or moderate rainfall over the region between October 24 and 26. Earlier forecasts showed isolated heavy falls and thunderstorms or lightning between 25 and 26 October 2022.

Warnings on October 25, 2022, showed heavy rain over parts of Assam. 

Parts of Tripura are also expected to receive heavy to very heavy rainfall with squally winds today, according to IMD forecast on October 25. 

“After making landfall, it will move in the northeasterly direction, impacting Manipur, Mizoram, Tripura, Nagaland, eastern parts of Assam and Arunachal Pradesh,” Mahesh Palawat, vice president, Meteorology and Climate Change at Skymet Weather Services Private Limited, had earlier told Down To Earth.

Within Assam, Sonitpur, Dhemaji, Tinsukia among other areas are expected to see heavy rainfall October 25. 

Sunit Das, Scientist-D at the Regional Meteorological Centre of the IMD, told DTE that he does not expect a flood due to the cyclone unless the system intensifies. “But localised flooding may be expected. We may also see water logging in urban areas,” he said.

Palawat also agreed. “After making landfall, the intensity will reduce. We do not expect extremely heavy rains in the northeast,” he noted.

These regions may see moderate showers and isolated heavy spells. “But it will not be widespread,” he added.

Experts, however, warned that forecasts may change. “With the weather system, there can be changes every six hours,” D Sivananda Pai, director at the Kottayam-based Institute for Climate Change Studies, told DTE.

Forecasting weather ten days ahead comes with some level of uncertainty, he explained. We are more confident with forecasts done 24 hours earlier, he said, adding that we need to keep a watch over the northeast region.

Earlier this month, Assam and Arunachal Pradesh witnessed heavy rainfall and floods, according to reports. 

The affected districts are Darrang, Dhemaji, Dhubri, Dibrugarh, Golaghat, Jorhat, Lakhimpur, Kokrajhar, Majuli, Nagaon, and Tinsukia, news reports state.

On October 21, IMD confirmed that a low-pressure area had formed over the north Andaman Sea and the adjoining regions of the south Andaman Sea and Southeast Bay of Bengal.

Read more: Depression in Bay of Bengal intensifies: Cyclone Sitrang on track

According to NOAA, low-pressure areas draw air into them, creating winds and undesirable weather.

But it is not exceptionally warm to support the rapid intensification of cyclones, Roxy Mathew Koll, a climate scientist at the Indian Institute of Tropical Meteorology, earlier told DTE.

Cyclone Sitrang started landfall around 9:00 pm (October 24, 2022) along the Bangladesh coast between Barishal and Chattogram, close to Bhola, according to the latest cyclone update from the Bangladesh Meteorological Department (BMD). 

The weather agency predicted the landfall process to take up three-four hours. It said wind speeds around 62 kilometres per hour (kmph), gusting up to 88 kmph were prevailing in the region — within 54 km of the cyclone centre. 

European Center for Medium-Range Weather Forecasting data as visualised by the Windy website showed that the landfall process had ended as of 11:00 pm, October 24.