After Cyclone Arnab, New Low-pressure Area Forms Over South Andaman Sea

A new weather system has formed over the Bay of Bengal and intensified into a low-pressure area, even as the remnants of very severe cyclone 'Arnab' continue to weaken after moving inland.

The new system is currently over the South Andaman Sea near the Andaman and Nicobar Islands. The India Meteorological Department (IMD) has not yet forecast whether it will intensify into a cyclone or indicated its possible path.

HR Biswas, a senior scientist at the IMD in Kolkata, told the Hindustan Times that a cyclonic circulation over the South Andaman Sea had intensified into a low-pressure area in the early hours of Thursday.

“It is very likely to move in a west-northwest direction and intensify further into a well-marked low pressure over the Andaman Sea and the area adjoining the Andaman and Nicobar Islands during the next 72 hours,” Biswas said.

The IMD has not issued a cyclone warning for the new system. Its further development will depend on how the weather system evolves over the coming days.

When Does A Low-Pressure System Become A Cyclone?

The IMD classifies weather systems according to their wind speeds. A low-pressure area is the initial stage of a system and does not, by itself, indicate that a cyclone will form.

A depression has wind speeds of 31–49 kmph, while a deep depression carries winds of 50–61 kmph. A cyclonic storm has wind speeds of 62–88 kmph, followed by a severe cyclonic storm at 89–117 kmph.

A very severe cyclonic storm has wind speeds of 118–166 kmph, while an extremely severe cyclonic storm has winds of 167–221 kmph. Systems with wind speeds of 222 kmph or more are classified as super cyclones.

October And November Are Cyclone Months

April and May are considered the pre-monsoon cyclone months, while October and November are the post-monsoon cyclone months. During these periods, weather systems such as low-pressure areas and depressions can intensify into cyclones.

The IMD monitors such systems using numerical weather prediction models, multi-model ensembles, satellite observations, Doppler Weather Radars, ocean buoys and coastal observational networks.

According to the department, its forecast accuracy for cyclone track, intensity and landfall point improved in 2023–2025 compared with 2020–2022. For forecasts up to four days ahead, the reported improvements were 15–45% for track, 15–35% for intensity and 10–30% for landfall point.

Cyclone Arnab Weakens After Moving Inland

Meanwhile, the remnants of very severe cyclone Arnab have continued to weaken after moving farther inland.

The system was located over south Chhattisgarh and adjoining south Odisha around 8.30 am on Thursday, according to the official cited in the report. It had moved at a speed of 18 kmph during the preceding six hours.

The official said the system was expected to move farther north and weaken further, eventually becoming a well-marked low-pressure area by Thursday evening.

While Arnab continues to lose strength, the newly formed low-pressure system over the South Andaman Sea remains under observation. The IMD has yet to indicate whether it will develop into a cyclone.