EXCLUSIVE| Cyclone Arnab: 3 Days of Heavy Rain Forecast for Odisha; Bhubaneswar, Cuttack face severe Waterlogging Risk

Bhubaneswar: With the national forecaster, IMD, declaring that a cyclone is brewing over the warm waters of the Bay, it seems Cyclone Arnab – aptly meaning 'the Ocean' – is poised to unleash torrential rains over Odisha, triggering risks of severe flash flood threats across the State.

Even as multiple global forecasting engines have converged on a precise track pointing toward the Coastal Andhra Pradesh shoreline, the sheer scale and internal machinery of the brewing tropical system ensure that Odisha will bear a massive, extended brunt of the storm's fury.

The India Meteorological Department (IMD) has officially declared that a potent cyclonic system is organizing over central bay waters. Christened Cyclone Arnab – a name meaning "The Ocean," contributed by neighboring Bangladesh – the system is living up to its moniker, rapidly consolidating over deep tropical waters.

However, the most unique aspect of this developing storm is its uneven impact distribution. While Andhra Pradesh prepares for the initial, violent punch of landfall, atmospheric steering currents and structural constraints mean that Odisha is slated to record three continuous days of widespread, heavy rainfall from October 27 to October 29.

For the state of Odisha, and specifically the high-density twin cities of Bhubaneswar and Cuttack, the upcoming week demands peak vigilance as a complex web of atmospheric forces scripts a narrative of intense precipitation, shifting warnings, and localized urban flooding hazards.

The Atmospheric Machinery: The 5.8 km High Engine and the "Umbilical Cord"

To understand why a system heading toward Andhra Pradesh will unleash a three-day deluge hundreds of kilometers to the north in Odisha, one must look at the atmospheric dynamics currently at play.

On the day a Low Pressure Area (LPA) is born, it requires a continuous feed of energy to transition into a organized tropical vortex. For Cyclone Arnab, this structural nourishment is being delivered by a low-level atmospheric trough running from the Arabian Sea across Kerala to coastal Tamil Nadu. Extending up to 1.5 kilometers into the troposphere, this trough acts like an atmospheric umbilical cord, channeling a relentless supply of tropical moisture and heat directly into the system's core.

This moisture feeds a massive, vertically stacked cyclonic circulation that currently extends up to 5.8 kilometers above mean sea level. A vertical column of this magnitude acts as a giant thermodynamic engine. As it draws up the high-octane moisture from the warm bay waters, the latent heat released through condensation drives rapid drop in central atmospheric pressure, accelerating the system through the stages of intensification.

Because the vertical structure is so tall and wide, its outer rainbands stretch across vast distances, meaning the northern moisture tail of the storm will remain tightly pinned over Odisha even while the core eyes a southern landfall.

The Three-Day Deluge in Odisha: Chronology and District Impact

While Coastal Andhra Pradesh bears the initial brunt of a Red Warning on October 27, the IMD rainfall models display a prolonged, widespread (WS) rainfall signature for Odisha spanning three full days. This extended duration occurs because as the core makes landfall, the system's forward speed slows over land, causing its massive moisture-dense northern shield to stall directly over Odisha.

Day 1: Tuesday, October 27 (The Pre-Landfall Approach)

As Cyclone Arnab makes its final approach toward Kakinada, its outer bands will sweep across the Odisha border. Widespread rain will commence across the coastal strip.

·         Districts Implicated: Ganjam, Gajapati, Puri, Jagatsinghpur, and Kendrapara.

·         Intensity: Heavy to very heavy rainfall (7 to 20 cm) in isolated patches. The IMD has placed southern and coastal Odisha under an Orange Warning for this day, as gusty squally winds begin to pick up along the marine boundary.

Day 2: Wednesday, October 28 (The Landfall Equalization)

This is the peak of the meteorological event. As the eye of the Very Severe Cyclonic Storm crosses the coast near Kakinada, the weather warning maps show Odisha and Coastal Andhra Pradesh covered under identical high-level warnings. The system will dump phenomenal amounts of water.

·         Districts Implicated: Malkangiri, Koraput, Rayagada, Nabarangpur, Kalahandi, Kandhamal, Ganjam, Nayagarh, Khordha, Cuttack, Puri, and Jagatsinghpur.

·         Intensity: Extremely heavy rainfall exceeding 20 cm in specific areas. Strong gale-force winds will impact southern Odisha districts, while the rest of the state transitions into an intense, continuous downpour driven by a Precipitable Water (PWAT) value of nearly 3 inches in the regional atmospheric column.

Day 3: Thursday, October 29 (The Inland Dissipation Phase)

While the warning for Andhra Pradesh is downgraded as the storm's core structure begins to splinter due to high vertical wind shear (climbing up to 76 knots) and terrain friction, Odisha remains under a widespread heavy rainfall footprint. The remnant vortex of the storm will flatten and track northwestward directly across the state's interior.

·         Districts Implicated: Nuapada, Bolangir, Bargarh, Sambalpur, Sonepur, Boudh, Angul, Dhenkanal, Deogarh, and Jharsuguda.

·         Intensity: Heavy rainfall (7 to 11 cm) will shift from the coastal and southern belts into western and northwestern Odisha, comprehensively soaking the state before the moisture field expands into Chhattisgarh and Jharkhand.

Focus on the Twin Cities: Bhubaneswar and Cuttack

For the urban centers of Bhubaneswar and Cuttack, the three-day timeline poses a severe challenge to municipal infrastructure. Positioned within the Khordha and Cuttack districts respectively, the twin cities sit directly in the primary path of the storm's northern rain field.

·         The Rainfall Trigger: With the regional relative humidity sitting at a staggering 98% in the mid-lower troposphere, the air over the twin cities will be completely saturated. The arrival of the outer bands on late October 27 will trigger continuous, unrelenting rain that will peak on October 28. The total accumulated rainfall over the 72-hour period could easily exceed 25 to 30 cm in the metropolitan areas.

·         Urban Flooding Vulnerability: Because the rainfall is projected to be continuous rather than brief, low-lying areas in Bhubaneswar (such as Iskcon Temple road, Acharya Vihar, and Bomikhal) and ancient low-lying localities of Cuttack will face a high probability of severe waterlogging and flash urban flooding. Municipal bodies will need to ensure that storm drains and drainage channels (like the major natural storm channels in Bhubaneswar and the Kathajodi river sluice gates in Cuttack) are entirely clear of obstructions prior to October 27.

·         Wind and Disruption Risks: While the twin cities will be spared the catastrophic 100+ km/h gale winds predicted for the Kakinada landfall zone, the proximity to the cyclonic vortex will still bring sustained winds of 40 to 50 km/h, with gusts reaching 60 km/h on October 28. Combined with the water-softened soil, these wind speeds are sufficient to uproot weak trees, damage temporary structures, and cause localized power grid disruptions.

The Bottomline

Cyclone Arnab presents a textbook case of weather interplay. While the high-energy oceanic fuel reservoirs of the south-west Bay of Bengal are dictating the geographical target of the storm's destructive core winds near Kakinada, the massive 5.8 km vertical profile of the system guarantees that Odisha cannot escape its reach.

The three-day timeline issued by the IMD stands as a firm warning: from the initial coastal bands on October 27 to the widespread interior deluge on October 29, Odisha faces a prolonged test of its disaster preparedness, with the twin cities of Bhubaneswar and Cuttack sitting squarely in the path of the storm's historic moisture trail.

Also Read: EXCLUSIVE| Inside Cyclone Arnab’s Machinery: Why Ocean Dynamics Are Drawing Very Severe Storm to Andhra Coast over Odisha