EXCLUSIVE| IMD Forecast Reveals Fate of Oct 13 Low, Odisha to North Andhra sits Under Dry Zone this Durga Puja

Bhubaneswar: A new low-pressure area is poised to form over the Southeast Bay of Bengal within the next 48 hours.

Driven by highly favourable Sea Surface Temperatures (SST) of 31°C, the ocean is providing ample thermal fuel to seed and intensify this surface low. With the sacred Navratri festival commencing this Sunday, all eyes are pinned on how this system will pan out and whether it threatens the East Coast of India, including Odisha.

Alongside predicting the formation of the low-pressure area on October 13, the India Meteorological Department (IMD) has released a comprehensive weather outlook that signals a major shift in coastal dynamics. While the national forecaster is keeping a close watch on the system's birth in the Southeast Bay of Bengal, its extended charts reveal critical insights into the structure and longevity of the system during the 96 hours following its development.

While long-range simulations from the National Centre for Medium Range Weather Forecasting (NCMRWF) has been predicting a damp festive season across eastern India, the IMD's latest outlook through October 17 stands in sharp contrast.

 

The apex weather body's charts effectively let the East Coast off the hook for heavy rainfall, keeping Odisha relatively dry. Conversely, the data shows the system is primed to act as a potent catalyst for a heavy, widespread rainfall surge across South Peninsular India, putting Tamil Nadu, Kerala, and South Interior Karnataka on high alert.

Tracking the Southeast Bay Low

According to the official synoptic analysis released by IMD, the atmospheric setup over the Indian Ocean region is undergoing a structural transition typical of the mid-October post-monsoon phase.

The line of withdrawal of the Southwest Monsoon continues to cut through northern and central latitudes, passing precisely along 27.5°N / 86.5°E, stretching through Supaul, Ranchi, Sundargarh, Bargarh, Bijapur, Hyderabad, Belagavi, and Panjim down to the Arabian Sea axis at 15°N / 72°E.

As dry, continental air mass begins to establish dominance over northwest and central India, conditions have become highly favorable for the further retreat of the Southwest Monsoon from remaining pockets of East India and the Northern Peninsula. However, the vacuum left by the retreating monsoon is being filled by intense convective activity over the maritime zones.

The focal point of global weather agencies remains an upper air cyclonic circulation currently positioned over the Strait of Malacca, extending up to a significant height of 9.4 kilometers above mean sea level. Dynamic modeling indicates this robust system is moving westward and is highly likely to emerge into the Andaman Sea within the next 24 hours. Under its direct thermodynamic influence, a well-defined low-pressure area is predicted to consolidate over the Southeast Bay of Bengal on or around Tuesday, October 13.

Simultaneously, a complex network of troughs and cyclonic circulations continue to govern near-surface wind behavior across the peninsula.

A low-level trough persists from northwest Rajasthan to northeast Madhya Pradesh, while an upper air cyclonic circulation hovers over South Bangladesh and its neighborhood between 1.5 and 3.1 kilometers above mean sea level. Further south, an active circulation over the Gulf of Mannar and the adjoining South Tamil Nadu coast at 0.9 kilometers is maintaining a steady flux of moisture-laden maritime winds, ensuring that the southern tip of the peninsula remains highly unstable even before the Bay of Bengal system reaches maturity.

Odisha: A Massive Downgrade and Festive Relief

For weeks, a rumour has been blowing in the air thick and fast over the likely washout of Durga Puja celebrations in the State. Even the Puja committees across Odisha had been anxiously tracking whether the system bring heavy, disruptive rainfall during Durga Puja, which overlaps significantly with the October 15–21 window. Many puja committees have already implemented safeguards.

However, the IMD’s official 7 Days Rainfall Forecast has fundamentally revised this outlook, offering immense relief to organizers and pandal-hoppers alike.

The objective data presented by the IMD maps a gradual attenuation of rainfall probability over Odisha rather than an escalation during the Durga puja Period. Between October 11 and October 13, the state is under an ISOL (Isolated) rainfall status, indicating that only highly localized, brief showers will manifest, primarily driven by daytime heating and local convective clouds.

As the low-pressure system develops further south in the Bay of Bengal between October 14 and October 16, the moisture inflow triggers a minor step up to a SCT (Scattered) rainfall regime. This means that while some districts will experience passing rain, more than half of the meteorological stations across the subdivision are expected to remain completely dry at any given hour.

Date Range	IMD Predicted Category	Spatial Coverage Distribution	Potential Impact on Public Infrastructure
Oct 11 – Oct 13	Isolated (ISOL)	Less than 25% of stations recording rain	Negligible; dry conditions favor final puja pandal decorations.
Oct 14 – Oct 16	Scattered (SCT)	26% to 50% of stations recording rain	Minor interruptions; brief afternoon passing showers.
Oct 17	Downgraded to Isolated (ISOL)	Less than 25% of stations recording rain	Clear weather favoring late-evening festival gatherings.

Most critically, on October 17, right as the festive energy peaks, the IMD has officially downgraded Odisha’s status back to ISOL. This crucial development proves that the anticipated low-pressure area over the Southeast Bay of Bengal is keeping a highly southerly trajectory, failing to curve northward toward the Odisha landmass.

As the system tracks west-northwestward at a lower latitude, its outer bands will struggle to penetrate the northern East Coast, effectively sparing cities like Bhubaneswar, Cuttack, Puri, and Balasore from any prolonged or severe wet spells.

Andhra Pradesh: A Divided Coastal Narrative

The elongated geography of Andhra Pradesh means the state will experience a highly polarized response to the evolving low-pressure system. The IMD treats Coastal Andhra Pradesh and Rayalaseema as two distinct meteorological theatres, with the latter poised to absorb far greater atmospheric volatility.

For Coastal Andhra Pradesh, the forecast remains surprisingly muted given the proximity to a developing tropical depression. The region is marked under a persistent ISOL (Isolated) rainfall category from October 12 all the way through October 17. The lack of any upgraded warning levels suggests that the core of the low-pressure system will remain at a safe distance from the immediate coast of Visakhapatnam, Kakinada, and Nellore.

However, the IMD text bulletin adds a vital layer of nuance, warning that Strong Surface Winds are likely to sweep across Coastal Andhra Pradesh and the union territory of Yanam between October 11 and October 15. These gusty maritime winds, while not accompanied by torrential downpours, could present rough sea conditions, prompting caution for local fishing communities operating off the southern Andhra shelf.

Shifting inland to in AP, the weather pattern becomes distinctly more aggressive. Grounded by an expansive moisture pull from both the Bay of Bengal and the Arabian Sea, Rayalaseema maintains a steady ISOL to SCT profile throughout the week. More importantly, the synoptic analysis explicitly warns of isolated thunderstorms, lightning, and severe gusty winds peaking between 30–40 kmph (and occasionally hitting temporary bursts up to 50 kmph) through October 15. The interior districts of Anantapur, Chittoor, and Kadapa must therefore brace for sharp, sudden electrical storms that could pose sudden localized hazards despite the absence of an overarching regional deluge.

Tamil Nadu: The Epicenter of the South Peninsular Surge

As the northern states breathe a sigh of relief, the meteorological focus shifts squarely onto Tamil Nadu, Puducherry, and Karaikal, which are rapidly emerging as the primary landing zone for the moisture discharge associated with this double-ocean atmospheric coupling. Even prior to the full consolidation of the October 13 low-pressure area, Tamil Nadu is being heavily fed by the low-level easterly waves and the active cyclonic circulation sitting over the Gulf of Mannar.

The IMD’s spatial text bulletin categorizes the state under a continuous Isolated to Scattered rainfall mandate from October 11 through October 17, but emphasizes a significant escalation in intense localized events as the week advances. The forecast warns of isolated thunderstorms, lightning, and severe gusty winds reaching speeds of 40–50 kmph, with gusts maxing out at 60 kmph across Tamil Nadu and Puducherry from October 11 to October 15.

The analytical inflection point occurs between October 16 and October 17, as the primary low-pressure area pushes closer toward the southern peninsula. During this 48-hour window, the IMD has officially projected Isolated Heavy Rainfall over coastal and interior Tamil Nadu. The combination of strong surface winds and intense, short-duration convective cloud bursts means that urban centers, including Chennai, and sensitive agricultural zones in the delta region will need to closely monitor drainage systems to counter potential localized waterlogging.

Analytical Assessment: Why the West Coast Steals the Storm

An elegant revelation within the IMD's multi-day outlook is the dramatic shift of severe weather toward the West Coast of India, specifically Kerala and Coastal Karnataka. While a low-pressure area is birthing in the Bay of Bengal (East Coast), the structural mechanics of the peninsular wind flow are forcing an intense convergence zone directly over the Arabian Sea side.

• The Southern Catalyst: A fresh Low Pressure Area consolidates over the Southeast Bay of Bengal around October 13, sending massive columns of tropical moisture northward.
• The Northern Shield: Simultaneously, Dry Continental Air pushes south behind the retreating monsoon, acting as an atmospheric barrier across central India.
• The Peninsular Funnel: Trapped between these systems, the wind flow is forced into a tight Peninsular Convergence Zone, driving moisture aggressively from east to west across the southern tip of India.
• The Divergent Impact:

o    East Coast (Odisha): Stranded on the stable, outer periphery of the system, the state escapes with only Isolated (ISOL) showers and minimal festive impact.

o    West Coast (Kerala): Smashed by the full brunt of the channeled moisture hitting the Western Ghats, the region braces for an intense, Widespread (WS) heavy rain surge.

 

The IMD’s 7-day table underscores this perfectly: while Odisha drops to isolated showers by October 17, Kerala scales up exponentially to FWS (Fairly Widespread) on October 15 and hits absolute WS (Widespread) coverage on October 16 and 17. Concurrently, South Interior Karnataka jumps to Widespread rain by the tail-end of the week.

This indicates that the peninsular landmass is acting as a massive meteorological ramp. The moisture drawn in by the Bay of Bengal low is being pulled rapidly across the southern states, encountering the high topographic barrier of the Western Ghats. As these warm, moisture-laden easterly winds smash into the mountain range, they are forced to rise abruptly, leading to massive orographic lifting and intense cloud condensation.

Consequently, the most severe, relentless rainfall yields are dumped directly over Kerala and coastal Karnataka, leaving the northern East Coast (Odisha and Northern Andhra Pradesh) under a relatively dry, stable rain shadow zone.

Also Read: EXCLUSIVE | IMD Signals Low Pressure on Oct 13: 160mm Rain for Andhra & Chennai, Cool Overcast Skies for Puja Revellers in Odisha Bhubaneswar