Bhubaneswar: Is Odisha heading into an unusually tricky October weather transition this year?

On one side the Odisha Revenue and Disaster Management Minister Suresh Pujari Thursday hinted an early withdrawal of the southwest monsoon saying, it could expose the state to a sudden spell of oppressive, humid “second summer” or October heat.

On the other is the latest North Carolina Institute for Climate Studies (NCICS) atmospheric signal, which points towards a strong convective phase of the Madden-Julian Oscillation (MJO) entering the Indian Ocean during the first week of October.

That distinction matters.

A premature monsoon retreat would favour clearer skies, stronger solar heating and a rapid rise in daytime heat. But if the atmosphere simultaneously retains a strong tropical convective signal, Odisha and the Bay of Bengal could instead see renewed moisture, low-pressure development and an enhanced late-season cyclogenesis environment.

The result is not necessarily a choice between “summer” and “cyclone”.

October could potentially deliver both – but at different stages of the transition.

The latest NCICS forecast shows persistent convective activity through mid-September, a delayed weakening of the monsoon regime towards late September and then a renewed, deep convective signal around September 30–October 6.

That creates an important meteorological question for Odisha: What happens if the monsoon begins withdrawing early, but the tropical atmosphere refuses to switch off?

The Two October Scenarios
The Minister’s warning and the NCICS signal are actually describing two different parts of the atmospheric transition.

Weather signal	What it means for Odisha	Likely consequence
Early monsoon withdrawal	Rainfall and cloud cover decline earlier	Rapid heating
Wet soil left behind by monsoon	Moisture remains close to the surface	High humidity
Clear skies after withdrawal	More direct solar radiation reaches land	Day temperatures rise
Weak/stagnant winds	Heat and moisture remain trapped	Higher heat index
Active MJO in Indian Ocean	Deep tropical convection and moisture increase	Greater low-pressure potential
Active MJO + favourable Bay conditions	Reduced shear and enhanced atmospheric spin	Cyclogenesis risk rises
Delayed withdrawal	Persistent cloud/rain suppresses immediate heat	Cooler but wetter transition
Withdrawal followed by clear skies	Heat builds rapidly	“October summer”

So the real uncertainty is not whether one forecast is right and the other wrong.

It is whether the atmosphere manages to transition cleanly from the southwest monsoon into the post-monsoon regime – or whether the transition becomes compressed, volatile and punctuated by tropical disturbances.

What the NCICS forecast is actually showing

The latest seven-day OLR outlook cited in the inputs provides an important clue.

Outgoing Longwave Radiation is a useful indicator of deep convection. Negative OLR anomalies generally indicate enhanced cloudiness and convection, while positive anomalies are associated with suppressed convection and clearer, drier conditions.

The NCICS sequence shows three broad stages:

Period	NCICS signal	What it suggests
Sept 9–22	Persistent cloud formation	Active convection remains
Sept 23–29	Increasing dry suppression over parts of India	Monsoon transition begins
Sept 30–Oct 6	Deep convective/MJO signal over Indian Ocean and southern peninsula	Tropical activity potentially re-energises

The most striking part is the late September–early October reversal.

The atmosphere may begin moving towards a drier post-monsoon structure, but an active MJO pulse could arrive just as that transition is underway.

That is why the first week of October deserves attention.

Why the MJO matters to the Bay of Bengal

The Madden-Julian Oscillation is not a cyclone by itself.

It is a large-scale tropical wave of enhanced and suppressed convection that travels eastward around the equatorial region.

But when its active convective phase reaches the Indian Ocean during the post-monsoon cyclone season, it can create a more favourable background environment for tropical disturbances.

A research notes that October is already the peak of the North Indian Ocean’s post-monsoon cyclogenesis season and identifies MJO phases 1, 2 and 3 over the Indian Ocean as particularly important.

The atmospheric mechanism described in the inputs is straightforward:

Active MJO → more tropical convection → enhanced low-level vorticity + reduced vertical wind shear → greater potential for organisation and rapid intensification.

The study summary says rapid-intensification episodes were about four times more frequent when the MJO was active over the Indian Ocean in phases 1–2 than when it was positioned over the Pacific in phases 6–7.

That does not mean a cyclone is inevitable.

It means the background environment can become substantially more supportive if a suitable low-pressure disturbance forms.

The October contradiction: heat outside, cyclone fuel inside

This is where Odisha's October story becomes complicated.

The classic “October heat” mechanism needs:

clear skies + wet land + intense solar radiation + high humidity + weak winds.

The cyclone mechanism, meanwhile, benefits from:

warm ocean + deep convection + atmospheric moisture + low vertical wind shear + sufficient low-level rotation.

These conditions can coexist during a transitional month.

The land can begin drying and heating after monsoon withdrawal while the Bay of Bengal remains warm and dynamically active.

Therefore, an early withdrawal does not automatically mean a calm October.

It can instead produce a rapid transition in which:

1. the land begins heating;

2. humidity remains high;

3. tropical moisture remains available;

4. an MJO pulse enhances convection over the Indian Ocean;

5. a low-pressure area develops over the Bay;

6. atmospheric conditions determine whether that system weakens, intensifies or moves towards the coast.

Odisha’s own history shows why October cannot be read from one signal

The historical IMD data available for Odisha shows that the monsoon's final withdrawal has varied substantially from year to year.

The normal window identified has been October 10–15, but several years have seen withdrawal substantially later.

Odisha: 15-year monsoon withdrawal and October heat matrix

Year	Final withdrawal from Odisha	October daytime maximum	Weather character
2025	Oct 15–17	32–34.5°C	Sudden clearing and high heat index
2024	Oct 18–19	33–36°C	Extremely warm October; warm nights
2023	Oct 19	32.5–34°C	About 1.5°C above normal
2022	Oct 22–23	32–34°C	Delayed retreat, humidity spike
2021	Oct 24–25	31.5–33°C	Very delayed transition
2020	Oct 26–28	33–35°C	Highly delayed retreat
2019	Oct 16–17	32.5–34.5°C	Rapid post-monsoon warming
2018	Oct 21	32–34°C	Late high-pressure build-up
2017	Oct 17–19	31.8–33.5°C	Humid “second summer”
2016	Oct 28	33–35.5°C	Monsoon lingered unusually long
2015	Oct 29	32.5–34°C	Delayed withdrawal
2014	Oct 18	32–33.8°C	Slightly late withdrawal
2013	Oct 23–24	31–33°C	Cyclone Phailin disrupted October heat
2012	Oct 18	32–34°C	Severe heat after clearing
2011	Oct 13–14	31.5–32.5°C	Closest to normal baseline

Source: IMD-based historical dataset

The historical lesson: October has two personalities

The table reveals something important.

October heat is not simply a consequence of an early monsoon withdrawal.

Odisha has experienced oppressive heat even after late withdrawals, because the delayed monsoon can leave enormous quantities of moisture over the land. Once the clouds clear, that moisture can turn into a powerful humidity-driven heat index.

The historical data places the long-term October daytime maximum baseline around 31.5–32°C, while recent Odisha observations in key areas frequently reach 33–36°C.

That explains why the Revenue Minister's warning cannot be dismissed simply because the monsoon might not disappear immediately.

The question is what happens immediately after the clouds and rain retreat.

Why wet soil can make October feel like summer

The October heat mechanism, however, is different from May's dry heat.

In May, the atmosphere and land are generally much drier.

After the monsoon, however, the ground can remain saturated.

When clear skies return, intense solar radiation heats the land.

That heat drives evaporation.

The sequence becomes:

Direct sunlight → evaporation → rising humidity → reduced sweat evaporation → higher apparent temperature.

Thus, a thermometer reading of around 33°C can feel considerably hotter when humidity is very high.

This is the “sauna effect” behind the phrase October Heat.

But the Bay follows a different clock

While Odisha's land surface may be moving towards a hotter, drier regime, the Bay of Bengal does not necessarily make the transition at exactly the same time.

October is historically a major post-monsoon cyclone month.

The NCICS identifies the southeastern Bay/Andaman Sea region as an important genesis area, broadly around 8°N–14°N and 85°E–95°E, where a developing system can obtain a long stretch of warm ocean over which to organise.

This is particularly significant if the MJO's active convective phase is present.

A system developing farther south and east can have a longer oceanic runway before approaching the Indian coastline.
And then comes the track question

Even if an October low-pressure system develops, development does not automatically mean an Odisha landfall.

The ultimate destination depends on the larger atmospheric steering pattern, particularly the subtropical ridge and upper-air circulation.

Historical data analysis identifies three broad possibilities:

Track	Basic movement	Potential impact zone
A — Northwest	Andaman/southeast Bay → central Bay → northwest	Odisha / West Bengal
B — Recurving north	Central Bay → north/northeast	West Bengal / Bangladesh / Myanmar
C — Westward	Bay → west or west-southwest	Andhra Pradesh / Tamil Nadu

Track A is particularly relevant to Odisha because a system moving northwest from the central or southeastern Bay can approach the Odisha coast.

Historical examples are Cyclone Dana in 2024 and Cyclone Phailin in 2013 for broad northwestward Odisha-facing track structures.

But this remains a conditional risk, not a forecast of an October cyclone.

Dana 2024: a reminder of the October equation

Cyclone Dana provides a recent Odisha example of how the October atmosphere can rapidly become complicated.

The IMD historical data shows that operational outlooks during October 2024 highlighted an MJO Phase 3 signal with strong amplitude, while a low-pressure system was developing over the central Bay.

That system eventually intensified into Severe Cyclonic Storm Dana and moved towards the Odisha-West Bengal coast.

Interestingly, the year 2024 began with peak El Nino in Jan 2024, and by October, the ENSO turned neutral. IMD historical data records 2024 October as the hottest in Odisha and India, just as Min Suresh Pujari is hinting at Oct 2026.

The significance for 2026 is not that another Dana is coming.

There is no basis in the supplied NCICS signal to make that claim.

The lesson is narrower:

When the October tropical background becomes favourable, a low-pressure system that might otherwise struggle can find a much more supportive atmospheric environment.

Only when several of these signals line up can the risk of a significant cyclone begin to become clearer.

The real October dilemma for Odisha

The Minister's warning therefore represents one side of the transition.

If the monsoon withdraws prematurely and the atmosphere clears rapidly, Odisha could experience the classic sequence:

Early retreat → intense sunlight → wet soil → evaporation → high humidity → October heat.

But the NCICS signal introduces a second possibility:

Late September transition → active MJO arrives → renewed convection → low-pressure formation potential → enhanced Bay cyclogenesis environment.

And these two processes do not necessarily contradict each other.

They can occur within the same fortnight.

That is precisely what makes the first week of October worth watching.

The bigger picture: Odisha may not get a clean seasonal handover

The historical record shows that Odisha's monsoon withdrawal has repeatedly moved deep into October, while October temperatures have also frequently risen above the long-term baseline.

At the same time, the NCICS outlook points to a potentially active tropical phase around September 30–October 6.

So the state's October problem may not be simply:

“Will summer return early?”

Nor is it yet:

“Will another cyclone hit Odisha?”

The more scientifically defensible question is:

Will Odisha experience a compressed and unstable transition – with land heating rapidly even as the Bay remains capable of producing late-season disturbances?

For now, the evidence supports heightened monitoring rather than a cyclone prediction.

The next decisive signals will come from the actual monsoon withdrawal, the evolution of the MJO, and whether a genuine low-pressure area emerges over the Bay during the early-October window.

Bottomline: Odisha could be caught between two atmospheric clocks this October – the retreating monsoon clock over land and the MJO-driven tropical clock over the Indian Ocean and Bay of Bengal. If the first accelerates while the second remains active, the state could see a volatile transition in which “October summer” and cyclone risk become two sides of the same seasonal change. 
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