Will this streak continue into NEM 2025? - NEM 2025 Inference !!!!

 

North East Monsoon 2025 Outlook – MasRainman (RainmanStudio)
(Personal Forecast – For official updates, please follow IMD and government agencies.) 

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🌧️ Introduction

We are entering the 5th consecutive strong North East Monsoon (NEM) season since 2020 — following the highly successful years of 2020, 2021, 2022, 2023, and 2024.

The Southwest Monsoon 2025 was an exceptional season, driven by a neutral-to-La Niña transition along with a Neutral IOD to negative IOD, resulting in widespread rains across India.

Nearly 95–97% of Tamil Nadu’s districts recorded normal to above-normal rainfall from June to September, ranking 2025 among the Top 4 wettest years in Tamil Nadu’s monsoon history.

Now, the question remains — will this streak continue into NEM 2025?

Vi deo Explanation : https://youtu.be/sAw5IKkTEng

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🔍 NEM 2025 – Key Atmospheric Drivers
This year’s analog pattern closely resembles 2005 and 2020, 1996, both excellent monsoon years for the region.

1️⃣ ENSO & IOD Setup

• ENSO is leaning toward La Niña, evolving from a neutral (Nina-like) base state.

• IOD remains strongly negative, favouring enhanced convection near the equatorial Indian Ocean.

• The combination supports frequent system formation in the Bay of Bengal.

2️⃣ MJO, ER & Kelvin Wave Trends

• The MJO (VP200), Equatorial Rossby (ER), and Kelvin wave structures are showing analog similarities with 2005 and 2020.

• Expected MJO phases 2, 3, and 4 during mid to late October may enhance the NEM onset.

• A fresh MJO pulse in November could further strengthen rainfall activity, especially with a La Niña–Negative IOD base state.

3️⃣ QBO (Quasi-Biennial Oscillation)

• Current Status (October 2025): QBO index at −5.26 m/s (50 hPa) — indicating an easterly phase.

• Impact: The easterly QBO tends to enhance WNW movement of systems and may increase curvature potential of cyclones, leading to more frequent and slightly stronger systems.

4️⃣ AO & Western Disturbance Influence

• Arctic Oscillation (AO) remains weak, suggesting limited WD intrusions during early NEM.

• From mid-November to December, WD activity may dip into lower latitudes, potentially aiding rainfall in northern Tamil Nadu and Andhra Pradesh.

5️⃣ ITCZ & Latitudinal Shift

• The ITCZ currently lies north of its climatological position, expected to descend later in the season.

• This may initially favor North TN–South AP–Central AP regions for enhanced rainfall, before shifting southward in December.

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🌊 SST & System Formation

• Bay of Bengal SSTs are in the 28–30°C range — highly favorable for cyclogenesis.

• Expected outcomes:

• 2 Cyclones (marginal to moderate strength)

• 2–3 Depressions

• 2–4 Low Pressure Areas (LPA)

• Several trough-based circulations

Due to La Niña background and strong negative IOD, MJO episodes may remain weak, producing more frequent but moderate-intensity systems rather than intense cyclones.

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🌀 Expected Tracks

• Most systems likely to track NW/WNW, with occasional curvature due to easterly QBO dynamics.

• Standing Wave (STW) conditions, similar to 2020, could emerge again.

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📅 NEM Onset Expectation

• Probable Onset: Around October 16–18 ±4 days.

• Early November could see active phases as MJO energy peaks in the Indian Ocean.

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🌧️ Regional Rainfall Outlook (NEM 2025)

Region	Expected Rainfall	Remarks
North TN & Delta Region	🌧️ Excess	More cyclonic tracks and WNW systems
South TN	🌧️ Normal to Excess	Depends on low-latitude system movement
Interiors (Western & NW TN)	🌧️ Normal to Excess	Some Bay systems may cross into Arabian Sea

Overall, Tamil Nadu is expected to experience Normal to Excess rainfall, continuing the positive monsoon run for the South Peninsula.
 
 

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📍 Highlights for KTCC & North Coastal TN
The KTCC belt – Chennai, Kanchipuram, Thiruvallur, Chengalpattu, Pondy, Viluppuram – is expected to record excess monsoon rainfall this year, contingent on system tracks and MJO phasing.

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Kerala OND Outlook

Region	OND 2025 Expected Rainfall vs Normal	Remarks
South Kerala (Thiruvananthapuram, Kollam, Pathanamthitta)	Near to slightly above normal (+0 to +10%)	Weaker October balanced by active November storms.
Central Kerala (Alappuzha, Kottayam, Ernakulam, Idukki)	Near normal (±5%)	Convective rains during November offset dry October.
North Kerala (Thrissur, Palakkad, Malappuram, Kozhikode, Wayanad, Kannur, Kasaragod)	Slightly above normal (+10–20%)	November wetter than average; OND cumulative positive anomaly.

 
Karnataka OND Outlook

Region	OND 2025 Expected Rainfall vs Normal	Remarks
Coastal Karnataka (Udupi, Mangalore, Uttara Kannada)	Near to slightly above normal (0 to +10%)	Recovery in November after weak October.
Malnad Region (Kodagu, Chikkamagalur, Hassan, Shivamogga)	Near normal (±5%)	Balanced pattern; orographic support helps November totals.
South Interior Karnataka (Bengaluru, Mysuru, Mandya, Ramanagara, Tumakuru)	Near normal (−5 to +5%)	Occasional NE Monsoon spillovers in Oct–Nov.
North Interior Karnataka (Belagavi, Ballari, Raichur, Kalaburagi, Bidar)	Below normal (−10 to −25%)	Drier trend continues; limited NEM impact.

 

Andhra Pradesh OND Outlook

Region / District	OND 2025 Expected Rainfall vs Normal	Remarks
South Coastal AP (Nellore, Tirupati, Chittoor, SPSR Nellore)	Above normal (+10 to +25%)	Strong easterlies and early NEM systems; wet Oct–Nov.
Central Coastal AP (Prakasam, Guntur)	Slightly above normal (+5 to +15%)	Good October spells, easing by December.
North Coastal AP (Krishna, West/East Godavari, Visakhapatnam, Vizianagaram, Srikakulam)	Near normal (±5%)	Moderate NEM activity; fewer November systems.
Rayalaseema interior (Kurnool, Anantapur, Kadapa)	Near to slightly below normal (−5 to +5%)	Patchy rainfall; benefits mainly in October.

 
✅ Andhra Pradesh Summary:

• South coastal belt: clearly wetter than normal.

• Central & north coastal: near normal.

• Rayalaseema: Normal & Dry  by December.

🌡️ Early-active NEM, moderate finish; OND total roughly 100–110 % of normal to Above Normal statewide.
 
  
Telangana OND Outlook

Region / Zone	OND 2025 Expected Rainfall vs Normal	Remarks
Southern Telangana (Mahabubnagar, Nagarkurnool, Nalgonda)	Slightly below normal (−5 to −10%)	Limited spillover from Rayalaseema easterlies.
Central Telangana (Hyderabad, Rangareddy, Vikarabad, Medak)	Below normal (−10 to −20%)	Weak post-monsoon activity; dry October–December.
Northern Telangana (Adilabad, Nizamabad, Karimnagar, Warangal, Khammam)	Below normal (−10 to −25%)	Early retreat of SWM, minimal NEM influence.

✅ Telangana Summary:
Mostly below-normal rainfall, especially over northern half.
🌤️ October provides isolated showers; November–December largely dry.
  Andhra Pradesh (overall): Normal to slightly above normal (100 – 110 % of normal).
  Telangana (overall): Below normal (80 – 90 % of normal).
 
 
🌦️ Summary
✅ 2025 NEM driven by Negative IOD + La Niña base state
✅ Easterly QBO supports frequent system formation
✅ MJO & Kelvin activity favorable during onset & mid-season
✅ Onset expected mid-October
✅ Overall: Normal to Excess NEM for Tamil Nadu & South Peninsula,Kerala Karnataka AP & Telangana.

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