Detailed Monsoon Watch 3 below Abridged Note

🌦️ Abridged Monsoon Watch – 3 (2025):  (As on 2nd May)

1. Cross Equatorial Winds – 🟩 Normal

Winds are active in both Arabian Sea and Bay sectors; Somali SSTs still warm (30°C). Bay branch has UAC; needs further organization.
Indicator: 🟩 Normal

2. Seasonal Low (Thar Region Core Heat) – 🟥 Negative

Heating paused; core pressure still high at ~1004 mb. Needs to drop for effective pressure gradient formation. Core required at 994 mb in June to create Monsoon pull Gradient.
Indicator: 🟥 -ve

3. ENSO Status – 🟨 Neutral

ONI at -0.4, SOI at -1.7 – within neutral range. No El Niño or La Niña signals active.
Indicator: 🟨 Neutral

4. Bay of Bengal Activity – 🟥 Negative

No signs of low or storm development yet. SSTs are favorable but no trigger seen.
Indicator: 🟥 -ve

5. ITCZ / Line of Wind Discontinuity (LWD) – 🟩 Normal

Positioned near equator; LWD from Maharashtra to Kerala present. Pre-monsoon activity still weak but expected to improve.
Indicator: 🟩 Normal

6. Jet Streams (200 hPa) – 🟥 Negative

Still weak and south-easterly south of 8°N. Needed: easterlies to support Monsoon flow into Andamans.
Indicator: 🟥 -ve

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✅ Parameter Summary Table (with Color Codes)

Parameter	MW-1	MW-2	MW-3
Cross Eq. Winds	🟩 Normal	🟩 Normal	🟩 Normal
Seasonal Low (Heat)	🟩 +ve	🟥 -ve	🟥 -ve
ENSO	🟨 Neutral	🟨 Neutral	🟨 Neutral
Bay Low	🟩 +ve	🟥 -ve	🟥 -ve
ITCZ / LWD	🟩 Normal	🟩 Normal	🟩 Normal
Jet Streams (200 hPa)	⬜ –	⬜ –	🟥 -ve
Overall	🟧 Slight -ve	🟥 -ve	🟨 Normal

Legend:

• 🟩 Positive/Normal

• 🟥 Negative

• 🟨 Neutral

• 🟧 Slightly Negative

• ⬜ Not Applicable / Not Active Yet

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📆 Tentative Monsoon Onset Dates (Based on Current Indicators)

• South Andamans: 19th May

• Andaman Islands: 22nd May

• Maldives: 26th–27th May

• Sri Lanka: 29th–30th May

• Kerala / NE States: 1st–3rd June

• Coastal Karnataka: 7th June

• Goa: 8th–9th June

• Mumbai & West Bengal: 12th–14th June

⚠️ Note: This is an observation-based forecast. Not for commercial use. Conditions may change quickly and are monitored in real-time.

Monsoon Watch – 3 ...2025 .....2nd May

Further Analysis of the parameters as discussed in MW-1,MW-2.

Position as on 2nd May :

1.Cross Equatorial Winds :
Let me explain, that the winds on crossing the equator break into 2 branches. i) gushing into the Arabian Sea, and ii) moving into the Bay of Bengal. 

Wind flow on 1st May 2025

i) In the Western sector Southern Hemisphere, winds are just picking up speed and hitting the East African coast, and  re-curving formation is seen. To get a defined Somali Current, we need a proper re-curving Northwards/North-East of the winds, on the Kenyan coast. 

The current SST off the Somali Coast is 30 c (above normal),while the required SST in first week of June is 19/20c. (Required to form masses of Monsoon clouds in the warm central Arabian Sea).

ii) In the eastern sector, in the Bay Branch, the cross equatorial winds are currently in a UAC .

We prefer the Bay Branch to be better organised, as the normal date for SWM to hit the South Andaman Sea is 15^th May.

Indicator: Normal

Mascarene high pressure zone in the South Indian Ocean.

Main High reading of 1035 mb and other highs of 1024 mb are currently observed between Madagascar and Australia.

The "Power House" of the Monsoon winds is stable in strength (should be 1032 mb), for this time of the season.

Indicator: +ve. 

 2. Seasonal Low: 

The NW plains heating picked up initially, but stabilised again.

After the early summer onslaught, the heat decreased a bit over the North and west subcontinent between MW-2 and, MW-3 period. Gujarat and Central India went through a heat wave.

Past 7 days anomaly -

North ,west ,central India was in the warm/hot range.

Min temp was in the  normal range.

The seasonal Low, as a result has not improved. Had shown good progress during MW 2.

The pressure in the core region (Thar Desert / Sindh) is just touching 1004 mb. (In 2014 was 1004 mb, 2015 was 1000/1002 mb , 2016 it was at 1002 mb during this time). 

As mentioned, it normally should reach a low nadir of 994 mb in June in the Thar Desert, and with 1008 mb in the South Arabian Sea, a perfect gradient is created to attract the south -west winds towards the coast.

Indicator:-ve. 

3. ENSO: ENSO-neutral conditions are present.* Equatorial sea surface temperatures (SSTs) are near-average across most of the Pacific Ocean. ENSO-neutral is favored during the Northern Hemisphere summer, with a greater than 50% chance through August-October 2025.

 

I.O.D

30 day SOI has fallen further after MW2 and is now at  -1.7. ( sustained SOI of -7 to 7 is neutral. Above 7 is La Nina, and below -7 is El Nino ).

The Oceanic Nino Index (ONI) is based on SST departures from average in the Niño 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO.

 ONI has decreased marginally after MW2 and latest value is  -0.4.

( ONI of -0.5 to 0.5 is neutral. Above 0.5 is El Nino, and below -0.5 is La Nina).

Indicator: Neutral

4. The Bay

As discussed, we should normally see a low sometime after the 15th of April.

[( 2019 Feedback):A low pressure area had formed over east Equatorial Indian Ocean & adjoining Southeast Bay of Bengal  on 25th and it had become a Well Marked Low pressure area over the same region during subsequent three hours. It concentrated into a Depression over the same region in the morning on 26th April 2019 and intensified further into a Deep Depression on 27th April 2019. It intensified in to a Cyclonic Storm 'FANI' on 28th th April 2019 and into a Severe Cyclonic Storm in the evening of 29 . It further intensified into a Very Severe Cyclonic Storm in the early morning of 30th April, 2019 and further into an Extremely Severe Cyclonic Storm in the 30th April 2019.

Fani crossed the coast near Puri (Odisha) on 3rd May.]

2025: What is needed now is a pulse from the Far East. But, currently there is no storm or low pressure in the Philippines’ Seas.

 Another factor, which helps the winds gain strength, and bring more moisture into the Indian landmass, is the sea temperatures on both sides of the Peninsula. Optimum (warm) temperatures will hasten and create more clouds, and help in faster forming of the lows from the Bay.

Currently, the only sort of  sign is the normal temps (29/30 c) of the seas surrounding the peninsula. But sea temps (30c) near the South Andaman Sea are higher.

We prefer the Bay parameters to show fast progress, as the normal date for SWM to hit the South Andaman Sea is 15^th May.

Indicator: -ve

5. ITCZ / LWD :

To bring the existing SE winds above the 

equator (as SW) , the ITCZ should move 

northwards. Currently it is near the equator. 

During late April , it oscillated between equator 

to 5N.

A LWD in the central peninsula region "looks 

after" the moisture content in the interior 

areas, and prepares the atmosphere with the 

humidity required. In reality, this LWD 

remains till June, in variable phases, and 

finally merges with the Monsoon trough (axis)/ITCZ  when the ITCZ moves towards the 

Sub Continent.

Currently, the weak line of wind dis-

continuity is located as a trough, through the 

peninsula, from Madhya Maharashtra towards Kerala.

Outbreaks of pre- monsoon thunder showers 

which are expected normally in the southern 

states and South Maharashtra, are not in full vigour yet.

Indicator: Normal

6.Jet Streams :

The 200 hpa Jet streams over the subcontinent is the 

additional parameter to be watched from MW-3 .

The jet streams are to be followed as the westerly jet core 

shifts to the north and easterly jet stream is formed, over 

the course of late summer, progressively from south to 

north of the subcontinent , heralding the progress of 

south-west monsoon over the subcontinent.

Currently are weak south-easterly, south of 8 N latitude.

They are required to strengthen to easterlies at those 

latitudes in the coming days, for heralding the SWM to the 

South Andaman Sea.

The westerly jet core shifts north of the 

Himalayas during the southwest monsoon 

season, as the jet streams turn easterly over 

the subcontinent.

So, overall, we can summarize as:

PARAMETER	MW-1	MW-2	MW-3
1) Cross Eq.Winds	Normal	Normal	Normal
2) Seasonal Low	+ve	-ve	-ve
3) ENSO	Neutral	Neutral	Neutral
4) Bay Low	+ve	-ve	-ve
5) ITCZ	Normal	Normal	Normal
6) Jet Streams	-	-	-ve
Overall	Slightly -ve	-ve	Normal

*But, situations can change fast, and by the time we discuss the next  MW, some factors can suddenly become +ve or -ve. So, MW discusses and follows the developments as they emerge, and discuss the parameters as is where are.

Looking at the current parameters, there seems a normal date arrival in the South West Monsoon arrival dates for Andaman and Kerala as of now. 

South Andamans: 19th May

Andamans Islands : 22nd May

Maldives:  26th/27th May 

Sri Lanka: 29th/30th May

Kerala &NE States: 1st June/3rd June.

Coastal Karnatak: 7th June

Goa 8th/9th June

Mumbai  & West Bengal: 12th/14th June.

Monsoon Watch should not be used/depended upon commercially or otherwise. Monsoon Watch Series may differ from other models.