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.
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 .
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 15th 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.
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 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 15th 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.
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