Gokul Tamilselvam
@gokultamilselvam.bsky.social
Project Scientist 2, Indian Institute of Tropical
Meteorology, Pune, India. Interested in tropical dynamics, Monsoons and Clouds, Tropical Cyclones.Views are my own.
Meteorology, Pune, India. Interested in tropical dynamics, Monsoons and Clouds, Tropical Cyclones.Views are my own.
October 19, 2025 at 4:51 AM
Analyses and interpretations here are mine alone as an attempt to understand tropical weather and climate processes. Images sourced from @TropicalTidbits @Indiametdept @meteoblue NOAA-CPC
October 19, 2025 at 4:46 AM
Analyses and interpretations here are mine alone as an attempt to understand tropical weather and climate processes. Images sourced from @TropicalTidbits @Indiametdept @meteoblue NOAA-CPC
This could eventually lead to an uptick in the genesis of synoptic scale low pressure systems as well over the oceanic regions.
October 19, 2025 at 4:46 AM
This could eventually lead to an uptick in the genesis of synoptic scale low pressure systems as well over the oceanic regions.
Global Numerical Weather Prediction Models on the medium range period, indicate that more such ER waves could form and propagate along the equatorial Indian ocean in the days to come as an MJO signal is about to constructively interfere with the low frequency signal.
October 19, 2025 at 4:46 AM
Global Numerical Weather Prediction Models on the medium range period, indicate that more such ER waves could form and propagate along the equatorial Indian ocean in the days to come as an MJO signal is about to constructively interfere with the low frequency signal.
A source region for several eastward and westward propagating moist equatorial waves. Currently, an ER wave is seen propagating westwards over the central equatorial Indian Ocean, whose northern part is causing widespread rainfall in the southern states of India including Tamil Nadu.
October 19, 2025 at 4:46 AM
A source region for several eastward and westward propagating moist equatorial waves. Currently, an ER wave is seen propagating westwards over the central equatorial Indian Ocean, whose northern part is causing widespread rainfall in the southern states of India including Tamil Nadu.
Along with these seasonal shifts that is taking place in the background, the region of anomalous enhanced tropical convection, especially the low frequency component continues to be dominated by a La Nina/ Negative IOD signal over the Maritime Continent and the Eastern equatorial Indian Ocean
October 19, 2025 at 4:46 AM
Along with these seasonal shifts that is taking place in the background, the region of anomalous enhanced tropical convection, especially the low frequency component continues to be dominated by a La Nina/ Negative IOD signal over the Maritime Continent and the Eastern equatorial Indian Ocean
All these changes have led to the withdrawal of the wet summer monsoon rainy season from over a larger part of India and a simultaneous start of the north east monsoon rainfall season over the south east peninsular India.
October 19, 2025 at 4:46 AM
All these changes have led to the withdrawal of the wet summer monsoon rainy season from over a larger part of India and a simultaneous start of the north east monsoon rainfall season over the south east peninsular India.
Also, one can note the associated sign reversal in the pole to equator ward temperature gradient over the south Asian region which is in association with the southward migrating quasi-stationary atmospheric heat source during this time of the year.
October 19, 2025 at 4:46 AM
Also, one can note the associated sign reversal in the pole to equator ward temperature gradient over the south Asian region which is in association with the southward migrating quasi-stationary atmospheric heat source during this time of the year.
This shift includes a major change in the structure of the atmospheric column from a Baroclinic atmosphere that prevailed during the boreal summer monsoon season to a Barotropic/Equivalent Barotropic atmosphere which is currently observed.
October 19, 2025 at 4:46 AM
This shift includes a major change in the structure of the atmospheric column from a Baroclinic atmosphere that prevailed during the boreal summer monsoon season to a Barotropic/Equivalent Barotropic atmosphere which is currently observed.
In addition to this, barotropic instability can help spin up synoptic scale systems such as a monsoonal low/depression which could bring in widespread heavy rains over central India as well.
June 8, 2025 at 5:13 PM
In addition to this, barotropic instability can help spin up synoptic scale systems such as a monsoonal low/depression which could bring in widespread heavy rains over central India as well.
In the days to come, this wave could constructively interfere with the developing background monsoon large scale circulation resulting in the amplification of monsoonal semi permanent features which would help monsoon advance towards north, central and eastern Indian states.
June 8, 2025 at 5:13 PM
In the days to come, this wave could constructively interfere with the developing background monsoon large scale circulation resulting in the amplification of monsoonal semi permanent features which would help monsoon advance towards north, central and eastern Indian states.
NWP models indicate an equatorial Rossby wave response likely emanating out from this off-equatorial anomalous heat source that could propagate north and west.
June 8, 2025 at 5:13 PM
NWP models indicate an equatorial Rossby wave response likely emanating out from this off-equatorial anomalous heat source that could propagate north and west.
Images sourced from @ECMWF @TropicalTidbits . Analysis and interpretations here are mine alone and for official forecasts please follow the respective national weather forecasting agencies. @Indiametdept
May 30, 2025 at 9:13 AM
Images sourced from @ECMWF @TropicalTidbits . Analysis and interpretations here are mine alone and for official forecasts please follow the respective national weather forecasting agencies. @Indiametdept
This would be replaced by suppressed rainfall and circulation anomalies during the first fortnight of June bringing in dry conditions. Most global NWP models are quite confident about the hiatus situation in the days to come.(3/3)
May 30, 2025 at 9:13 AM
This would be replaced by suppressed rainfall and circulation anomalies during the first fortnight of June bringing in dry conditions. Most global NWP models are quite confident about the hiatus situation in the days to come.(3/3)
A series of westward propagating equatorial Rossby waves that were interacting with the developing background monsoonal circulation to enhance rainfall and accentuating monsoon onset is all set to move out of the region.(2/3)
May 30, 2025 at 9:13 AM
A series of westward propagating equatorial Rossby waves that were interacting with the developing background monsoonal circulation to enhance rainfall and accentuating monsoon onset is all set to move out of the region.(2/3)
Weakening La Nina background state and emerging warming in the eastern equatorial Pacific along with MJO would determine the global tropical rainfall pattern for the next 1-2 weeks.(4/4)
March 26, 2025 at 1:00 PM
Weakening La Nina background state and emerging warming in the eastern equatorial Pacific along with MJO would determine the global tropical rainfall pattern for the next 1-2 weeks.(4/4)
Meanwhile, SST anomalies over Nino regions are exhibiting a rising trend again in the past one week after decreasing for a short period prior to last week.(3/4)
March 26, 2025 at 1:00 PM
Meanwhile, SST anomalies over Nino regions are exhibiting a rising trend again in the past one week after decreasing for a short period prior to last week.(3/4)
This would enhance the Australian Monsoon Trough/poleward propagation of organized convection with an uptick of synoptic scale Lows/Cyclones over the northern coast of Australia. NWP based global models are quite uncertain about the future evolution of MJO in terms of its strength/propagation.(2/4)
March 26, 2025 at 1:00 PM
This would enhance the Australian Monsoon Trough/poleward propagation of organized convection with an uptick of synoptic scale Lows/Cyclones over the northern coast of Australia. NWP based global models are quite uncertain about the future evolution of MJO in terms of its strength/propagation.(2/4)