A few/isolated places over Tamil Nadu, Puducherry, Karaikal and Kerala received showers on Monday while isolated places over Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Punjab, Haryana, Chandigarh and Uttar Pradesh witnessed snow/rain as a slow-moving western disturbance reached East Afghanistan but continued to extend its influence over regional weather.
Stations recording the highest amount of rainfall (three cm each) on Monday are Ayikudi, Thalaignayer, Tirupoondi and Velankanni; and two cm each at Adirampattinam, Kodiakarai, Coonoor, Rameswaram and Sattur-2, all in the Tamil Nadu-Karaikal-Puducherry meteorological subdivision. Clouds extended into Peninsular South from East India on Tuesday evening.
Offspring cyclonic circulation
An India Meteorological Department (IMD) update said Bareilly, Aligarh and Shahjahanpur in West Uttar Pradesh recorded one cm of rain each. The wet weather is attributed to a cyclonic circulation over South-West Rajasthan that the incoming ‘active’ disturbance gave birth to. Active disturbances are known to spawn such circulations ahead of its arrival over North-West India.
The western disturbance combined with the circulation had dug deep into the Arabian Sea setting of moisture-laden south-westerly winds along the Kerala coast, Kanyakumari and adjoining tip of the South Peninsula as also South-East Tamil Nadu and Sri Lanka to immediate South-East. Satellite pictures on Tuesday evening showed thunderclouds persisting over these regions.
Stormy conditions likely
Thunderclouds lined up over the Central Indian Ocean (South of Sri Lanka) and grew in prominence to East over South-West Bay of Bengal and adjoining South Bay. Early numerical model predictions suggest formation of a weather system (low-pressure area/depression). Some models did not rule out a track toward the North Tamil Nadu-South Andhra Pradesh coast.
This is expected to happen towards the the weekend, according to these predictions. The IMD has hinted squally weather may develop over the South-West Bay off Sri Lanka and Tamil Nadu coasts simultaneouslsy. Winds reaching 40-45 kmph in speed gusting to 55 kmph are forecast from Friday (January 27). Fishermen have been advised not to venture out to these areas.
Follow-up western disturbance
The IMD has hinted a second western disturbance, likely of the same intensity as its predecessor, may hit North-West India around this time. These back-to-back disturbances with their deep anchor are expected to interact with an equally slow-moving but strong pulse of the weather-friendly Madden-Julian Oscillation (MJO) wave parked currently over the Central Indian Ocean.
The US National Centres for Environmental Prediction says that the second western disturbance will suitably influence the ongoing weather pattern over the South Peninsula where the wet spell may last into the first week of February (especially over South and Central Tamil Nadu and adjoining Kerala), right into the midst of a prevailing hot and dry weather over the region..