Plain Language Summary:
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After a weak onset and a sluggish start, the summer monsoon rainfall is now heading towards a significant hiatus over the Indian subcontinent during the next 10 days. Numerical Weather Prediction and AI based model guidance from various modeling centers across the globe indicate that the progress of monsoon rains over India could see a temporary halt as the monsoon circulation and rainfall pattern is all set to weaken and dry air advection could take a dominant role. Rainfall is expected to be subdued across the Western Ghats, the west coast, central and major parts of western and peninsular India. This could be a serious concern for the Agrarian community as several parts of India could see a delay in the sowing activities where irrigation is not available. Models although indicate some revival after the 20th of June, uncertainty prevails as of now on the date and pattern of revival. The situation needs continuous monitoring in the days to come with El Nino strengthening along side.
Scientific Diagnostic Reasoning:
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Analyses of the observed global tropical circulation pattern during the past 2 weeks suggests that the Indian summer monsoon rainfall onset phase found itself struggling against a backdrop of unfavorable sub seasonal and low frequency modes of tropical variability. RMM and 200 hPa Velocity Potential based MJO indices indicate that large scale eastward propagating wave saw itself working constructively with the evolving Low frequency ENSO state over the central and eastern Pacific during the past 2 weeks. The Monsoon circulation caught on to some westward propagating mode to help breath itself for a brief period to make some progress, but it could not stand against the other giant suppressing modes and eventually is giving up on further progression (temporarily). Extended range forecast charts indicate the presence of persistent lower level anticyclonic circulation and rainfall anomalies over India, and alongside dotted with some westward propagating equatorial waves in the lower latitudes. VP 200 hPa clearly indicates the strengthening El Nino conditions which could weaken the Walker circulation and hence the Monsoon in the background. The situation overall looks grim and needs continuous monitoring for management and mitigation on the agriculture and hydrological front.
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