Funding information Ministry of Earth SciencesGround-based cloud radar has been used for the first time in the Indian subcontinent to explore the cloud population during the break, transition and active phases of monsoon intra-seasonal oscillation over a region in the Western Ghats mountain. The synergetic use of in situ measurements along with the supporting large-scale microphysical features from the reanalysis data has been utilized in order to have a closer look of the morphology of clouds along with its transition during the intra-seasonal phases. It has been observed that the active phase is dominated by deep clouds (~41%) along with some shallow (~28%) and congestus clouds (~29%) while the break phases are dominated by the shallow clouds (~72%) during precipitating and high-level cirrus clouds (~65.22%) during the non-precipitating times. The role of middle level moisture for modulating the nature of the clouds along with its role in determining the latent heating profile over the same region has also been presented.

The heat and momentum flux transfer by transient eddies from the extratropical to the tropical (E2T) region causes a significant variation of weather and climate in the tropical region. Such transports also cause a regional departure from zonally symmetric large scale circulation patterns caused by the Hadley type transports. During boreal summer monsoon season, the zonally symmetric Hadley type circulation is typically considered in theoretical as well as modelling studies. The current study introduces a method based on the calculation of the E-vector components and co-spectra analysis to diagnose the zonally asymmetric climatological patterns of E2T transport and its subseasonal variability. The spectral analysis identifies the climatological as well as low and high frequency patterns of the transient eddy heat and momentum flux transfer over the Indian region and compares the result with traditional Eliassen-Palm (EP) Flux based stationary eddy patterns. The study identifies the zonal, seasonal, and vertical asymmetries in the transport of transient eddy heat and momentum flux. The study also clearly categorizes the seasonality and frequency dependence of northeast to the southwest tilt of transient eddies transporting momentum and heat flux. Based on the climatological patterns, the wavelet transform approach is used to study the subseasonal variability of the eddy transport indices. We define a set of indices, which identify the subseasonal temporal variation of the E2T transfer mechanism. These indices could be used to operationally track the E2T eddy flux transfer both in observation and in forecast models.