The second factor is weak Madden-Julian Oscillation activity. The MJO is an eastward-moving pulse of clouds, rain and storms that travels around the tropics every 30-60 days. When it is active over the Indian Ocean, it can help strengthen convection over the Arabian Sea and the Bay of Bengal, aiding monsoon rainfall.
“Madden-Julian Oscillation remains weak and away from the Indian Ocean. There is a possible influence from developing strong El Niño conditions,” Vagaries of Weather said.
The third factor is dry air intrusion from the north and north-west. “Strong western disturbances recently moved across North India. Dry continental air from north/north-west India has spread southward,” the weather blog said. This has limited cloud formation and monsoon convection.
The fourth factor is the weak development of the Somali Jet, a low-level wind current that helps drive the southwest monsoon towards India. The monsoon has also lacked support from low-pressure systems in the Bay of Bengal, which often help pull the monsoon inland. Usually the typhoons in the Pacific Ocean also send remnants of low pressure areas which intensify in the Bay of Bengal which has also not occurred in June 2026.
The fifth factor is the neutral Indian Ocean Dipole. A positive IOD, when the western Indian Ocean is warmer than the eastern side, can support monsoon rainfall. The IOD is currently neutral and is expected to remain so, according to the latest India Meteorological Department forecast.
Raghu Murtugudde, emeritus professor at the University of Maryland and visiting professor at the Indian Institute of Technology, Kanpur, said the issue was not simply a lack of moisture. “Winds are blowing and reaching up to a couple of kilometres as expected. They are bringing in the moisture but atmospheric subsidence is inhibiting convection,” he said.
He said the pattern appeared to be linked to conditions over the Bay of Bengal, where cross-equatorial winds were not curving back into the core monsoon zone as expected. “That’s why the eastern end of the trough is bent over like the handle of an umbrella and producing only spotty rain over the east-northeast,” he said.
“This allows the drier air to intrude into the northwest and fire up thundershowers. The core zone is not getting the convergence of the jet from the Arabian Sea and the return flow from the Bay,” he added.