While parts of India received torrential rainfall during June due to the monsoon, El Niño will reassert itself, causing the monsoon to weaken, over the upper part of the Indian Ocean and Southeast Asia.
During a typical monsoon season, heat builds ahead of the phenomenon, then rounds of showers, thunderstorms and tropical systems bring torrential rainfall and cool India and many surrounding areas of Southeastern Asia.
El Niño is a warm phase of the fluctuation of sea surface temperatures in the tropical Pacific Ocean that tends to bring an above-average number of typhoons in the Pacific Ocean. A natural balance tends to reduce tropical activity and hence reduce rainfall over the upper part of the Indian Ocean.
A challenging to predict and less-known phenomenon, known as the Madden-Julian Oscillation (MJO) caused the monsoon to strengthen temporarily. This oscillation is a pulse of showers and thunderstorms that tends to migrate from west to east around the equatorial regions of the globe.
According to AccuWeather Senior Meteorologist Jason Nicholls, "During June, the MJO pulse shifted to the eastern part of the Indian Ocean area and lingered."
"Rainfall was 16 percent above normal for India as a whole during June thanks to the interaction with El Niño and the MJO pulse," AccuWeather Meteorologist Eric Leister said.
The size of the drought area will be smaller, compared to earlier analysis. Heavy rain in some areas during June will lessen the impact of lower rainfall amounts moving forward.
Assuming the pulse does not revisit the region until the autumn, El Niño and below-average water temperatures from Somalia to the Arabian Sea will slow the arrival of the monsoon or reduce its impact from western India through much of Pakistan during July and August.
Part of this area is responsible for a significant amount of grain crops and agriculture in general. Many days of dangerous heat are likely in this swath.
"While most of the Asia summer forecast remains unchanged including the onslaught of typhoons, we do expect a little more rainfall than previously thought from central India, including the Madhya Pradesh, to Odisha, India," Nicholls said.
In this area, a few more storms are likely to occur.
The weakening monsoon from the effects of El Niño will cause rounds of heavy rainfall to diminish from Bhutan and southern Tibet to the northern parts of Laos and Vietnam, as well as south-central China.
Farther south in Indochina, current dry conditions will trend toward typical rains as the summer progresses. However in southern Thailand, Malaysia, Singapore and Indonesia will trend drier with drought building or worsening.
"Even if another pulse was to develop in the region late in the summer or during the fall, it may be too late to turn the drought around in Pakistan and northwestern India," Nicholls said.
A weaker monsoon can have significant impact on temperatures in the region.
The stronger the monsoon, the more the air is rising and cooling in its vicinity. Immediately outside of the strong monsoon, air is sinking and substantially heating up.
"With a weaker monsoon, the areas within will tend to be warm, while areas nearby outside of it will still be hotter than average due to the building drought, just perhaps not as extreme," Nichols said.
There will be a flow of humid air over much of the region, leading to very spotty storms, but also resulting in very high AccuWeather RealFeel® Temperatures, reaching 100 F or higher most days.
The strong monsoon that occurred during June, helped to create the extreme heat in June over Pakistan and in parts of India.