Tuesday, August 2: It has been a normal (yet erratic in most parts) first half of the 2022 southwest monsoon season. While the country’s overall rainfall figures between June 1 and August 1 stand at 487 mm — slightly higher than normal — states like Uttar Pradesh and Jharkhand have witnessed a nearly 50% deficit, while the likes of Telangana and Tamil Nadu have seen double the normal rainfall in the first two months.
Now, we have arrived at the halfway point and are staring at a somewhat similar second half. And keeping its custom alive, the India Meteorological Department (IMD) has released the long-range forecast outlook for the final two monsoon months, thereby shedding light on what’s expected through August and September.
A ‘normal’ second half on horizon
The long-range forecast has indicated that the collective monsoon rainfall across the country through August and September is likely to be normal — [94-106% of India’s long-period average (LPA) for the second half]. This LPA, based on the rainfall data accumulated from 1971-2020, stands at 422.8 mm.
Regionally, the discrepancies are likely to prevail in the second half as well. The precipitation will be normal to above normal over parts of southern, west-central and northwest India but below normal in many parts of the western coast and some parts of east-central, eastern and northeastern India.
As for August alone, the countrywide rainfall will remain normal, amounting to 94-106% of the month’s LPA of 254.9 mm. Southeast, Northwest and West-Central India will be in for a wetter-than-usual August, but drier conditions may be observed across the northeastern, eastern, east-central and western coastal states.
Warmer days and nights in store for many parts
With regards to the mercury levels, the daytime temperatures are expected to be above-normal for many locations across east-central, east and northeast India and some parts of northwest and south interior peninsular India. The remaining regions will witness normal to below-normal warmth during the days.
On the other hand, the minimum temperatures will remain above normal in some parts of east-central, east, northeast and the hilly areas of northwest India, but below normal across many parts of northwest, west-central and south India.
Sea-surface temperatures’ impact on second-half rainfall
The IMD’s long-range forecast has also revealed that at present, the La Niña conditions that currently persist over the equatorial Pacific region are likely to continue until the end of the year. The prevalence of such conditions normally aids the monsoon rainfall activity across India.
But on the flip side, neutral Indian Ocean Dipole (IOD) conditions with a negative Dipole Mode Index (DMI) are also present over the Indian Ocean, with the latest MMCFS forecast predicting the possible development of negative IOD conditions during the second half. This could result in a negative, weakening impact on the Indian monsoon.
The story so far
In spite of multiple flooding episodes across the country and several rainfall records being broken, the overall precipitation across India during the opening months of June and July remained ‘normal’, just 7% higher than its two-month average of 454.7 mm.
In the same period, the rainfall registered by each region has been as follows:
- East and Northeast India – 652.9 mm (14% lower than 763.1 mm LPA)
- Central India – 579.2 mm (15% higher than 502.6 mm LPA)
- South Peninsular India – 476.4 mm (28% higher than 372.3 mm LPA)
- Northwest India – 308.5 mm (4% higher than 295.2 mm LPA)
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