Above-normal rain expected in August and September, says IMD

Sub: Geo

Sec: Climatology

Context:

The India Meteorological Department (IMD) predicts above-normal rain for August and September.

Monsoon Rainfall Prediction:

August is expected to receive normal rainfall.
September is likely to receive more than the average 17 cm of rainfall if the forecast of an “above-normal second half” of the monsoon holds true.
The IMD predicts rainfall from August to September to be above normal, exceeding 106% of the Long Period Average (LPA).

El Nino and La-Nina conditions:

El Nino and La Nina are complex weather patterns resulting from variations in ocean temperatures in the Equatorial Pacific Region. They are opposite phases of what is known as the El Nino-Southern Oscillation (ENSO) cycle.
- The ENSO cycle describes the fluctuations in temperature between the ocean and atmosphere in the east-central Equatorial Pacific.
El Nino and La Nina episodes typically last nine to 12 months, but some prolonged events may last for years.
El Nino is a climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean.
- It is the “warm phase” of a larger phenomenon called the El Nino-Southern Oscillation (ENSO).
- It occurs more frequently than La Nina.
La Nina, the “cool phase” of ENSO, is a pattern that describes the unusual cooling of the tropical eastern Pacific.
- La Nina events may last between one and three years, unlike El Nino, which usually lasts no more than a year.
Both phenomena tend to peak during the Northern Hemisphere winter.

Impacts of Increased Rainfall:

Increasing rainfall in September could damage standing crops.
La Nina or La-Nina-like conditions may develop by the end of August, potentially leading to more rain in September.
Heavy rain in September and October, when the monsoon retreats, can affect winter sowing and increase air pollution in northern India.

Source: TH