Monsoon Covers India Early This Year

Summary of the Southwest Monsoon Progress and Performance in June 2023

The southwest monsoon achieved complete national coverage in India on June 29, 2023, nine days earlier than the expected date of July 8, marking only the tenth time since 1960 that such early coverage occurred. The monsoon onset in Kerala took place on May 24, 2023, which was eight days ahead of the usual onset date of June 1.

Factors Contributing to Rapid Monsoon Progress:

1. Active Madden-Julian Oscillation (MJO):

   • The MJO is a climatic phenomenon characterized by patterns in wind, cloud, and pressure. Its active phase in mid-May and June enhanced cloud formation over southern India, promoting early monsoon winds and rainfall.

2. Development of Low-Pressure Systems:

   • Five low-pressure systems formed in India throughout June. These systems attract moisture-laden winds, facilitating rainfall and propelling the monsoon inland.

3. Monsoon Trough Position:

   • The monsoon trough’s position remained mostly to the south of its average location in June, allowing for increased moisture influx, thereby accelerating the monsoon’s arrival across the nation.

4. Neutral Phase of ENSO and IOD:

   • The El Niño-Southern Oscillation (ENSO), in its neutral phase, and the Indian Ocean Dipole (IOD), also in a neutral phase, contributed to favorable conditions for monsoon progression. While El Niño can suppress rainfall, neutral phases typically support normal rainfall patterns.

Rainfall Performance in June 2023:

• The all-India average rainfall for June was recorded at 180 mm, which is 9% above the normal average. This marks a positive deviation, ending a streak of deficit rainfall trends that started in 2022.

• Central India’s rainfall was notably high, with an average of 212.6 mm, a 24.8% increase from the norm, the first such trend observed since 2022.

• However, east and northeast India continued to experience below-normal rainfall for the third consecutive year, showing a 16.9% deficiency with 272.9 mm recorded.

• State-wise Impacts:

  • For the first time since 2019 and 2020, Manipur (242.7 mm) and Mizoram (466.9 mm) achieved normal rainfall levels.
  • The month concluded with below-normal rainfall recorded in several regions, including Arunachal Pradesh, Assam, Meghalaya, Sikkim, Bihar, Delhi, Chhattisgarh, Andhra Pradesh, Telangana, and Lakshadweep.

• About 80% of meteorological subdivisions reported normal or above-normal rainfall in June, crucial for kharif sowing activities across the agricultural sector.

Key Points:

• Complete monsoon coverage achieved on June 29, 2023.
• Early onset in Kerala on May 24, 2023.
• MJO and low-pressure systems significantly aided monsoon advancement.
• Overall June rainfall 9% above normal; Central India reported a 24.8% increase.
• Notable rainfall deficiencies persist in east and northeast India.
• State-wise rainfall recovery reported in Manipur and Mizoram.
• Most subdivisions received satisfactory rainfall, essential for the kharif crop season.

This summary encapsulates the critical aspects and impacts of the southwest monsoon in June 2023, detailing the climatic factors, performance, and regional implications, relevant for understanding agricultural and water resource management in India.