The Indian Meteorological Department (IMD) forecasts a near normal Southwest Monsoon for 2019 suggesting that June to September rainfall is likely to be 96 percent of the Long Period Average (LPA). The onset date of the Southwest Monsoon is forecast for June 6, which is a delay of five days. Central India has been receiving normal to excess rainfall during the pre-monsoon period, while most of the other regions have received deficit rainfall from the previous year. These trends are reflected in their corresponding reservoir storage levels.
IMD predicts near normal monsoon
On April 15, the Indian Meteorological Department (IMD) forecast a near normal Southwest Monsoon for 2019 suggesting that June to September rainfall would likely be 96 percent of the long period average (LPA) with a model error of plus/minus 5 percent. The fifty-year (1951-2000) LPA for the Southwest Monsoon rainfall is 89 cm. The forecast suggests a maximum probability (39 percent) for normal rainfall during the upcoming season. However, there is less probability for the monsoon rainfall to be above normal or excess. Overall, the country is expected to have well-distributed rainfall during the monsoon season. However, Indian private weather forecasting agencies are forecasting a below normal monsoon. IMD’s second forecast is scheduled for release in the first week of June. For more details, please refer to IMD Press Release - Long Range Forecast of 2019 Southwest Monsoon.
Southwest Monsoon onset on June 6, 2019
On May 15, IMD issued a press release stating that Southwest Monsoon onset is likely to start over Kerala on June 6 with a model error of plus/minus 4 days. Typically, the start of the Southwest Monsoon is marked by an onset over the southern state of Kerala on June 1 with a standard deviation of about 7 days. After that, it takes approximately 45 days to cover the entire country. The event marks the start of the rainy season over the region and as the monsoon progresses northward, relief from high summer temperatures is experienced over the areas.