No cyclone, no low pressure; humidity to decide Karnataka rains, says IMD

Bengaluru, Apr 11: As expected, summer showers have begun bringing relief from the heat in several parts of the state. However, further rainfall will largely depend on an increase in atmospheric humidity. The India Meteorological Department (IMD) has clarified that there is currently no likelihood of a low-pressure system or cyclone formation.

According to the IMD, summer rainfall is possible only if humidity levels rise above 70% relative humidity (RH). At present, following recent showers, humidity levels have reached around 40% RH.

Typically, when humidity ranges between 40% and 70%, the chances of rainfall remain low. Only when this threshold is crossed can further summer showers be expected.

However, in Bengaluru, rainfall may occur once humidity crosses 50% RH. While coastal regions are considered plains, IMD officials treat Bengaluru on par with a hill station in terms of weather patterns.

In coastal districts, moderate to good rainfall accompanied by thunder and lightning has been observed in rural areas such as Sullia, Subrahmanya, Kadaba and surrounding regions, particularly during the evenings.

In contrast, urban areas have witnessed only occasional heavy showers, with intense heat prevailing for most of the time. Cloudy conditions coupled with strong sunlight have been prominent in cities, whereas rural regions have experienced more pleasant weather due to a mix of rain and sunshine.

Over the past four to five days, several parts of Dakshina Kannada and Udupi districts have experienced sudden cool conditions during early mornings.

With a gradual rise in humidity, moisture has been observed on plants and grass during morning hours, with humidity levels already touching around 35% RH. However, as the day progresses, heat intensity increases again, according to senior IMD scientists.

Temperatures are expected to rise again in the coming days. While regions that received rainfall are currently recording temperatures between 30°C and 34°C, it may increase to 38°C to 40°C. As temperatures rise, humidity levels are also likely to increase, creating favourable conditions for summer showers. Interior and southern parts of the state may see a rise of 2°C to 3°C, said an IMD senior scientist.

Another weather expert stated that moderate summer rainfall is likely to continue over the next four to five days across coastal, Malnad, and several parts of the state. If no low-pressure system or cyclone develops over the Indian Ocean, the southwest monsoon may arrive earlier than expected this year.