Why Karnataka continues to undergo wet spell

India Meteorological Department (IMD) said that parts of Karnataka, including Bengaluru, continued to receive rainfall due to the presence of a cyclonic circulation in the region. The weather department explained that there was a cyclonic circulation over the southwest Bay of Bengal off southern Andhra Pradesh, which coupled with a trough, was drawing moist winds to the state, causing rain. A cyclonic circulation is a large-scale circulation of winds around a central region of low atmospheric pressure, which is counter-clock wise in the northern hemisphere.

Moreover, a trough is essentially a turning of the winds that accumulates moisture. Moreover, there is another cyclonic circulation over the Gulf of Mannar. It is to be noted that the South West Monsoon (SWM), which brings Karnataka most of its rainfall, withdrew from the state on October 15. However, on the same date, IMD declared that there was an onset of the North East Monsoon (NEM). The states that are mostly affected by the NEM are Tamil Nadu and Kerala. However, it also brings some rain to parts of Old Mysuru and Andhra Pradesh. The presence of weather systems is drawing rain-bearing clouds to the state as well.

Not Dana effect: IMD; IMD scientist Puviarasan clarified that the cyclone Dana in the Bay of Bengal, which made landfall on the Odisha coast on October 25 had no bearing of rain in Karnataka because it was far away from the state. Bengaluru had received heavy rain in the third week of October. “It is a circulation. We call it a cyclonic circulation because it moves in the anti-clock wise direction. It is different from a cyclone. Cyclone means its wind speed is more than 34 knots (1 nautical mile or 1.15 mile or 1.85 kilometers) per hour.

Circulation means we can’t see anything in the charge. That is to say we can see it only in the upper air. So this circulation is giving rainfall,” he said. “Whenever a circulation forms over the neighbouring area or southern Bay of Bengal, then it moves winds from east to west, then Karnataka also gets rainfall,” he added. The IMD scientist said that showers were expected in parts of Karnataka in the days to come.