After a hiatus, rainy days are back in Kerala

IMD issues yellow and orange alert for various districts for next five days indicating heavy to very heavy rains

After a gap, cloudy skies with intermittent showers and a few intense spells of rain are likely in Kerala in the coming days fuelled by a low pressure area over the Arabian Sea. A zone of positive cyclonic vorticity is seen over the west equatorial Indian Ocean and adjoining parts of the southeast Arabian Sea. Most of the global weather models are indicating the development of a low pressure area over the southeast Arabian Sea around October 11.

While, some of the models, including India Meteorological Department Global Forecast System (IMD GFS), National Center for Medium-Range Weather Forecasting Unified Model (NCUM), and National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) (NCEP GFS) are indicating intensification of the system into a depression around 13 October over the east central Arabian Sea.

Though these models are also indicating further intensification of the system, the European Centre for Medium-Range Weather Forecasts (ECMWF) and Global Ensemble Forecast System (GEFS) are not supporting any significant intensification. However, the system is likely to trigger heavy to very heavy rains at least a few stations in Kerala during the next few days, like in the pattern of monsoon rains. During the northeast monsoon period, heavy thunder showers accompanied by gusty wind used to lash Kerala, especially in the afternoons.

The prevailing westerlies are likely to have a bearing on the onset of northeast monsoon, although the reversal of wind from westerlies to easterlies is the main attraction of northeast monsoon. According to the IMD, the southwest monsoon should be withdrawn upto the latitude of coastal Andhra Pradesh (15 degree latitude) and deep easterlies (up to 850 hPa) should have set in over Tamil Nadu or seasonal low should have established in the South Bay of Bengal adjacent to the Tamil Nadu coast. If these conditions are satisfied with widespread rain over coastal Tamil Nadu, the onset of northeast monsoon will be declared.

The long period average onset of northeast monsoon for the period 1901-2021 is on October 19 with a standard deviation of plus or minus 8 days. An onset of Thulavarsham from October 11 to 27 can be considered a normal onset date during the post-southeast monsoon. The India Meteorological Department (IMD) has issued a yellow and an orange alert for various districts for the next five days indicating heavy to very heavy rains.

Thiruvananthapuram, Idukki, Palakkad, Malappuram, Kozhikode, and Wayanad districts were put on yellow alert on Monday by the IMD warning of isolated heavy rains, while an orange alert is issued for Idukki on Tuesday, Kottayam, Ernakulam, Idukki, and Thrissur on Wednesday and Thiruvananthapuram, Kollam, Pathanamthitta, and Kottayam on Thursday, warning of heavy to very heavy rains, according to an IMD bulletin on Sunday.

Published - October 06, 2024 08:31 pm IST