Southwest monsoon to hit Kerala on June 9: IMD

PUNE: All other criteria being already met, with the expected enhancement in cloudiness over Lakshdweep, the India Meteorological Department (IMD) says that the onset of the south west monsoon is going to take place by June 9.

"In view of strengthening of cross equatorial flow and deepening of westerlies over south Arabian sea and development of feeble off­shore trough along Karnataka­Kerala coast, onset of monsoon over Kerala is very likely by June 9," stated an IMD forecast.

Among the stringent criteria set by the IMD in 2006 for the declaration of onset of monsoon over Kerala, the important one's are related to rainfall, wind speed and the outgoing radiation.

Onset of monsoon is declared if 60 per cent or more of the 14 weather stations spread along the coast of Kerala, some part of coastal Karnataka and Lakshdweep, get more than 2.5 millimeter rainfall for two consecutive days, provided following criteria is also met.

"While rainfall condition has already been met, the second criteria is related to the speed strength and depth the westerly winds should attain. This criteria has started turning positive for the onset of the monsoon," said Sunitha Devi, director (weather section), IMD, Pune.

The third criteria is about the cloudiness around a particular region near Lakshdweep islands. Specifically, the area between latitude 5 degree to 10 degree (North) and longitude 70 degree to 75 degree (East). More the cloudiness, lesser the outgoing longwave radiation (OLR) from the Earth. The criteria says that the cloudiness should be so much that the outgoing radiation should be less than 200 Watts per meter square. The IMD expects meet this criteria by June 9.