A depression over the southeast Arabian Sea, south of Porbandar in Gujarat, is likely to move northwestward and intensify into a cyclonic storm Biparjoy may impact the onset of the southwest monsoon in Kerala. With the monsoon already missing its onset date over the Kerala , the India Meteorological Department (IMD) will keep a close watch on the development of a cyclone over the Arabian Sea over the next few days.
In the last week of May, IMD had forecast June 4 as the probable onset date of monsoon over the Kerala coast. As of June 5, the northern limit of the monsoon is yet to move from Sri Lanka and touch the Kerala coast. IMD officials say the monsoon is now expected to touch the Kerala coast in the next three to four days. In a bulletin, the Met office said the depression lay about 950 km west-southwest of Goa, 1,100 km south-southwest of Mumbai, 1,190 km south of Porbandar and 1,490 km south of Karachi, Pakistan, at 8:30 am. "It is likely to move nearly northwards and intensify into a cyclonic storm during over east-central Arabian Sea and adjoining southeast Arabian Sea," it said.
All ports in Gujarat have been asked to hoist a warning signal as a depression formed in the Arabian Sea is likely to intensify into a cyclonic storm during the next 24 hours, the IMD said. The Met office said the cyclonic storm will intensify into a severe cyclonic storm by Thursday morning and very severe cyclonic storm by Friday evening. Sea conditions are likely to be very high along and off the Kerala-Karnataka coasts and Lakshadweep-Maldives areas on June 6 and Konkan-Goa-Maharashtra coasts from June 8 to June 10. Fishermen out at sea have been advised to return to the coast.
Private forecasting agency Skymet Weather said the monsoon onset over Kerala may happen on June 8 or June 9 but it is expected to be a "meek and mild entry". "These powerful weather systems in the Arabian Sea spoil the advancement of the monsoon deep inland.
Under their influence, the monsoon stream may reach coastal parts but will struggle to penetrate beyond the Western Ghats," it said. Skymet had earlier predicted the monsoon onset over Kerala on June 7 with an error margin of three days. "The southwest monsoon is likely to arrive within this bracket. Onset criteria require stipulated rainfall on two consecutive days over Lakshadweep, Kerala and coastal Karnataka. Accordingly, the spread and intensity of rainfall may match these requirements on June 8 or June 9.
However, the onset of the annual event may not be loud and sound. It may only make a meek and mild entry to start with," the private weather forecasting agency said. D S Pai, senior scientist, IMD, said Kerala received good rain on Monday too and conditions are favourable for the onset of monsoon over the next two to three days. Southern peninsula will get rain under the influence of the cyclonic storm and a low-pressure system developing in the Bay of Bengal. However, further progress of the monsoon beyond the southern peninsula will happen after the cyclone degenerates, Pai said.
The southwest monsoon normally sets in over Kerala on June 1 with a standard deviation of about seven days. In mid-May, the India Meteorological Department (IMD) said monsoon might arrive in Kerala by June 4.