Bay Region: Carrying on from the Monsoon Watch-12, the waters of the bay have since started heating up as is seen here. The formation of a low now seems probable by the 14th. But it seems the low may not be very strong as it is likeley to form in the east central bay, around the islands of north Andamans, around the 15N region.The ECMWF also forecasts the formation of a low in the north Andaman region by the 16th., and the system may get a bit stronger before crashing into the north Mynamar/Bangaldesh coast by the 19th. As a result, the south west monsoon, already declared in the south Andamans by the IMD, will be pulled upto the north Bay by that date. Cross equatorial winds are not strong enough yet today to pull the monsoon beyond the declared limit for another 2/3 days.
Most of the strenght of the bay current is going to get pulled away by the likely formation of a tropical storm on the south china sea during the 15th.-19th. period.
Sub continent Mainland : The day temperatures are still below normal for a larger part of the sub continent. The areas under the "below normal" regions are covering most of the regions required to be under heat waves as on date. But the east coast has heated up, and Gannavaram and Vijaywada there were 45.8c (+6) on the 11th. Across in Pakistan, Nawabshah was 47c on the 11th. as the highest in the region. The seasonal low in the northern areas is still premature, and the low formation is distorted at 1000mb.
Arabian Sea: The high pressure at MSL is now prominent in the sea. In a way, this can linger on for another week without really causing any damage or diversion to the monsoon winds. In fact, this'' high'' should get the somali current winds moving fast, and strenghten them. I see the somali winds just about forming as on the 11th. Should be in full strenght by the 19th.
The jet streams, at 200hpa. over the Indian sub continent have just started their northward shift in the last couple of days. In the monsoon season. the jet streams, sometimes at 100 knots, should ideally be east-west, with the centre core at around 15N. Today they are west-east above 22N, while on the southern tip of the peninsula, the 200hpa streamline (map) shows a weak east-west formation starting.
Ideally, the monsoon should now cover the bay area by the 20th.Monsoon winds in the North-eastern states, and the arabian Sea segmant will gain strenght and progress after the 25th.of May.