Monsoon Watch - 3
1.-As a result of the W.D.,the day temperatures in the northern regions of the sub continent have been below normal throughout the first 10 days of April. In fact the rainfall across the border in Pakistan was heavy with many places geting rain amounts in excess of 50mm/day last week.
Another weak W.D. is scheduled to cross the regions of north Pakistan through to India on the 12th. April. It will cover the states of Kashmir, H.P., Uttaranchal and may not be very heavy in precipitating rains. However, the days will start to get hotter in the Sindh areas of Pakistan and the Gujarat,Maharashtra and plains of northern India in the next few days. But, I do not see a real "heat wave " coming in the next week. So, the formation of the seasonal low over north India/Pakistan region may well start to form after the 15th. At present the w.d.s are preventing the proper low from forming.
2-In the southern peninsula, the line of wind discontinuity is a bit disorganised. This needs to get organised again, and form into a trough (atleast by the 20th.), and subsequently, this trough remains till the onset of the monsoon, when it becomes horizontally east-west, and merges with the monsoon trough. Also, the wind discontinuity line needs to be proper by mid April, to bring "oft and on" thundershowers in the southern states to increase the moisture in the atmosphere.
3-In the bay, as the map shows, the sst are a bit below normal, in the southern seas. Needs to come to at least normal levels to form the pre monsoon low. I expect the temperatures to reach normal levels by the20th. And no major international model shows the formation of a low in the bay till the 20th.
All the 3 parameters above can get organised into proper formation by the 20th., which is the normal date for the sequence of events, and if maitained, may not delay the monsoon.
Another important factor,the monsoon thrust from below the equator too, needs to give proper support to the buid-up around the sub-continent. But the various parameters of the southern hemisphere need to be followed later, after the 15th. of April.