New Delhi, Monday September 06, The monsoon trough that is essentially a convergence zone of opposing wind patterns is observing a peculiar shape of a rightwards tilted Y in the last few days. Usually a line running west to east from northwest India to Bay of Bengal, the monsoon trough branches out near Bihar as another flank albeit weaker runs straight to Northeast India. The northeastern arm though faint is interacting with continuing moisture incursion from the Bay of Bengal and will keep the region under rain for some time to come. Widespread moderate showers are expected over Arunachal Pradesh, Assam, Meghalaya, Nagaland, Manipur, Mizoram, Tripura, Sub-Himalayan West Bengal and Sikkim. Arunachal, Assam, Meghalaya, Sub-Himalayan West Bengal and Sikkim can get some heavy isolated showers as well.

The western part of the trough is anchored to a cyclonic circulation over east Rajasthan. The cyclonic circulation is likely to move a little east towards west Uttar Pradesh that may pull the trough upwards nearer to Delhi. The monsoon trough today passes through Anupgarh, Alwar, Gwalior, Rewa, Ambikapur, and the centre of a low pressure area off Orissa coast before dipping in to east central Bay of Bengal.

Extensive rain is likely over all of Northwest India including east Rajasthan, Punjab, Haryana, west Uttar Pradesh, Uttarakhand and Himachal Pradesh. The rainfall will however be more intense in Uttarakhand, east Rajasthan and west Uttar Pradesh with moderate showers. East Rajasthan may also get a few heavy drenchers. Delhi might be witness to some passionate rains during early morning and evening hours as the monsoon trough heaves near the city. West Madhya Pradesh will also receive some light rainfall as a trickle down effect of the monsoonal activity in the region.

On the eastern front, a fresh low pressure is evolving off the Orissa coast. But like many others developing in the Bay of Bengal region, this will also make landfall and progress further inland in the same nondescript manner. Orissa, especially its southern parts will be under good amounts of rainfall today onwards as the weather system moves in through this part of the coast. The adjoining parts of Chhattisgarh and east Madhya Pradesh will be the next stops for the invading low pressure, ushering in moderate showers here in the next 24 to 48 hours here as well. Gangetic West Bengal, Bihar and Jharkhand will get a few light seasonal monsoon showers.

There is a trough prevailing along the West coast as well. This north-south trough off the West coast is a seasonal feature during monsoons and its strength decides the vigour of rainfall in the region. The trough although runs from coastal Gujarat to Kerala but remains feeble in absence of any new moisture impetus from the Indian Ocean. But local moisture will beget moderate rain over Gujarat, Konkan and Goa during the next day. Mumbai will be under moderate showers albeit of lesser fervour. The areas to the south of Goa will get showers bordering mild.

Interior Karnataka, Marathwada and Madhya Maharashtra may receive some light rainfall as the coastal moisture blows inland gradually. North coastal Andhra Pradesh may also get a few showers from the clouding associated with the low pressure off the Orissa coast in the next 24 hours.