In the first such reported incident of the season, dense fog disrupted surface and air traffic to some extent in Delhi and neighbourhood early this morning.
This came about even as a western disturbance kept waiting over north Pakistan to cross the international border and enter northwest India.
The lower pressure associated with the system is causing the moisture in front to rise and cool, throwing down the fog cover into the plains of northwest India.
US agency forecasts indicate that the westerly system will spin off a cyclonic circulation over Haryana, Punjab and adjoining east Rajasthan by tomorrow.
This will briefly push away from the region the resident anti-cyclonic circulation that has been presiding over chilly cold conditions over the past couple of days.
In this manner, the clouds could bring in some respite though the cold is likely to return from midweek.
Cold north-easterly to north-westerly winds could fan into the plains as the cyclonic circulation moves out along with the western disturbance.
Bay Storm Likely
Meanwhile, India Met Department has set up a watch for a low-pressure area/depression developing off the Sri Lankan coast by the weekend.
It suspects that the system may move north and run in towards Southeast Tamil Nadu coast into the Palk Strait eyeing the coast from Ramanathapuram to Nagapattinam.
The European Centre for Medium-Range Weather Forecasts too maintains this forecast but takes the system across the Bay of Bengal towards Kolkata.
In doing so, the system will careen along the Tamil Nadu coast setting off bringing to bear a surprisingly wet and stormy end to the year for the state.
Extended forecasts indicate that another system might take shape over the South China Sea bang in the New Year and set a track to enter the Bay of Bengal.