A city bracing for traffic-stopper Mamata Banerjee on Thursday was, instead, thrown out of gear by the rain and the waterlogging. And there?s no immediate respite in sight, warns the weatherman.

As the low pressure over the Bay of Bengal inched towards the Bengal delta ? it now lies about 1,000 km from Calcutta ?incessant showers hit the city for the second successive day.

A wet Wednesday night was followed by drizzle, downpour and disruption under overcast skies ? the Alipore weather office recorded 70 mm of rain, while at Dum Dum, 90 mm was recorded till 8.30 am on Thursday.

?The situation is unlikely to improve much during the next 48 hours,? warned G.C. Debnath, director of the weather section of the regional meteorological centre at Alipore.

He said the sky over Calcutta and its neighbourhood ? which had seven to eight-km-tall cloud columns on Thursday morning ? would remain cloudy, with intermittent rain.

?One or two spells may be heavy to very heavy,? he added in warning.

According to Debnath, the low pressure that lay over south-west and west-central Bay of Bengal, off the Tamil Nadu and Andhra Pradesh coasts, had moved up and now lay over the west-central Bay, off the adjoining Andhra Pradesh and south Orissa coasts.

The low pressure hovers about five km above sea level.

?Under its influence, there will be rain in almost all places of Gangetic Bengal and many places in the districts of sub-Himalayan Bengal. Heavy to very heavy rainfall is likely to occur at a few places in the districts of Gangetic Bengal. Also, heavy rainfall is likely at isolated places over the north Bengal districts,? explained Debnath.

Met officials were glued to the radar screen throughout Thursday, watching the low pressure inch towards Bengal.

?We are keeping a close watch to see whether it hits the land. The system is strong enough to spell trouble and so far, it has not shown any signs of weakening,? said an official.

The wind speed on Thursday, however, was not as gusty as on Wednesday.

Met officials explained that once the system hits the land, it will weaken and gradually dissipate.

?As long as it is over the sea, it will continue to pick up moisture and could intensify into a depression,? they said.

Formation of any low pressure in the Bay of Bengal at this time of the year is a matter of concern for the Met office.

?From October, the cyclone season begins. Around this time, we have frequent formation of low-pressure zones and depression in the Bay of Bengal. Some low pressures intensify into depressions and rush towards Bengal or Orissa or veer towards Bangladesh,? said an official.