The cloudy Calcutta skyline framed against the silhouette of freedom fighter and martyr Matangini Hazra’s statue on the Maidan on Tuesday afternoon. (Sanat Kr Sinha)

A Nor’wester struck on Tuesday afternoon but Calcutta barely felt it.

The skies darkened a little after 3pm, the first rumble of thunder was heard around 5pm and raindrops began to fall soon after, fuelling hope for that long overdue downpour. The breeze was brawny for no more than 20 minutes and the light rain that followed lasted half that period.

The Met office said the wind speed “wasn’t enough” but the forecast is for storms over the next few days. “The conditions are finally favourable for thunderstorms,” said Gokul Chandra Debnath, director of the Regional Meteorological Centre.

Satellite pictures show a cyclonic circulation over the Chota Nagpur Plateau in Jharkhand. There is also a high-pressure belt over the Bay to aid incursion of moisture from sea to land.

Inadequate incursion of moisture so far has been blamed for the absence of strong thunderstorms in the region.

Tuesday’s was one such. A.K. Sen, director of the Patna Met office, said that sometimes a Nor’wester passes through Jharkhand without any rainfall activity. “The dry north-westerly wind gains momentum and results in rain when it gets sufficient moisture. Sometimes it doesn’t get moisture in the Chhota Nagpur Plateau, due to which we are deprived of a Nor’wester. But the same wind moves forward and as and when it comes in contact with heavy moisture in the coastal region of Bengal, it results in rain,” Sen explained.

Usually, the first storm strikes Jharkhand and Bengal in the last week of March, when the maximum temperature hits 35 degrees Celsius and above. If conditions are favourable, Nor’westers continue to strike till the first week of June.

In 16 days of April, Calcutta has received 1.4mm of rain, which compares poorly with last year, when it had received 103.1mm of rain in the same period.

The average aggregate rainfall in Calcutta in April is 58.8mm, based on data from 1971 to 2000. April 2013 has a lot of catching up to do.