Southwest Monsoon is a four month long season over the Indian region spanning from June to September, with a Long Period Average (LPA) of 89 cm of rain for this period.Monsoon in India could be conceived as a complex phenomenon, inherited with a variety of phases ranging from active Monsoon to weak, lull, break and the like. Monsoon experiences a lot of variation and not uniform throughout the season.
Southern parts of the country enjoy the complete four month duration of Monsoon, whereas North India actively observes only about two months of rainy season, before it recedes in September. June is the onset month which witnesses an outburst of rain while, September is the withdrawal month, receiving only sporadic rain. July and August are generally the active Monsoon months for the entire country.
In last few days, the Monsoon current remained weak for major part of the country and rain was confined to only few pockets. The national capital witnessed the last spell of rain on the 10th of August while Amritsar received just 9 mm of rain in last 10 days. Patiala did not receive any rain during this period.
Going by the present scenario, Skymet Meteorology Division in India confirms that Monsoon has gone into a break and the situation is likely to continue for at least another week. In Meteorological terminology, 'break' in the Monsoon comes when three or more consecutive days of rains are way below normal in the 'core Monsoon zone'.
During the Monsoon season, there are periods when the Monsoon trough shifts to the foothills of Himalayas, which leads to sharp decrease in rainfall over most parts of the country but increase along the Himalayas and parts of Northeast India and Southern Peninsula. Likewise, Dehradun received two spells of torrential rain of 120 mm and 135 mm, on the 15th and 16th respectively.
Mid of August is most prone to ‘breaks’ and that too longer breaks.
Skymet brings out few features of ‘break in Monsoon’-
- Increase in temperatures over plains of Northwest India.
- Shift of Monsoon trough to the foothills of Himalayas and should remain there for at least two days.
- General decrease of rainfall over major parts of the country including west coast.
- No signs of easterly current over Gangetic plains up to 500 ft.
- Increase in rainfall over the southern peninsula.
- Absence of any disturbance in the Bay of Bengal.
- Westwards moving low pressure areas at low latitudes in Bay of Bengal.
- Heavy showers take place in pockets of the Himalayas but not simultaneously across the length of the foothills.
- In the Himalayan range , places lying in the east of 85°E longitude are more susceptible to heavy showers than in the west of it.
Monsoon is normally revived by the formation of a low pressure area or remnants of a typhoon entering Bay of Bengal from the South China Sea. However, both these conditions are inconspicuous at present. Looking at the present scenario, Monsoon activity is unlikely to revive in another week or so.
