Southwest Monsoon in India is conceived as a complex phenomenon. A cautious approach is generally taken before announcing onset or withdrawal. Just as the onset is eagerly awaited, even withdrawal is keenly followed.
Withdrawal symptoms of Southwest Monsoon are clearly visible now. According to the latest weather update, seems like it has already commenced from west Rajasthan.
Monsoon in India
Monsoon season spans over the Indian region from June to September and holds a Long Period Average (LPA) of 89 cm of rain. It has few built-in features like the calamity over Uttarakhand in 2013 and the floods in Jammu & Kashmir this year. Monsoon never behaves in a normal manner, as rainfall distribution mostly remains uneven both in space and time. It always leaves one guessing as it brings anxious moments, anticipatory worries and jitters.
July and August are generally the active Monsoon months for the entire country. June is the onset month which witnesses an outburst of rain while, September is the withdrawal month, receiving more of sporadic rain.
Withdrawal of Southwest Monsoon
Withdrawal is generally not attempted before 1st of September and commences from extreme west Rajasthan. A shortfall of Monsoon brings a host of problems, similarly even delay of withdrawal damages crops.
As Southwest Monsoon approaches the withdrawal phase from a particular region, certain conditions become prevalent- change of wind pattern, reduction in cloud cover, decrease in humidity, cessation of rain, appearance of dew and reduction in temperatures.
Reversal of wind pattern- Winds over Rajasthan have already turned westerly, indicating replacement of moist air by cool and dry air.
Cessation of rain- Bikaner, Barmer and Bhuj have been completely dry since last 12 days. Jodhpur and Jaisalmer have not received any rain since last 6 days.
Dip in humidity- Humidity across west Rajasthan has come down from 85-90% in first week of September to 75-80% at present.
Establishment of anti-cyclone- In Northwest India winds have started blowing in clockwise direction but proper establishment of anti-cyclone takes more time. At present the winds have given rise to a ridge i.e. clockwise movement of winds without making a proper circle.
Monsoon trough- Monsoon trough is lessmarked and has shifted closer to the foothills and is likely to remain there.
Monsoon Index- It is the pressure difference between Trivandrumand Mumbai. At present the pressure difference has reduced to 0.9 hPa against the normal of 3 to 4 hPa during active Monsoon period.
Status on September 10
| Name of Place | Minimum in oC | Dew Point | Humidity in % | Sky condition |
| Sri Ganganagar | 27 | 26.2 | 95 | Partly Cloudy |
| Bikaner | 27.2 | 23.1 | 78 | Partly Cloudy |
| Jaipur | 26.2 | 24.5 | 90 | Partly Cloudy |
| Jaisalmer | 27.8 | 24 | 80 | Partly Cloudy |
| Barmer | 27.4 | 24.5 | 84 | Partly Cloudy |
| Udaipur | 24.4 | 22.7 | 90 | Partly Cloudy |
Status on September 17
| Name of Place | Minimum in oC | Dew Point | Humidity in % | Sky condition |
| Sri Ganganagar | 26 | 23 | 83 | Clear |
| Bikaner | 26.6 | 21.2 | 72 | Clear |
| Jaipur | 25.8 | 21.6 | 78 | Clear |
| Jaisalmer | 25.8 | 21.6 | 78 | Clear |
| Barmer | 27.4 | 21.7 | 71 | Clear |
| Udaipur | 23.4 | 21.6 | 90 | Clear |
From the above table it is evident that the period of retreat of Monsoon has started from west Rajasthan. The figure above clearly shows that it has retreated also from Kutch, parts of Punjab and Haryana. Gradually monsoon will retreat from Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Delhi/NCR, west Uttar Pradesh, east Rajasthan and Gujrat in next few days.
