All-India rainfall slips back into deficit

The belt of scattered rains progressing from the Equatorial Indian Ocean has already hit Sri Lanka with the persistent drizzle playing spoilsport with the scheduled one-day international cricket match between the hosts and the touring Indians.
This rain belt is seen by various weather models to push north progressively to foray into extreme south peninsular India. The extent of coverage in the southern States would be decisive in terms of impact on the all-India rainfall, which has slipped back into deficit according to latest update.
India Meteorological Department (IMD) said in a special update on Monday that the cumulative seasonal rainfall as on June 24 had posted a deficit of one per cent. This made for an abrupt reversal from a comfortable surplus of two per cent till only four days back. DRY RUN CONTINUES
This is being attributed to another bout of dry run over northwest and west-central India close on the heels of a weeklong rain spell shutting out. There is hardly any sign of any significant wave coming back to these regions, given that the withdrawal of monsoon is set to begin from Rajasthan around September 1.
But indications are the rest of the country would continue to experience scattered heavy to moderate rainfall. The latest update from the Climate Prediction Centre of the US National Weather Services mentions about ‘increased chances of rains stretching from Equatorial Indian Ocean to the Philippines during the ongoing week’ (August 26 to September 1).
Thus the rain belt moving into peninsular India over the next few days would move east into the Bay of Bengal (to the detriment of north peninsula) and progressively into South China Sea and Northwest Pacific. Extended forecast for the week ending September 8 showed a northward progression of this rain belt.
This northward progression would be confined mostly over the Bay, and in later stages, to the northern fringes of the southeast coast (coastal areas of Orissa and West Bengal) during the forecast period.
This will effectively rule out any rain for the northern peninsular India whose waxing and waning weather and the fate of the larger monsoon have come to be inextricably linked. SURPLUS IN NORTHWEST
The IMD update said the rainfall distribution till date has been skewed over the four broad homogenous regions with only Northwest India managing a tidy surplus of 19 per cent. Central India (-7 per cent), South Peninsula (-6 per cent) and the Northeast (-5 per cent) bled the rainfall charts in that order.
The number of Met subdivisions recording excess and normal rainfall (again mostly confined to north and northwest) are 30. The rest six are in deficit, with Vidarbha (-20 per cent) the latest to join the list.
The rest featured on the list are (deficits in percentage in brackets): Marathawada (-44); Kerala (-31); Nagaland-Manipur-Mizoram-Tripura (-28); North Interior Karnataka (-27); and Assam and Meghalaya (-21). Of this, Kerala is expected to benefit from the approaching ran belt from the south and southwest.
The IMD update went on to add that model predictions suggested subdued rainfall over northwest and central India during the next week. But East and Northeast India may experience widespread rains with heavy to very heavy falls during the same period