MAIN EVENTS

·      The monsoon trough at mean sea level (msl) continued to remain close to the foothills of the Himalayas leading to fairly widespread rainfall with isolated heavy to very heavy falls along the foothills and adjoining northeastern states and Gangetic plains. Southeast peninsula also recorded good rainfall activity during the week.

·      There was subdued rainfall activity over the remaining parts of the country.

METEOROLOGICAL ANALYSIS

Ø      The axis of the monsoon trough at mean sea level (amsl) remained close to the foothills of the Himalayas during the week.

Ø      An off-shore trough at mean sea level ran from Karnataka coast to Kerala coast. However, the mean sea level pressure gradient along the west coast continued to be weak.

Ø      Last week’s upper air trough from Sub-Himalayan West Bengal & Sikkim to north Bay of Bengal persisted on 17^th and extended upto 2.1 Km above mean sea level. It was seen as a cyclonic circulation over West Bengal and adjoining Bangladesh extending upto mid-tropospheric level and tilting southwestward with height on 18^th. It lay over Gangetic West Bengal and  adjoining Jharkhand on 19^th. It lay over  East Uttar Pradesh and neighbourhood but extended upto 4.5 Km amsl on 20^th and upto lower tropospheric levels during 21^st to 23^rd.

Ø      Last week’s trough in lower tropospheric levels from central Pakistan to northeast Arabian Sea with embedded circulation over central and southeast Pakistan persisted during the week.

Ø      A cyclonic circulation lay over Jammu & Kashmir and neighbourhood on 17^th in lower levels and moved away eastwards on 18^th.

Ø      Another cyclonic circulation lay over Haryana and neighbourhood in lower levels on 20^th& 21^st, over Uttarakhand and neighbourhood on 22^nd & 23^rd.

Rainfall

Ø     Widespread/ fairly widespread rain/thundershower occurred over Arunachal Pradesh, Assam & Meghalaya, West Bengal & Sikkim, Bihar, East Uttar Pradesh and Uttarakhand during many days of the week. The southwest Monsoon was active/vigorous for many days over Bihar & East Uttar Pradesh and for a few days over the remaining sub-divisions. Scattered to fairly widespread rainfall also occurred over Nagaland, Manipur, Mizoram & Tripura during the week.

Ø     Fairly widespread rainfall occurred over Konkan & Goa, Kerala, Lakshadweep and Andaman & Nicobar Islands during many days of the week.

Ø     Fairly widespread rainfall occurred over Vidarbha during second half of the week.

Ø     Isolated to scattered rain/thundershower occurred over remaining parts of the country during many days of the week.

Ø     The details of the rainfall distribution/activity during the week are given in Table-1.

Rainfall During The Week (For the week ending on 23^rd July, 2008)

     Rainfall was excess/normal in 13 and deficient/scanty in 23 out of 36 meteorological sub-divisions (Actual: 45.0 mm, Normal: 67.6 mm and Departure: -33%).

Cumulative Seasonal Rainfall (1^st June to 23^rd July, 2008)

Rainfall was excess/normal in 21 and deficient/scanty in 15 out of 36 meteorological sub-divisions. (Actual: 370.0 mm, Normal: 378.1 mm and Departure: -2%).

The sub-division-wise weekly and seasonal rainfall distribution is presented in the enclosed map.

  District-wise distribution of excess, normal, deficient and scanty rainfall is shown in Table-2. A comparative data of cumulative seasonal rainfall during the corresponding period of last five years is given in Table-3.

Outlook For The Week Ending On 30^th July 2008

·      Gradual southward shifting of monsoon trough likely. Consequently, a low pressure area is likely to form over westcentral and adjoining northwest Bay of Bengal around 27^th.

·      Under this scenario, the rainfall activity is likely to decrease gradually along the foothills, adjoining northern plains and northeastern states.

·      The rainfall activity is likely to increase over the south and adjoining central India, specially north Andhra Pradesh, Maharashtra and Gujarat.