The cyclonic circulation over central parts of western Madhya Pradesh and adjoining eastern Rajasthan extends up to 7.6 km above sea level and tilts towards the southwest with height. The cyclonic circulation over the South Gujarat region and surroundings during the past week was over Saurashtra and surroundings and extended up to 5.8 km above sea level, with a slope towards the southwest with the height on September 2, 2021; it was over the Northeast Arabian Sea &. Last week's low from south Gujarat to south coastal Andhra Pradesh, between 3.1 and 5.8 km above sea level, became less pronounced on September 2, 2021.
A cyclonic circulation developed over the west central and adjoining southwest Bay of Bengal off the south coast of Andhra Pradesh-North Tamilnadu between 1.5 km and 3.1 km above mean sea level on the 2nd. September 2021; it lay over coastal Andhra Pradesh and the surrounding area between 1.5 and 4.5 km above mean sea level, inclined to the south with a height of 3; On September 4, 2021, it became less noticeable. A westerly disturbance as a low- to mid-tropospheric westerly with an axis at 5.8 km above mean sea level ran approximately along Longo.
A trough in western parts with its axis at 3.1 km above mean sea level ran roughly along Long. A cyclonic circulation lay over northern Pakistan and surroundings at 1.5 km above mean sea level on 8 September 2021.
Andaman &
Arunachal Pradesh
Gangetic West Bengal
Odisha
Jharkhand
Bihar
East Uttar Pradesh
West Uttar Pradesh
Uttarakhand
Punjab
Himachal Pradesh
West Rajasthan A
East Rajasthan A
West Madhya Pradesh
East Madhya Pradesh
Gujarat Region A
Saurashtra &
Konkan & Goa A
Madhya Maharashtra
Marathawada A
Vidarbha
Chhattisgarh
Telangana
Rayalaseema A
Coastal Karnataka
North Interior Karnataka
South Interior Karnataka
Kerala & Mahe A
Lakshadweep A
During the week ending 8 September 2021, above normal rainfall activity was reported over India and weekly cumulative rainfall across India Monsoon in % deviation from its long period average (LPA) during the week was +15% (see Appendix I, for week by week all India rainfall progress and seasonal cumulative rainfall in % departure from LPA). Such above normal rainfall activity for India as a whole had occurred after a gap of 5 consecutive weeks since the week ending 28th July 2021 where all India % departure from LPA was observed weekly also +15% ie. the increased rainfall activity was due to a )Remnants of cyclonic circulation of the low pressure area from the previous week extending up to mid-tropospheric levels which was located over Saurashtra and the neighborhood on 2nd Sept moved very slowly westwards to the Kutch areas on 6 .September. b) Formation of yet another low pressure area northwest and adjoining Westcentral Bay of Bengal off south Odisha-north Andhra Pradesh coasts on 6th which then moved as a well-marked low pressure area to southwest Madhya Pradesh and quarter on 8 September 2021 across of Odisha and South Chhattisgarh c) Monsoon trough was also south of its normal position due to the presence of these two systems d) Along with these favorable synoptic features, an east-west shear zone was also seen along latitude 10°N on 2 Sept., which moved to 18°N on 8 Sept., in the lower and middle tropospheric levels tilt southward with height.
The weekly cumulative rainfall for the country as a whole for the week ending September 1 is 15% above the long-term average (LPA), while the seasonal cumulative rainfall from June 1 to September 1, 2021 is 7% below the LPA. Details of the rainfall distribution over the four broad geographical regions of India are given in Table 1 and the rainfall per week and per season is subdivided in Appendix II and III.
Large scale features
3 | The site of the re-emergence of La Nina conditions at or after the end of the monsoon season. The latest forecast from MMCFS and other global models together indicate that negative IOD conditions over the Indian Ocean are likely to continue for the remainder of the monsoon season. It is likely to move eastward with increased amplitude and enter phase 4 during the first half of week 2.
Then it will likely propagate further eastward within Phase 4 with gradual reduction in amplitude during the remainder of week 2. It will most likely be active and lie south of its normal position or near normal during the week. A low pressure area is likely to form over North and adjoining Central Bay of Bengal around 11 September 2021 and it will concentrate heavily into a depression over northwest and adjoining west-central Bay of Bengal around 13 September 2021.
It is most likely to move west-northwest across Odisha, north Chhattisgarh and north Madhya Pradesh. Under the influence of cyclonic circulation over West Madhya Pradesh; Fairly widespread rainfall with isolated heavy to very heavy rainfall is likely over Southeast Rajasthan and West Madhya Pradesh during September 09-12. Rainfall activity is likely to increase with isolated heavy rain over south Haryana, southwest Uttar Pradesh during September 10 to 11.
Isolated heavy to very heavy rainfall is likely over Uttarakhand and isolated heavy rainfall is likely over Jammu and Himachal Pradesh division during the first half of the week. Reduced rainfall activity is most likely to continue over the southern interior peninsula of India during the first half of the week and increase thereafter with scattered to fairly widespread rain. Isolated heavy rainfall is likely over Karnataka, Kerala, Telangana and Andhra Pradesh on September 13 and 14.
Rainfall totals are very likely to be above normal over northwest and central India, near normal over east India and below normal over northeast and south peninsular India. The monsoon trough is very likely to be active and near normal/south of its position most days of the week. Fairly widespread to widespread rainfall with isolated heavy rainfall very likely over NW, Central and East India on most days.
Conditions are not likely to be favorable for the onset of monsoon withdrawal from parts of northwest India before the end of week 2. 5 | P a g e Based on the guidance of numerical models, it can be concluded that there is a high probability of the formation of a low pressure area over Northern and adjacent central BoB around September 11. A new low pressure is also likely to develop over the central parts of the BoB during the beginning of week 2. The next weekly update will be released next Thursday, i.e. of subdivisions and % area of the country.
PERCENT DISTRIBUTION OF DISTRICTS IN PREVIOUS YEARS SINCE June 1 OF DISTRICTS FROM THE.
