SIGNIFICANT WEATHER

• Cyclonic storm ‘Mahasen’ formed over southeast Bay of Bengal on 11^th May 2013.

• Thunderstorms occurred over Jammu & Kashmir, Tamil Nadu, Uttarakhand, Nagaland, Manipur, Mizoram & Tripura and West Bengal & Sikkim for many days; over Assam, Andhra Pradesh, Karnataka and Himachal Pradesh for a few days and over Kerala, Rajasthan, Punjab, Haryana, Chandigarh & Delhi, Madhya Pradesh, Uttar Pradesh, Jharkhand and Chhattisgarh for one or two days of the week.

• Heat wave conditions prevailed over some parts of Vidarbha, East Uttar Pradesh, Chhattisgarh, Madhya Pradesh, interior Andhra Pradesh, interior Odisha and Tamil Nadu for one or two days of the week.

• The highest maximum temperature of 46.7°C was reported at Nagpur (Maharashtra) on 9^th May 2013 in the plains of the country during the week.

METEOROLOGICAL ANALYSIS

• Last week’s low pressure area over southeast Bay of Bengal & neighbourhood persisted over the same area on 9^th May associated cyclonic circulation extending upto mid-tropospheric level. The low pressure area intensified into depression at 1430 hours IST of 10^th May and moving northwards intensified into deep depression at 1730 hours IST of same day. The deep depression further moved northwestwards concentrated into cyclonic storm ‘Mahasen’ at 0830 hours IST of 11^th May and lay centred near Latitude 7.0^o N and Longitude 90.5^o E, near Latitude 10.0^o N and Longitude 87.5^o E at 0830 hours IST of 12^th, near Latitude 11.8^o N and Longitude 86.4^o E at 0830 hours IST of 13^th, near Latitude 13.5^o N and Longitude 85.5^o E at 0830 hours IST of 14^th and moving north-northeastwads it lay centred near Latitude 16.5^o N and Longitude 87.0^o E at 0830 hours IST of 15^th May 2013 about 850 Km northwest of Port Blair and 430 Km south-southeast of Paradip.

• A trough in low level ran East Uttar Pradesh to east Assam on 9^th on 10^th, from East Uttar Pradesh to Tripura on 11^th across Bihar & Gangetic West Bengal and became less marked on 12^th May 2013.

• A trough in the lower level ran Vidarbha to south Tamil Nadu on 9^th May across interior Karnataka persisted over the same area on 10^th May, from Jharkhand to Tamil Nadu on 11^th across Chhattisgarh & Andhra Pradesh, from Bihar to Tamil Nadu on 12^th May across Jharkhand & Chhattisgarh and became less marked on 13^th May 2013.

• An induced cyclonic circulation lay over central Pakistan and adjoining area of Rajasthan on 10^th in lower levels, over Haryana & neighbourhood on 11^th May extending upto 1.5 Km above mean sea level persisted over the same area on 12^th May and became less marked on 13^th May 2013.

• An upper air cyclonic circulation lay over east Arunachal Pradesh and adjoining areas of Assam on 13^th May in lower level and persisted over the same area on 14^th May and became less marked on 15^th May 2013.

RAINFALL

• Widespread rainfall occurred over Nagaland, Manipur, Mizoram & Tripura for many days; over Arunachal Pradesh and Assam & Meghalaya for a few days and over Andaman & Nicobar Islands, Uttarakhand and Himachal Pradesh for one or two days of the week.

• Fairly widespread rainfall occurred over Jammu & Kashmir for many days; over Assam & Meghalaya and Nagaland, Manipur, Mizoram & Tripura for a few days and over Andaman & Nicobar Islands, Arunachal Pradesh, West Bengal & Sikkim and North Interior Karnataka for one or two days of the week.

• Scattered rainfall occurred over Sub-Himalayan West Bengal & Sikkim for many days; over Andaman & Nicobar Islands and Arunachal Pradesh for a few days and over Assam & Meghalaya, Jharkhand, Punjab, Coastal Andhra Pradesh, Coastal Karnataka and South Interior Karnataka for one or two days of the week.

• Isolated rainfall occurred over Odisha, Tamilnadu & Puducherry and Kerala for most days; over Gangetic West Bengal, Coastal Andhra Pradesh and Rayalaseema for many days; over Jharkhand, Bihar, Haryana, Chandigarh & Delhi, Himachal Pradesh, Jammu & Kashmir, Telangana and Lakshadweep for a few days and over Nagaland, Manipur, Mizoram & Tripura, Uttar Pradesh, Uttarakhand, Punjab, Rajasthan, West Madhya Pradesh, Saurashtra & Kutch, Konkan & Goa, Madhya Maharashtra, Vidarbha and Karnataka for one or two days of the week.

• Weather was mainly dry over the rest region of the country.

Sub-divisionwise daily distribution of rainfall is shown in Table-1.

MAXIMUM TEMPERATURE

During the week the maximum temperatures were-

• Markedly below normal over Arunachal Pradesh, Uttarakhand, Haryana Chandigarh & Delhi, Punjab, Himachal Pradesh and Jammu & Kashmir for one or two days of the week.

• Below normal to appreciably below normal over Arunachal Pradesh and Assam & Meghalaya for a few days and over Nagaland, Manipur, Mizoram & Tripura, West Bengal & Sikkim, West Uttar Pradesh, Uttarakhand, Haryana, Chandigarh & Delhi, Punjab, Himachal Pradesh, Jammu & Kashmir, Rajasthan, Madhya Pradesh and South Interior Karnataka for one or two days of the week.

• Above normal to appreciably above normal over Telangana, Rayalaseema and Tamil Nadu & Puducherry for many days; over Odisha, Jharkhand, Bihar, East Uttar Pradesh, Chhattisgarh and Coastal Andhra Pradesh for a few days and over Andaman & Nicobar islands, Gangetic West Bengal, West Uttar Pradesh, Uttarakhand, Haryana, Chandigarh & Delhi, Punjab, Himachal Pradesh, Jammu & Kashmir, East Madhya Pradesh, Madhya Pradesh, Madhya Maharashtra and Vidarbha for one or two days of the week.

• Near normal over rest region of the country.

Sub-divisionwise daily distribution of minimum temperature is shown in Table-1.

Rainfall During The Week (For the week ending on 15^th May, 2013)

Rainfall was excess/normal in 9, deficient/scanty in 25 and no rain in 2 out of 36 meteorological sub-divisions. (All India Actual: 12.6 mm, Normal: 14.3 mm and Departure: -12%).

Cumulative Seasonal Rainfall (1^st March to 15^th May, 2013)

Rainfall was excess/normal in 13 and deficient/scanty in 23 out of 36 meteorological sub-divisions. (All India Actual: 69.7 mm, Normal: 96.5 mm and Departure: -28%).

The sub-division wise weekly and seasonal rainfall distribution is presented in Fig.1 and Fig.2.

Statewise distribution of number of districts with excess, normal, deficient, scanty and no rainfall is shown in Table-2.

A comparative data of cumulative seasonal rainfall during the corresponding period in the last five years is given in Table-3.

Outlook For The Week Ending on 22^nd May, 2013

• Southwest monsoon would advance over Andaman Sea and south Bay of Bengal during next 2-3 days.

• Rain/thundershowers would occur at many places over northeastern States and Andaman & Nicobar Islands during the week.

• Rain/thundershowers would occur at one or two places over south peninsular India during many days of the week.

• Maximum temperature would rise by 2-3°C over many parts of northwest, central and east India during 1^st half of the week leading to heat wave over some parts of above regions.

• Weather would be mainly dry over rest parts of the country during many days of the week.