Southeast India, especially Tamil Nadu and Puducherry experienced unprecedented rainfall activity during November and early December 2015 leading to devastating flood over Tamil Nadu. The megacity of Chennai was worst affected during the end of November and early part of December. The weather systems leading to this flood situation, forecast performance of IMD and the monitoring and prediction system of
IMD including the observational network are presented in the following sections.
1. Weather systems affecting southeast India during November 2015 and realised rainfall
The northeast monsoon season (NEM) of October to December (OND) is the chief rainy season for the southeastern parts of peninsular India (Tamil Nadu and Puducherry). This season is also the chief cyclone season over the North Indian Ocean and hence, low pressure systems forming over the Bay of Bengal and moving westwards contribute significantly towards the NEM rainfall over meteorological sub-division of Tamil Nadu and
Puducherry (TN&PDC). During the year 2015, the onset of NEM took place on 28 th
October against the normal date of 20 th October. Subsequently, during the month of
November, the following three synoptic scale weather systems affected Tamil Nadu and
Puducherry causing extensive rainfall activity over the region:
(i) Deep Depression over Bay of Bengal (08-10 November 2015)
(ii) Well marked Low pressure area over SouthWest Bay of Bengal (12-18 November
2015)
(iii) Low (28 November-04 December 2015).
Brief history of these weather systems and associated rainfall are presented below:
1.1 Deep Depression over Bay of Bengal (08-10 November 2015)
On 7 th November, a low pressure area formed in the south Bay of Bengal which rapidly concentrated into a deep depression (one stage lower than Tropical Cyclone) on
8th November. The deep depression was associated with strong winds of 55-65 kmph and remained practically stationary very close to the coast of Tamil Nadu for nearly 12 hours during the day time on 9th before crossing north Tamil Nadu coast near Puduchhery in the evening of 9th November. The system retained its intensity nearly for another 15

hours over northern parts of Tamil Nadu. This caused very heavy rainfall (13-24 cm) at a few places with isolated extremely heavy rainfall (>25 cm) over Tamil Nadu and adjoining
Districts of Andhra Pradesh. IMD issued early warnings for track & intensity of the system, heavy rainfall and strong winds. Special warnings for the fishermen off and along Tamil
Nadu coast were also issued well in advance. For this system, bulletins were provided to all concerned states including Tamil Nadu, Puducherry and Andhra Pradesh and the national disaster management agencies including MHA, NDMA, NDRF and also to farmers, fishermen, ports, ships, Indian Navy, Indian Air Force through various means including e-mail, fax and SMS as well as press and electronic media 4-5 days in advance.
INSAT-3D satellite imagery of the system as on 09 th /1130 UTC, Doppler Weather Radar,
Chennai based on 09 th /1400 UTC (just prior to landfall around 1400 UTC) and observed and forecast track (based on 09 th /1200 UTC) are presented in Fig.1(a-b).
Fig.1a INSAT-3D satellite imagery of DD (08-10 Nov 2015) based on 09 th /1130 UTC, Doppler
Weather Radar, Chennai imagery based on 09 th /1400 UTC
Observed and forecast track of
Deep Depression
Fig.1(b) Typical forecast and observed track of Deep Depression.
North Tamil Nadu and adjoining Rayalaseema received heavy to extremely heavy rainfall during 24-hr ending 0300 UTC of 09 th . Neyveli of Cuddalore district in north coastal Tamil
Nadu recorded highest 24 hr rainfall amount of 48 cm ending at 10 th /0300 IST. Tirumala

in Rayalaseema recorded extremely heavy rainfall of 30 cm during the same period.
Spatial distribution of 24-hr heavy rainfall occurences as on 0300 UTC of 08-11
November 2015) is depicted in Fig.1b. (Description of rainfall terminologies: Rainfall amount : Heavy : 64.5 to 124.4 mm, Very Heavy : 124.5 to 244.4 mm and Extremely
Heavy : ≥244.5 mm; Spatial distribution : Isolated (ISOL) : 1-25% of stations reporting rainfall, Scattered (SCT / A few places) : 26-50% of stations reporting rainfall, Fairly
WideSpread (FWS/ Many places) : 51-75% of stations reporting rainfall and Widespread
(WS/ Most places) : 76-100% of stations reporting rainfall during the last 24 hours ending at 0300 UTC of every day).
Fig.1c Rainfall realised in association with Deep Depression (08-10 Nov 2015) (based on
IMD-NCMRWF GPM gauge merged rainfall data)

1.2. Well marked Low pressure area over SouthWest Bay of Bengal
(12-18 November 2015)
In quick succession, a trough of low lay over south Andaman Sea and neighbourhood with associated cyclonic circulation extending upto 3.1 km a.s.l on 12 th .
On 13 th November, it lay over southeast Bay of Bengal and neighbourhood with associated cyclonic circulation extending upto 4.5 km a.s.l. Under its influence, a low pressure area formed over southeast Bay of Bengal on the same day. It became well marked on 14 th and lay over to southwest Bay of Bengal off North Tamil Nadu and adjoining Sri Lanka coasts on 15 th . It lay over southwest Bay of Bengal of north Tamil
Nadu coast with associated upper air cyclonic circulation extending upto mid-tropospheric levels and tilting southwestwards with height on 16 th . Moving northwards, it lay over westcentral and adjoining southwest Bay of Bengal off south Andhra Pradesh
– north
Tamil Nadu coasts on 17 th . On 18 th , it lay as a low pressure area over westcentral Bay of
Bengal off Andhra Pradesh coast with associated upper air cyclonic circulation extending upto 2.1 km a.s.l. It resulted in narrow core of strong winds and very heavy rainfall over north Tamil Nadu and south Coastal Andhra Pradesh and Rayalaseema during 16-18
November. INSAT-3D satellite imagery of the system as on 0000 UTC of 16 th November is shown in Fig.2(a)
Fig.2a INSAT-3D satellite imagery based on 09 th /1130 UTC of the well marked low pressure area during 12-18 November 2015
Associated with this system, rainfall activity occurred over coastal Tamil Nadu during 12-
18 November. Heavy to extremely heavy rainfall occured along the entire north Tamil
Nadu coastal belt during the 24-hr ending 0300 UTC of 16 th and isolated heavy to very heavy rainfall on the other days. Spatial distribution of 24-hr heavy rainfall occurences as on 0300 UTC of 13-19 November 2015) is depicted in Fig.2b.

Fig.2b 24-hr accumulated rainfall as on 0300 UTC of 13-18 November 2015 in association with well marked low of 12-18 Nov 2015 (based on IMD-NCMRWF GPM gauge merged rainfall data)

1.3. Low pressure area (28 November - 04 December 2015)
In a quick succession, two troughs of low pressure developed over southeast Bay of
Bengal during the last week of November which moved westwards towards Tamil Nadu coast. The first trough of low pressure with an associated upper air cyclonic circulation extending upto 3.6 km above mean sea level lay over southwest Bay of Bengal off Tamil
Nadu coast on 28 th November. It persisted over the same region on 29 th . On 30 th , the second trough of low pressure also moved westward and lay over southwest Bay of
Bengal with associated cyclonic circulation in lower tropospheric levels and the first trough merged with the second trough of low pressure. It persisted over the same region till 2 nd
December. Under its influence, a low pressure area formed over southwest Bay of Bengal off Tamil Nadu coast on 3 rd December. The low persisted over the same region on 04 th
December.
Fig.3a INSAT-3D satellite imagery based on 01 st /0600 UTC of the trough of low pressure during 28 November -03 December 2015
Associated with this system, rainfall activity occurred over coastal Tamil Nadu during 29
November-03 December. Over north coastal Tamil Nadu and Puducherry, heavy to extremely heavy rainfall occured along the entire coastal belt during the 24-hr ending 0300
UTC of 02 nd December, very heavy rainfall over a few places on 01 st December and isolated heavy to very heavy rainfall on the other days. Spatial distribution of 24-hr heavy rainfall occurences as on 0300 UTC of 30 November – 03 December 2015) is depicted in
Fig.3b.

Fig.3b 24-hr accumulated rainfall as on 0300 UTC of 30 Nov – 03 Dec 2015 in association with trough of low off Tamil Nadu coast (28 November – 03 December 2015) (based on IMD-NCMRWF GPM gauge merged rainfall data)

2. Monitoring, Prediction and Bulletins issued by IMD
All the three synoptic systems were monitored & predicted by IMD continuously since their formation. Despite the system forming and intensifying close to the coast and making landfall within 36 hrs of formation, forecast of its genesis, movement, intensity, point & time of landfall, as well as associated adverse weather like heavy rain and strong wind were predicted well by IMD with sufficient lead time to enable civil administrators and disaster managers to take necessary mitigatory actions. Movement towards north Tamil
Nadu coast, maximum intensity it would attain (DD / Cyclonic Storm (CS; MSW: 34-47 kts), landfall near to Puducherry coast and expected adverse weather such as extremely heavy rainfall along north coastal Tamil Nadu were predicted by IMD even before the formation of the systems. All the systems were monitored continuously by satellite based observations available at every half-an-hour interval. Enhanced INSAT-3D imageries formed the basic satellite input for cyclone monitoring. As the system formed close to the coast, the system was monitored with meteorological buoys, coastal and ship observations from the genesis stage onwards in addition to satellite based observations.
Special hourly synoptic observations were taken along Tamil Nadu and Puducherry coasts for the Deep Depression (08-10 Nov) from 08 th morning onwards. As the system moved within the range of coastal radars, continuous radar observations were also taken at
Doppler Weather Radar (DWR) facilities at Karaikal and Chennai. Observations from
Automatic Weather Stations (AWS) and High Wind Speed Recorders (HWSR) installed along coastal Tamil Nadu also provided crucial data for successful monitoring of the systems. Satellite data products and scatterometry products available from other leading meteorological services of the globe were also used for location, intensity and structure estimations. Details of observational networks of conventional surface and upper air observatories, Radar, Automatic Weather Stations, High Wind Speed Recorders over
Tamil Nadu region are given in Annexure I.
Various national and international Numerical Weather Prediction (NWP) models and dynamicalstatistical models including IMD’s and NCMRWF’s global and meso-scale models, dynamical statistical models were utilized to predict the genesis, track and intensity of the systems. The digitized forecasting system of IMD was utilized for analysis and comparison of various model guidances, decision making process and warning products generation and dissemination.
Adverse weather associated with these systems were predicted well in advance.
Daily weather bulletins updated every 6-hrs was issued by National Weather Forecasting
Centre at New Delhi. A probabilistic forecast on possible cyclogenesis over Bay of Bengal within 48-72 hrs was issued by RSMC New Delhi every day based on 0300 UTC analysis.
6-hrly RSMC and National bulletins were issued from the Depression stage onwards.
Details of bulletins issued by various IMD offices including Regional Meteorological Centre
Chennai are given in Annexure II . Salient features of heavy rainfall warnings issued by
IMD as shown in Annexure III.
Detailed report on heavy rainfall warnings issued and heavy rainfall realised over Tamil Nadu and Puducherry during November and early
December 2015 are given in Annexure IV.

Annexure I :
Observational Network of IMD in Tamilnadu and Puducherry
(a) SURFACE (DEPARTMENTAL) STATIONS
Sl. Station
1 CHENNAI (NUNGAMBAKKAM)
2 CHENNAI (MINAMBAKKAM) (A)
3
COIMBATORE (PEELAMEDU)
(A)
4 CUDDALORE
5 KODAIKANAL
6 KANYAKUMARI
Station Index District
43278 CHENNAI
43279 CHENNAI
43321 COIMBATORE
43329 CUDDALORE
43339 DINDIGUL
43377 KANYAKUMARI
43360 MADURAI
Class of
Observatory
Class - I
Class - I
Class - I
Class - I
Class - I
Class - I
Class - IIa
Sl.
1
2
3
4
7 MADURAI (A)
8 NAGAPATTINAM
9 PAMBAN
10 SALEM
11 ADIRAMAPATINAM
12 TIRUCHIRAPALLI (A)
13 VELLORE
Station
VALPARAI(UPASITRI)
DHARMAPURI
ERODE
KARUR PARAMATHI
5
6
7
MADURAI
VEDARANYAM
UTHAGAMANDALAM
(OOTACAMUND)
COONOOR 8
9 ARIYALUR
10 KUDIMIAMALAI
43301
43338
43342
43359
43349
43317
43318
43324
43345
43347 NAGAPATTINAM
43363 RAMNATHAPURAM
43325 SALEM
43348 THANJAVUR
43344 TIRUCHIRAPPALLI
Class - I
Class - I
Class - IIa
Class - I
Class - I
43303 VELLORE Class - IIa
(b) SURFACE (NON-DEPARTMENTAL) STATIONS
Station Index District
Class of
Observatory
43341 COIMBATORE Class - IIb
DHARMAPURI
ERODE
KARUR
MADURAI
NAGAPATTINAM
NILGIRIS
NILGIRIS
PERAMBALUR
PUDUKKOTTAI
Class - IIb
Class - IIb
Class - IIbo
Class - IIb
Class - IIb
Class - IIb
Class - IIb
Class - IIb
Class - IIdo
11 MANAMELKUDI
12 YERCAUD
13 TANJAVUR
14 PERIAKULUM
15
16
THOOTHUKUDI NEW
PORT
TIRUCHIRAPALLI
TOWN
17 PALAYAMKOTTAI
18 TIRUTTANI
19 TIRUPPATTUR
20 KOVILANGULAM
---
43340
43330
43356
43379
43343
43376
43277
43302
43358
PUDUKKOTTAI
SALEM
THANJAVUR
THENI
THOOTHUKUDI
TIRUCHIRAPPALLI
TIRUNELVELI
TIRUVALLUR
VELLORE
VIRUDHUNAGAR
Class - IIb
Class - IIb
Class - IIb
Class - IIb
Class - Io
Class - VIc
Class - IIb
Class - IIbo
Class - IIb
Class - IIb

(c) RS / RW STATIONS
Sl.
#
1
Station
Station
Index
District
CHENNAI
(MINAMBAKKAM) (A)
43279 CHENNAI
(d) PBO STATIONS
Sl.
#
Station
1
Chennai
(Minambakkam)
2 Tiruchirapalli
Class of
Observatory
Class - I
Station
Index
District
43279 CHENNAI
Class of
Observatory
Class - I
43344 TIRUCHIRAPPALLI Class - I
(e) HWSR STATIONS
Sl. # Station
1
Chennai
(Minambakkam)
Station
Index
District
43279 CHENNAI
(f) RADAR STATIONS
Sl. # Station
1 Chennai
2. Kariakal
(g) HWSR STATIONS
Station
Index
District
43279 CHENNAI
43346 Puducherry
Sl. # Station
1
CHENNAI
(MINAMBAKKAM) (A)
Station
Index
District
43279 CHENNAI
Class of
Observatory
Class - I
Class of
Observatory
Class - I
Class-I
Class of
Observatory
Class - I

(h) AUTOMATIC WEATHER STATIONS
Sr.No. STATION Name
26
27
28
29
22
23
24
25
18
19
20
21
14
15
16
17
30
31
32
33
34
35
36
37
7
8
9
10
11
12
13
1
2
3
4
5
6
SITE_TYPE DISTRICT INST_TYPE
ADIRAMAPATTINAM
ADUTHURAI_AGRO
ARIYALUR
CHENNAI
CHIDAMBARAM
COIMBATORE_AGRO
COONOOR
ENNORE PORT
ERODE_ISRO
HOSUR
KALAVAI
KANCHIPURAM_ISRO
KOVILPATTI
AWS Thanjavur
AWS
AWS
AWS
AWS
Thanjavur
Ariyalur
Chennai
Cuddalore
AGRO AWS Coimbatore
AWS
AWS
AWS
AWS
AWS
AWS
AWS
Nilgiris
Chennai
Erode
Sutron
Astra
Astra
Sutron
Sutron
Astra
Astra
Astra
ISRO_Astra
Krishnagiri Astra
Kanchipuram Sutron
Kanchipuram ISRO_Astra
Tuticorin Port Astra
MADHAVARAM_AGRO AGRO AWS Chennai
MADURAI_ISRO AWS Madurai
MAILAM AWS
MEENAMBAKKAM_ISRO AWS
Vellupuram
Chennai
NAMAKKAL
NATHAM_ISRO
NEYVELI
NEYYOOR
AGRO AWS Namakkal
AWS
AWS
AWS
Dindigul
Cuddalore
Astra
ISRO_Astra
Sutron
ISRO_Astra
Astra
ISRO_Astra
Astra
Kanyakumari Sutron
OOTY_AGRO
PAIYUR AGRO
PECHIPARAI_AGRO
PERAMBALUR
PERIAKULAM
RIMC CHENNAI
THIRUCHENDUR
THUVAKUDI_ISRO
AGRO AWS Nilgiris
AGRO AWS Dharmapuri
AGRO AWS Kanyakumari Astra
AWS Perambalur Astra
AWS
AWS
AWS
AWS
Thani
Chennai
Toothukudi
Trichy
Astra
Astra
Astra
Sutron
Sutron
ISRO_Astra
TIRUNELVELI AWS
TIRUTTANI PTO_ISRO AWS
TIRUVANNAMALAI_ISRO AWS
TUTICORIN PORT AWS
VEDASANDUR
VIRINJIPURAM_ISRO
VIRUDHUNAGAR
YERCAUD_ISRO
AWS
AWS
AWS
AWS
Tirunelveli
Trichy
Astra
ISRO_Astra
Tiruvannamalai ISRO_Astra
Toothukudi Sutron
Dindigul
Vellore
Sutron
ISRO_Astra
Virudhunagar Astra
Salem ISRO_Astra

(i) AUTOMATIC RAINGAUGE STATIONS -
8
9
10
11
12
13
1
2
3
4
5
6
7
14
15
16
17
28
29
30
31
24
25
26
27
18
19
20
21
22
23
32
33
34
35
36
37
Sr.No. STATION Name SITE_TYPE DISTRICT
ANDIPATTI
ANNA UNIVERSITY
ARG
ARG
ARANI
BODINAYAKANUR
ARG
ARG
CHEMBARAMBAKKAM ARG
CHETTYKULAM ARG
CHEYYAR ARG
CHEYYUR
DENKANIKOTTAI
DEVAKOTTAI
DEVALLA
DHARAPURAM
DINDIGUL
GOBICHETTY
PALAYAM
GRAND ANAICUT
HARUR
HINDUSTAN
UNIVERSITY
HVF AVADI
JAYAMKONDAM
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
KALLAKURICHI
KAMUDHI
KANGEYAM
KARUMANDURAI
KARUR
KAYATHAR
KOLLIDAM
KOLLIMALAI
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
KOMARAPALAYAM
KUDAVASAL
ARG
ARG
KULITHALAI ARG
KVK KATTUPAKKAM ARG
LALPET ARG
LMOIS KOLAPAKKAM ARG
LOWER KOTHAIYAR ARG
MANALMEDU ARG
MANAMADURAI
MANAPARAI
ARG
ARG
INST_TYPE
Theni
Chennai
Jinyang
Jinyang
Tiruvallur
Theni
Kanchipuram
Perambalur
Jinyang
Jinyang
Jinyang
Jinyang
Tiruvannamalai Jinyang
Kanchipuram
Krishnagiri
Sivagangai
Nilgiri
Tiruppur
Dindigul
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Erode
Thanjavur
Dharmapuri
Jinyang
Jinyang
Jinyang
Kanchipuram Jinyang
Tiruvallur
ARIYALUR
Jinyang
Jinyang
Villupuram Jinyang
Ramanathapuram Jinyang
Tiruppur
Salem
Jinyang
Jinyang
Karur
Thoothukudi
Nagapattinam
Namakkal
Namakkal
Thiruvanur
Karur
Tiruvallur
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
CUDDALORE
Kanchipuram
Kanyakumari
Nagapattinam
Sivagangai
Trichy
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang

MANIMUTHAR DAM
MELUR
MUTHUPETTAI
NAGERCOIL
NILAKOTTAI
ORATHANADU
P N PALAYAM
PALACODE
PAPPIREDDI
PERUNDURAI
POCHAMPALLI
POLLACHI
POONAMALLEE
PUDUKOTTAI
PUZHAL
R.K.PET
RADHAPURAM
RAJAPALAYAM
RASIPURAM
SANKARANKOIL
SATHYABAMA
UNIVERSITY
SATTANKULAM
SENTHURAI
SIVAKASI
TARAMANI
THIRUKOILUR
THIRUMAYAM
THURAIYUR
TIRUVALLUR
UPPER BHAVANI
VADIPATTI
VALINOKKAM
VANIYAMBADI
VAZHAPADI
VEPPANTHATTAI
VRIDHA_CHALAM
YELAGIRI HILL
58
71
72
73
74
67
68
69
70
59
60
61
62
63
64
65
66
47
48
49
50
43
44
45
46
38
39
40
41
42
51
52
53
54
55
56
57
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
ARG
Tirunelveli
Madurai
Thiruvanur
Kanyakumari
Dindigul
Thanjavur
Coimbatore
Dharmapuri
Dharmapuri
Erode
Krishnagiri
Coimbatore
Tiruvallur
Pudukottai
Tiruvallur
Tiruvallur
Tirunelveli
Virudhunagar
Namakkal
Tirunelveli
Kanchipuram Jinyang
Thoothukudi
Ariyalur
Virudhunagar
Chennai
Villupuram
Pudukottai
Trichy
Tiruvallur
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Nilgiri
Madurai
Jinyang
Jinyang
Ramanathapuram Jinyang
Vellore Jinyang
Salem
Perambalur
Cuddalore
Vellore
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang
Jinyang

Annexure II
Warning Bulletins issued by IMD
(i) Deep Depression Over Bay of Bengal (8 th to 10 th November), 2015
(a) Bulletins issued by Cyclone Warning Division, New Delhi
S.No. Bulletin
1
2
3
4
5
6
National
Bulletin
RSMC Bulletin
Press Release
DGM’s
Bulletin
SMS
CAP feed for
Google Public
Alert
No. of
Bulletins
10
18
3
3
4 times
Total SMS 244
4 times
Total SMS
1655/262501
21795- by
AFMU Karaikal
&
53330 by
AFMU Ooty
1
Issued to
1. IM D’s website
2. FAX and email to Control Room NDM, PMO- Minister of
Sc. & Tech, Cabinet Secretariat, Secretary MoES, DST,
HQ Integrated Defence Staff, Doordarshan, All India Radio,
National Disaster Response Force, Indian Railways, Indian
Navy, IAF, Chief Secretary- Andhra Pradesh, Tamil Nadu
Kerala, Karnataka.
1.
IMD’s website
2. All WMO/ESCAP member countries through
GTS and E-mail.
3. Indian Navy, IAF, by E-mail
1. IMD’s website
2. Emails to : press and electronic media
FAX and E Mail to
Cabinet Secretary, Principal Secretary to PM,
P.S. to Hon’ble Minister for S &T and MoES,
Secretary
Ministry of Home Affairs,
Ministry of Defence,
Ministry of Agriculture,
Ministry of I & B,
MoES, DST,
Ministry of Shipping & Surface Transport,
Director General, Shipping,
Central Relief Commissioner,
Ministry of Home Affairs Control Room, NDM,
Ministry of Home Affairs,
Director Of Punctuality,
Indian Railways,
Director Central Water Commission,
Director General, Doordarshan, AIR
1. Disaster management officers at central & State
Level (Andhra Pradesh, Tamil Nadu &
Puducherry,Kerala and Karnataka,)
2. Registered general public of Andhra Pradesh, Tamil
Nadu & Puducherry,Kerala and Karnataka,
3. Farmers through Kisan portal
General public

(b) Bulletins issued by Area Cyclone Warning Centre, Chennai:
S.No. Type of Bulletins
1. Sea Area Bulletins
2. Coastal Weather Bulletins
3. Fishermen Warnings issued
4. Port Warnings
5. Heavy Rainfall Warning
6. Squall Wind Warning
7. State of sea forecast
8. Information and Warning issued to State Government and other Agencies
(c) Bulletins issued by Cyclone Warning Centre, Visakhapatnam
No. of Bulletins issued
6
6
12
4
12
12
12
12
S.No. Type of Bulletin Number
1.
2.
3.
4.
5.
6.
7.
Coastal Weather Bulletins
Fishermen Warnings issued
Port Warnings
Heavy Rainfall Warning
Gale /squall Wind Warning
Information & Warning issued to State Government and other
Agencies (Pre-cyclone watch, informatory message e)
SMS to disaster managers
(ii) Well marked low Over Bay of Bengal (12 h to 18 th November), 2015
(a) Bulletins issued by National Weather Forecasting Centre, New Delhi
No. of Bulletins issued
6
14
4
4
4
4
50
S.No. Type of Bulletin
1.
2.
All India Weather Bulletin
All India Weather warnings
No. of Bulletins issued
28
28
(b) Bulletins issued by Regional Weather Forecasting Centre, Chennai
S.No. Type of Bulletin
1. Regional Weather Bulletin
No. of Bulletins issued
14
(c) Bulletins issued by State Weather Forecasting Centre, Hyderabad
S.No. Type of Bulletin
1. State Weather Bulletin
No. of Bulletins issued
14

(iii) Low Over Bay of Bengal (28 th Nov to 03 rd December), 2015
(a) Bulletins issued by National Weather Forecasting Centre, New Delhi
S.No. Type of Bulletin
1.
2.
All India Weather Bulletin
All India Weather warnings
No. of Bulletins issued
24
24
(b) Bulletins issued by Regional Weather Forecasting Centre, Chennai
S.No. Type of Bulletin
1. Regional Weather Bulletin
No. of Bulletins issued
12
(c) Bulletins issued by State Weather Forecasting Centre, Hyderabad
S.No. Type of Bulletin
1. State Weather Bulletin
No. of Bulletins issued
12

IMD issued early warnings for heavy rainfall in Tamil Nadu during the months of November and December which are summarized as under:
Spells of
Heavy rainfall commencing from
09-11-2015
16-11-2015
Date of Warnings issued
05 Nov. Heavy to very heavy rain at isolated places
06 Nov. Heavy to very heavy rain at isolated places
07 Nov. Heavy to very heavy rain at a few places with isolated extremely heavy
08 Nov. Heavy to very heavy rain at a few places with
isolated extremely heavy
13 Nov. Heavy to very heavy rain at a few places with isolated extremely heavy
14 Nov. Heavy to very heavy rain at a few places with isolated extremely heavy
15 Nov. Heavy to very heavy rain at a few places with isolated extremely heavy
21-11-2015
18 Nov. Heavy rain at isolated places
19 Nov. Heavy rain at isolated places
20 Nov. Heavy rain at isolated places
25 Nov. Heavy to very heavy rain at isolated places
26 Nov. Heavy to very heavy rain at isolated places
27 Nov. Heavy to very heavy rain at isolated places
30-11-2015
28 Nov. Heavy to very heavy rain at isolated places
29, 30 Nov & 1 Dec. Heavy to very heavy rain at a few places with isolated extremely heavy rainfall
2 02 Dec. Heavy to very heavy rain at a few places with isolated extremely heavy rainfall
02 03 Dec. Heavy to very heavy rain at a few places with isolated extremely heavy rainfall

03 Nov 2015 Isol H -TN
04 Nov 2015 Nil
Annexure IV :
Verification of heavy rainfall warnings issued by IMD
Date of
Issue
Day-1
Forecast
01 Nov 2015 Isol H-CTN
02 Nov 2015 Isol H-TN
Day-2
Actual
Isol H to VH Nil
Forecast
Isol H Isol H -TN
Isol H
Isol H to VH
Nil
Nil
Isol H to VH-
CTN
Isol H -TN
Actual
Isol H
Isol H
Isol H to VH
Nil
Day-3
Forecast
Nil
Nil
Nil
Nil
Actual
Isol H
Isol H to
VH
Nil
Isol H to
VH- CTN
Isol H 05 Nov 2015 Isol H-TN
06 Nov 2015 Nil
07 Nov 2015 Isol H to VH-TN
Nil
Isol H
Isol H -TN
Sct H to VH with Isol XH
Isol H to VH-
CTN
Isol H
Sct H to VH -
CTN
Isol H- INTTN
Isol H -TN
Isol H -TN
Sct H to VH with isol XH
Sct H to VH &
Isol XH- C TN
Isol H to VH
INTTN
Isol H
Isol H to VH-N
TN
Nil
Sct H to VH
– CTN, Isol
H- INTTN
Sct H to
VH & Isol
XH- CTN
Isol H to
VH-
INTTN
Isol H 08 Nov 2015 Sct H to VH with isol XH- NCTN
Isol H- rest TN
09 Nov 2015 Sct H to VH with isol XH- North TN
&PDC
Isol H-VH- S TN
10 Nov 2015 Isol H to VH- N TN
& PDC
Sct H to VH -
CTN
Isol H-
INTTN
Sct H to VH
& Isol XH- C
TN, Isol H to
VH- INTTN
Isol H
Sct H to VH with isol XH-
NTN, Isol H-
South TN
Isol H -TN
Nil
Isol H
Isol H Nil Sct H to VH
& Isol XH-
CTN, Isol H
- INTTN
Isol H 11 Nov 2015 Nil Isol H
12 Nov 2015 Nil Sct H to VH
& Isol XH- C
TN, Isol H -
INTTN
13 Nov 2015 Isol H –TN &PDC Isol H
Nil
14 Nov 2015 Isol H –Coastal TN Isol H to VH Isol H to VH-C
TN
Isol H – INTTN
15 Nov 2015 Sct H to VH with isol XH- North TN
&PDC
Sct H to VH
& Isol XH- C
TN, Isol H -
Nil
Isol H –TN
&PDC
Sct H to VH with isol XH-
North TN
Sct H to VH &
Isol XH- C TN
Isol H - INTTN
Isol H
Nil
Isol H –TN
&PDC
Isol H to
VH
Isol H to VH
Sct H to VH &
Isol XH- C TN
Isol H - INTTN
Isol H
Sct H to VH-
TN & PDC
Sct H to VH with isol XH-
North TN &
PDC
Isol H-VH- STN
Isol H to VH- N
TN
Sct H to
VH & Isol
XH- C TN
Isol H -
INTTN
Isol H
Isol H

Isol H-VH- S TN INTTN &PDC
Isol H - S TN
Nil 16 Nov 2015 Isol H to VH- N TN Isol H
17 Nov 2015 Nil Isol H Nil
Isol H
Isol H to VH
Nil
Nil
Isol H to
VH
Isol H to
VH
Isol H 18 Nov 2015 Isol H-TN & PDC Isol H to VH Isol H-TN &
PDC
19 Nov 2015 Isol H-TN & PDC Isol H to VH Nil
Isol H to VH
20 Nov 2015 Nil
21 Nov 2015 Isol H-TN & PDC
22 Nov 2015 Isol H to VH –S C
TN, Isol H –Rest
TN
23 Nov 2015 Isol H-TN&PDC
Isol H
Isol H
Isol H-C TN &
PDC
Isol H to VH-
TN & PDC
Isol H to VH Isol H –Coastal
TN
Isol H to VH Isol H-TN &
PDC
Isol H Nil 24 Nov 2015 Isol H- S C
TN&PDC
25 Nov 2015 Nil Isol H - C TN Nil
Isol H
Isol H
Isol H to VH
Isol H to VH
Isol H
Isol H - C TN
Isol H-C TN &
PDC
Isol H-C TN &
PDC
Isol H to VH-
TN & PDC
Nil
Nil
Nil
Isol H
Isol H to
VH
Isol H to
VH
Isol H
Isol H - C
TN
Nil
26 Nov 2015 Nil
27 Nov 2015 Nil
28 Nov 2015 Nil
Nil
Nil
Nil
Nil
Isol H- C
TN&PDC
Isol H to VH-
CTN & PDC
Nil
Nil
Nil
Isol H
Isol H- C
TN&PDC
Isol H- C
TN&PDC
Isol H to VH-C
TN & PDC
Isol H to VH-
CTN & PDC
Isol H – INTTN
Nil
Nil
Isol H
Isol H to
VH
29 Nov 2015 Nil
30 Nov 2015 Isol H to VH-C TN
& PDC
Isol H
Isol H to VH
Isol H -C TN &
PDC
Isol H to VH-
CTN & PDC
Isol H to VH
Sct H to VH &
Isol XH- C TN,
Isol H - INTTN
Isol H to VH-
CTN & PDC,
Isol H – INTTN
Isol H to VH-
CTN & PDC
Isol H-VH TN Sct H with Isol
VH-TN&PDC
Sct H to VH
& Isol XH-
C TN
Isol H-VH
TN
01 Dec 2015 Sct H with Isol
VH-TN&PDC
02 Dec 2015 Sct H-VH with Isol
XH- C TN
Isol H- INTTN
Sct H to VH
& Isol XH- C
TN, Isol H -
INTTN
Isol H-VH
TN
Sct H with Isol
VH-TN&PDC
Isol H to VH-
TN&PDC
Isol H Isol H to VH-
TN&PDC
Isol H
03 Dec 2015 Sct H with Isol VH-
CTN&PDC
Isol H Sct H & Isol
VH-CTN&PDC
Isol H-VH C
TN&PDC, Isol
Isol H- INTTN Isol H- INTTN H- INTTN
XH: Extremely Heavy Rainfall (25cm or more), VH: Very Heavy Rainfall (13 -24 cm),
H: Heavy Rainfall (7-12 cm) in 24 hours
TN: Tamil Nadu & Pudducherry, CTN: coastal Tamil Nadu, NTN: North Tamil Nadu,
STN: South Tamil Nadu, INTTN: Interior Tamil Nadu
Isol: Isolated (at one or two places: 1-25 % stations reporting rainfall),
Sct: Scattered (at a few places: 26-50% of stations reporting rainfall)
Correctly predicted scattered heavy to very heavy rainfall with isolated extremely heavy rainfall are highlighted.