Report on Cyclone 'Roanu'

Report on Cyclone ‘Roanu’

Track of Cyclone Roanu BMD Headquarters

Radar image of Cyclone Roanu Damage for Cyclone Roanu

Prepared by Shamsuddin Ahmed 1 , Mossammat Ayesha Khatun 2 , Md. Momenul Islam 3 , Md. Abdul Mannan 3 , S M Quamrul Hassan 3 , Md. Rashaduzzaman 3 , Md. Abdur Rahman Khan 3 , Md. Rubyet Kabir 3 , Md. Bazlur Rashid 3 , Kh. Hafizur Rahman 3 , A. K. M Ruhul Kuddus 3 , Muhammad Abul Kalam Mallik 3 , Md. Omar Faruq 3 , Md. Arif Hossain 3 , N i jhum Rokeya Ahmed 3 1 Director, Bangladesh Meteorological Dep artment , 2 Deputy Director, Bangladesh Meteorological Departmen t, 3 Meteorologist, Bangladesh Meteorological Department

Bangladesh Meteorological Department (BMD), Agargaon, Dhaka - 1207 Web: www.bmd.gov.bd

Preface Cyclones are among the most devastating weather systems on the Earth. They are large scale air mass es that rotate around a strong low pressure system . They are usually characterized by inward spiraling winds that rotate counterclockwise in the Northern Hemisphere. Cyclones are usually associate d with strong winds and rain, high ocean waves and storm surge. Pre - monsoon (March - May) and post - monsoon (October - November) are the two primary seasons for formation of Cyclone in the Bay of Bengal. Coastal regions of Bangladesh are very much vulnerable to damage from a Cyclone . Cyclone ‘ Roanu ’ was the first tropical storm of the season of 2016 in the Bay of Bengal. It developed as a low pressure area over Southwest Bay and adjoining areas off Sri Lanka at 0300 UTC of 15 May 2016. It concentrated in to a De pression and then Deep Depression on 17 May 2016. It intensified into a Cyclonic Storm (CS) ‘Roanu’ over West - Central Bay and adjoining SW Bay on 19 May 2016 . It moved north - northeastwards first and then northeastwards over North Bay and finally crossed Ba risal - Chittagong coast near Chittagong during 0600 to 1100 UTC of 21 May 2016. T he position and intensification of Cyclone ‘ Roanu ’ was monitored by Bangladesh Meteorological Department (BMD) from its formation to landfall and issued through 20 Special Wea ther Bulletins containing advisories for the stakeholders and end users including fishermen and others. Port Authorities and the Coastal District Administrations of Bangladesh were also advised in time to take proper preparation through hoisting signals fo llowing the Standing Orders on Disaster (SOD). Accordingly, causalities and the loss of lives and properties w ere in minimum level. I like to give my sincere thanks to the Ministry of Disaster Management and Relief (MoDMR) and Department of Disaster Manage me n t (DDM) for taking timely initiative as per the guidance of BMD for reducing the causalities and loss of lives of the vulnerable areas. My heartfelt thanks are due to the Meteorologists and Meteorological Technicians of Storm Warning Centre (SWC), BMD f or their constant effort to release the Special Weather Bulletins for Cyclone ‘ Roanu ’ in time and preparation of this report.

Shamsuddin Ahmed Director

Contents

Sl Topics Page 1 . Introduction 1 2 . Bri e f l ife hi s t o r y of Cyclone Roanu 2 3 . Monito ring and Prediction of Cyclone Roanu 4 3.1 M onit o ring Cyclone Roanu 4 3.2 Ge ne s i s of Cyclone Roanu 7 3.3 Inten s ifi c a tion a n d M o v e m e nt of Cyclone Roanu 7 3.4 Movement of Cyclone Roanu 7 Ma x imum Sust a i ned Surfa c e Wind s p ee d a nd es tim a t e d c e n t r a l 3.5 8 pr e s s ur e 3.6 S truct u re of cyclone Roanu 9 4 . Clim a t o logi ca l as p e c ts of cyclone formed over the Bay of Bengal 9 5 . F e a t u r e s cyclone Roanu o b se r v e d thr o ugh s a tel l ite a n d Radar 10 5.1 IN S A T - 3 D fe a t u r e s 10 5.2 M i c r o w a v e fe a t u r e s 1 2 5.3 F ea t u r e s ob se r v e d thr o ugh BMD R a dar 13 6. D y na m i ca l fe a t u r e s 15 7. Bul l e tins i ss ued b y BMD 2 3 8. Dam a ge due to Cyclone Roanu 2 6 9. Tr a c k p r e di c ti o n b y N W P mode l s 3 0 10. Rainfall p r e di c ti o n b y N W P mode l s 3 7 11. He av y r a infa l l prediction b y H W RF model 4 1 12. St o rm S urge prediction 4 2 13. A d v e r s e w ea t he r for ec a s t v e rifi ca tion 4 4 14. Su m m a r y a nd C o nc l us i o n 4 6 15. A ck n o w l e d g e m e n ts 4 6

1 . Introduction Tropical Cyclones (TCs) are among the most devastating weather systems on the Earth. They ca use considerable damage and destruction to lives and property due to strong gale winds, torrential rain and associated storm surge. Though general movement of the TCs is well known, it is desirable to have timely and reasonably accurate prediction of the t racks and intensities of such cyclones for effective implementation of the disaster mitigation. To improve the prediction, there is need of basic understanding of physics and dynamics involved in the genesis, intensity change, structure and track of tropic al cyclone. The concept of Conditional Instability of Second Kind (Charney and Eliassen , 1964 ) indicated that cyclonic inflow in lower tropospheric boundary layer is essential for develop - ment of TCs. Gray (1968) indicated that developing and non - developi ng cyclones are associated with different upper tropospheric circulation patterns e.g. non - developing TCs have uni - directional upper tropospheric flow which causes vertical shear above the cloud clusters relatively strong and the developing TCs normally ha ve multidirectional out flow that results in weak vertical shear above the cyclones. The study of Holland and Merrill (1984) concluded that not only upper tropospheric interactions but also the inner core convective heating may directly affect intensity c hange while lower tropospheric interactions will produce a size change which may indirectly affect the intensity or strength of Tropical cyclone. Craig and Gray (1996) showed that the intensification of numerically simulated tropical cyclones is due to Win d Induced Surface Heat Exchange (WISHE). Holland (1983) demonstrated that nonlinear combination of two processes: (i ) an interaction between the cyclone and its basic current (steering current) and (ii ) an interaction with the Earth’s vorticity field, is responsible for movement of TCs. The Cyclone Roanu was mainly detected and tracked by synoptic observation in addition to numerical model products and satellite imageries. Radar imageries from IMD network are also taken into consideration through internet . BMD also utilized the Dvorak technique of subjective assessment based on satellite (Dvorak, 1975, 1984) and environmental conditions for estimating the intensity. Higher sea surface temperatures (SSTs) (more than 26.5°C), a deep lower lev el moist layer, absence of strong vertical wind shear, increase in vorticity over the area, are favourable criteria for intensification of a tropical low to a cyclonic storm and further intensification (Gr ay, 1992 and Frank, 1977). The satellite base d monitoring and prediction of intensification were reviewed by Kelkar (1997) and further updated by Kalsi (2006) and Bhatia et al., (2006). According to them, new developments like derivation of cyclone parameters in terms of ocean surface wind fields by scatterometer more frequently and rapid scan observations by the satellites, use of water vapour imagery with better resolutions and other derived products like Outgoing Long wave Radiation (OLR) can immensely help in not only monitoring and p rediction of intensity but also in improving the Numerical Weather Prediction (NWP) model performance. According to Shea (2009), the depth of thermocline layer and hence the ocean thermal energy play a dominant role for intensification. Accordin g to him, ocean thermal energy of more than 100 KJ in the thermocline layer is favourable for intensification into a very severe cyclonic storm. The detailed review of the synoptic and thermodynamic characteristics associated with t he intensification/ decay of the cyclonic storm over the north Indian Ocean are presented by Krishna Rao (1997). The review of the dynamical characteristics of intensification is given by Mohanty and Gupta (1997). A review of the prediction of tropical cyclone characteristics by NWP models is presented by Prasad (1997) and has been updated by Rama Rao et. al (2007). However, the intensity change at present is not properly ca ptured in the NWP models (Rama Rao, et al ., 2007). The gen esis and movement of the cyclone ‘Roanu‘ though could be predicted by various NWP models, with reasonable accuracy, the intensity of the system remained unpredicted by most of the models. It posed a challenge to the NWP modelling as well as other conventional, synoptic and statistical methods to predict the intensity accordingly.

Considering all the above, an in - depth study has been undertaken to analyze various features of the cyclonic storm ‘Roanu’ like genesis, intensification, movement, landfall and associated disastrous weather. The monitoring and prediction aspects of this cyclone by the synoptic and thermodynamic observations, satellite observations, dynamical parameters and numerical weather prediction models and their limitations have been critically examined and discussed. The critical grey areas requiring more research and investigation have been highlighted. A brief life history of cyclone Roanu is presented in section 2 . Monitoring and prediction of cyclone Roanu is descrived in chapter 3. Climatological aspects, features observed through Satellite and Radar, dynamic features, storm surge prediction and damages due to the CS ‘Roanu’ are presented in the following section s. Summary and conclusion is given in section 14. 2. Brief history of Cyclone Roanu A low pressure area developed over Southwest Bay and adjoining areas off Sri Lanka at 0300 UTC of 15 May 2016. It intensified in to a Well Marked Low over the same area a t 0900 UTC of the same day. The system then moved north - northwestward and concentrated in to a Depression (Lat 11.0°N, Lon 81.0°E) over Southwest Bay and adjoining areas at 0600 UTC of 17 May 2016. The system then moved northward and intensified into Deep Depression over West - Central Bay and adjoining Southwest Bay (Lat 13.5°N, lon 81.0°E) 1200 UTC of 17 May 2016. It then moved north - northeastward further and intensified into a Cyclonic Storm (CS) ‘Roanu’ over West - Central Bay and adjoining SW Bay (Lat 15.0 °N, lon 81.2°E). In continuation to this, cyclone ‘Roanu’ moved north - northeastwards first and then northeastwards over North Bay and finally crossed Barisal - Chittagong coast near Chittagong during 0600 to 1100 UTC of 21 May 2016. Continuing its east - nor theastward journey, the CS gradually weakened into a DD over Mizoram at 1800 UTC of 21 May as a depression over Myanmar and adjoining Manipur at 0000 UTC of 22 May and into a well marked low pressure area over Myanmar and adjoining Nagaland & Ma nipur at 0300 UTC of 22 May. The observed track of the CS Roanu is shown in Fig.1.

Fig. 1: Observed track of the C yclone Roanu

The salient features of the system are as follows (Reference: Preliminary report of Cyclone Roanu by Cyclone Warning Div ision, India Meteorological Department, Ind ia ) . i. C yclone Ro a n u f o l l o w e d a un i q u e track, mo v ing v er y close to Sri L an ka a n d ea st c oa st o f I nd i a . It rec u r v e d no r t hea s t w a rds an d c r o ss e d B an g la d e sh c oa st to t h e no rth o f C h it t a g on g . ii. Lo w e st e stimat e d c e n t ral p re s s u re (ECP) w a s 9 8 3 h P a w ith a p re s s u re d rop o f 1 1 h P a . It tra v e l l e d a d is t an ce o f ab o u t 2 3 0 0 k m du r i n g its l i fe p e r i o d . iii. T h e Ac c u m u la t e d C y clo n e E ne r g y (ACE) w h ich is a m ea s u r e o f d a m a g e po t e n ti a l w a s a b ou t 1 . 8 4 2 X 10 k n ot . iv. T h e P o w e r D i ssip a ti o n I nde x w h ich is a mea s u re o f loss d u e to CS w a s 0 . 7 4 X 1 0 6 k n ot 3 . v. T h e l i f e pe r i o d o f Cyclone R oa n u w a s 5 da y s. vi. Cyclone Ro a n u s ho w e d la r g e sc a le d iur n a l v a r i a ti on s w .r.t. its c en tral c lo u d c o v e r an d s p i r a l b a nd s in t e r m s o f de p th o f clo u d an d a rea o f c o v e ra g e . W h i l e t h e clo u d ma ss in t en s i f i e d t o w a rds ea r l y mo rnin g , it s ho w e d si g n s o f w ea k en ing t o w a rds s un s e t . vii. Cyclone Ro a n u d id no t in t e n si f y to a s e v e re c y clo n e in s p ite o f its l o n g tra v e l o v e r t h e s e a ma inly du e to l a n d in te ra c ti on s an d a b o v e me n ti o n e d lar g e sc a le d iur n a l v a r i a ti on s viii. T h ou g h it d id no t c r o s s Sri Lan ka a n d I n d ia c oa sts, it c au s e d a d v e rse w ea t he r l i ke hea v y rain an d st r on g w ind a ll a lo n g e a st c oa st o f Sri Lan k a an d I nd i a . I t w a s ma inly du e to t h e f a ct t h a t t h e Cyclone R o an u mo v e d v e ry close to t h e e a st c oa st o f I nd ia a n d S ri Lan k a . ix. Cyclone R o an u lay c en t e red a b ou t 5 0 km ea s t - s ou t h ea st o f C he nn a i a t 03 0 0 U T C o f 18 , 6 8 km e a s t - s ou t h ea st o f M a c h i l l i pa t n a m a t 0 60 0 U T C o f 1 9 , 3 5 km s ou t h ea st o f K a l i n g a p a t na m a t 0 60 0 U T C o f 2 0,

4 0 k m s o u t h e a st o f P a ra d ip a t 1 20 0 U T C o f 2 0 a n d 7 0 km s ou t h - s ou t h ea st o f S a g a r Isl a n d a t 0 00 0 U T C o f 2 1 M a y . x. IMD p re d ict e d g ene sis o f dep r e ssion o v e r s o u t h w e st B o B o n 1 7 M a y ba s e d o n 03 0 0 U T C ob s e r v a ti on s

o f 1 4 M a y (a b ou t 7 2 hou rs i n ad v an c e ). xi. T h e nea r l y no rt h - n o r t hea st w a rd a n d no r t h e a st w a rd mo v e m e n t o f t h e s y st e m an d la nd f a ll o v e r

B an g la de sh w a s p re d ict e d since t h e f o r m a t i o n o f d ee p dep ressi o n o n 1 8 Ma y m o rning ( mo re t h a n 7 2 h ou rs i n ad v an ce o f la n d f a l l ). xii. T h e n u me r i c a l w ea t h e r p re d iction ( N W P) an d d y n a m ical st a tistic a l m o de l s p ro v id e d re a s o n ab le g u id an c e w ith res pe ct to its g ene si s , track a n d in ten sity o f t h e s y st em . xiii. Fi r st in f o r ma t o ry me ss a g e w a s issu e d o n 1 3 M a y w ith f o rec a st o f a ss o cia te d w ea t he r incl ud ing h e a vy rain f a l l , g a le w i n d w a rnin g s f o r T a m il Na d u & P udu c he r r y an d K e r a la c oa sts f o r n e x t 4 8 hou rs. No l a n d f a ll f o rec a st w a s issu e d f o r an y st a t e i n ea s t c oa s t o f I n d ia. Ho w e v e r, t h e w a rning a g a inst t h e hea v y rain fa ll an d s q ua l l y / g a le w i nd s a lo n g t h e c oa sts o f A n dh ra Pra de s h , O d isha a n d W e st B e n g a l w e re issu e d re g u lar l y to t h e c o n c e r n e d d i s a s t e r ma n a g e rs, me d ia a n d g ene ral p u b l i c e tc. xiv. Every three hourly TC Advisories were issued to WMO/ ESCAP Member Countries including Sri Lanka and Bangladesh.

3 . Monitoring and Prediction of Cyclone Roanu 3.1 M onit o ring Cyclone Roanu Cy clo n e ‘Roanu’ was mon i t o red and p re d ict e d c o n ti nu o u sly since its inc e p ti o n b y BMD. T h e o b s e r v e d t ra ck o f t h e c y clo n e o v e r the Bay of Bengal ( B o B ) du r i n g 1 7 - 22 M a y 2016 is depicted in Fi g . 1 . T h e b e st track p a rame te rs o f t h e s y st e m s a re given in Ta b le 1 . At t h e g ene sis s t a g e , t h e s y st e m w a s m o n it o red m a i n ly w ith s a t e l l ite ob s e r v a ti on facilities of BMD (Himawari and FY - 2D, FY - 2E FY - 2G) . V a r i ou s n a ti o na l a n d international N W P mo d e ls i n clu d ing the products of IMD a n d N CM R W F were u til i z e d to p re d ict t h e g e n e sis, track an d i n t en sity o f t h e c y clo ne . Table 1: Position and Status of Cyclone Roanu as per BMD Record Estimated Centre Time ECP Sustained Status/ Sl Date Location Lat. °N/ Local (UTC) (hPa) Surface Grade Lon. °E Wind (kt) SW Bay and 01. 15.05.2016 09 AM (0300) - - - L adjoining area SW Bay and 02. 15.05.2016 03 PM (0900) - - - WML adjoining Si Lanka SW Bay and 11.0°N/ 03. 17.05.2016 12 Noon (0600) - 40 - 50 kph D adjoining area 81.0°E Midnight SW Bay and 11.5°N/ 04. 17.05.2016 - 4 0 - 50 kph D (1800 ) adjoining area 81.0°E SW Bay and 13.0°N/ 05. 18.05.2016 12 Noon (0600) - 40 - 50 kph D adjoining WC Bay 80.8°E WC Bay and 13.5°N/ 06. 18.05.2016 06 PM (1200) - 50 - 60 kph DD adjoining SW Bay 81.0°E Midnight WC Bay and 13.9°N/ 07. 18.05.2016 - 50 - 60 kph DD (1800) adjoining SW Bay 81.0°E WC Bay and 14.3°N/ 08. 19.05.2016 03 AM (2100) - 50 - 60 kph DD adjoining SW Bay 81.1°E WC Bay and 15.0°N/ 09. 19.05.2016 09 AM (0300) 992 hPa 62 - 88 kph CS adjoining SW Bay 81.2°E WC Bay and 15.5°N/ 10. 19.05.2016 12 Noon (0600) 992 hPa 62 - 88 kph CS adjoining SW Bay 81.5°E WC Bay and 15.5°N/ 11. 19.05.2016 06 PM (1200) 992 hPa 62 - 88 kph CS adjoining SW Bay 81.5°E Midnight WC Bay and 16.0°N/ 12. 19.05.2016 992 hPa 62 - 88 kph CS (1800) adjoining area 81.9°E WC Bay and 16.4°N/ 13. 20.05.2016 06 AM ( 0000) 992 hPa 62 - 88 kph CS adjoining area 82.6°E WC Bay and 18.0°N/ 14. 20.05.2016 12 Noon (0600) 992 hPa 62 - 88 kph CS adjoining area 84.2°E North Bay and 18.5°N/ 15. 20.05.2016 06 PM (1200) 992 hPa 62 - 88 kph CS adjoining WC Bay 85.0°E North Bay and 19.5°N/ 16. 20.05.2016 09 PM (1500) 992 hPa 62 - 88 kph CS adjoining WC Bay 86.6°E Northwest Bay and Midnight 20.6°N/ 17. 20.05.2016 adjoining 992 hPa 62 - 88 kph CS (1800) 87.7°E Bangladesh coast Northwest Bay and 20.6°N/ 18. 20.05.2016 03AM (2100) 992 hPa 62 - 88 kph CS adjoining 88.7°E

Estimated Centre Time ECP Sustained Status/ Sl Date Location Lat. °N/ Local (UTC) (hPa) Surface Grade Lon. °E Wind (kt) Bangladesh coast Northwest Bay and 06:00 AM 20.8°N/ 19. 20.05.2016 adjoining 992 hPa 62 - 88 kph CS (0000) 90.0°E Bangladesh coast Northwest Bay and 21 .5°N/ 20. 20.05.2016 09 AM (0300) adjoining 992 hPa 62 - 88 kph CS 90.7°E Bangladesh coast Started to cross Barisal - Chittagong 22.0°N/ 21. 20.05.2016 12 Noon (0600) 992 hPa 62 - 88 kph CS coast near 91.0°E Chittagong Crossed Barisal - 22. 20.05.2016 06 PM (1200) Chittagong coast - 62 - 88 kph C S near Chittagong

Note: ‘L’ indicates Low; ‘WML’ indicates Well Marked Low; ‘D’ indicates Depression; ‘DD’ indicates Deep Depression; ‘CS’ indicates Cyclonic Storm

18 May 2016: 0740 UTC 18 May 2016: 1333 UTC

19 May 2016: 0719 UTC 19 May 2016: 1317 UTC

20 May 2016: 0748 UTC 20 May 2016: 1932 UTC

21 May 2016: 1320 UTC 21 May 2016: 1914 UTC

22 May 2016: 0116 UTC 22 May 2016: 0505 UTC

Fig. 2: To t a l p r ec ipit a b le w a t e r i m a g e ri e s d u ring 17 to 2 2 M a y 20 1 6 (Source: IMD)

3 . 2 G e ne s i s of Cyclone Roanu A tro u g h o f low l a id o v e r s ou t h w e st B a y o f B en g a l (B o B) w ith its u p pe r a ir c y clo n ic ci r c u la t ion e xt end i n g

up to 4 .5 km a bo v e me a n s e a le v e l a t 0 3 0 0 U T C o f 14 M a y 2016 . Un de r this condition , a low p ress u re a r e a d e v e lo pe d o v e r S o u t h w e st B a y o f B en g a l o ff Sri L an ka c oa s t in t h e morning of 15 Ma y 2016 . It then moved no rt h - no rth e a st wards, intensified into a W e ll Marked L o w P ress u re A rea a t 0 9 0 0 U T C o f same day o v e r s ou t h w e st B o B a n d ad joi n ing Sri Lan k a . It f u rth e r mo v e d sl ig h tly no rth w e st w a rds an d l a y o v e r Sri Lan ka a n d ad joi n ing a r e a s o f G u l f o f M a n na r & S ou t h w e st B o B a t 03 0 0 U T C o f 1 6 May . At 0 3 0 0 U T C o f 17 May , t h e s e a s u r f a c e t e m pe ra t u re w a s 3 0 - 3 1 ˚C, Oc ea n t he r ma l e ne r g y w a s 100 - 2 - 5 - 1 - 5 - 1 120 K J/c m , low le v e l c on v e r g en ce w a s (2 0 - 30 ) x 1 0 S , up p e r l e v e l d i v e r g en ce w a s ab o u t (2 0 - 3 0 ) x 1 0 S , - 6 - 1 t h e low le v e l re la t i v e v o rtic i t y w a s abou t (1 00 - 1 5 0 ) x 10 S , v e rtical w i n d s h e a r o f ho r i z on t a l w ind w a s mode r a te (1 0 - 2 0 k no ts). U pp e r tro po s p he r i c r i d g e lay a lo n g 1 5 . 0 ° N. C on s i de r i n g lar g e sc a le f ea t u res, Ma dd e n J u l ia n Oscil l a ti o n w a s a lso f a v ou ra b le an d lay in P ha s e - 3 w ith a mp l i t ud e > 1 . U n de r t he s e f a v ou ra b le c ond iti o n s, t h e s y st e m m o v e d no rt h - n o rth w e st w a rds, c on c e n tra t e d in t o a Depression (D) an d l a y c en t e red a t 0 6 0 0 UTC o f 1 7 May o v e r s o u t h w e st B o B n ea r la t i t u d e 11 . 0 ° N an d lo n g it u d e 8 1 . 0 ° E. 3.3 Inten s ifi c a tion a n d M o v e m e nt of Cyclone Roanu At 1200 U T C o f 1 8 May 2016 , t h e s e a s u r f a ce t em pe rat ur e w a s 31 ° C, Oc ea n t h e r m a l ene r g y w a s 15 0 K J / c m 2 , low le v e l c on v e r g en ce ( 3 0 x 1 0 - 5 S - 1 ) , u ppe r le v e l d i v e r g en ce ( 40 x 1 0 - 5 S - 1 ) an d low lev e l rela t i v e v o rtic i t y (1 5 0 - 2 0 0 x 1 0 - 6 S - 1 ) incre a s e d , f a v ou r i n g i n t en s i f i c a ti o n o f t h e s y st e m . U ppe r tro po s p he r ic r i d g e l aid a lo n g la t it u d e 16.0 ° N. M JO lay in pha s e - 4 w i th a mp l i t u d e > 1 . Un de r t h e i n f lu e n ce o f f a v ou ra b le e n v i r onme n t a l c ond it i on s t h e s y st e m m o v e d nea r l y no rt h w a rds an d in ten s i f i e d in t o a Deep Depression (DD) an d lay c en tred o v e r W e st - c en tral a n d a d jo i n ing S ou t h w e st B o B a t 1200 U T C o f 18 May n e a r la t i t ud e 1 3 . 0° N a n d l o n g it ud e 8 1 . 0 ° E. T h e f a v ou ra b l e en v i r onme n t a l c ond it i o n s c o n ti n u e d a n d a t 0 3 0 0 U T C o f 1 9 May , t h e u ppe r tro po s p h e r i c r i d g e s h i f t e d no rth w a r d s an d lay abo u t 1 7 . 0 ° N . The s y st e m mo v e d n o rt h - no rt h ea st w a rds, in ten s i f i e d in t o a Cyclonic Storm (CS) w ith m a x i mu m s u s t a in e d w i n d s o f 62 - 88 KPH a ro u n d t h e s y st e m c en tre a t 0 3 0 0 U T C o f 1 9 May . U n de r f a v or ab l e environmental c ond iti o n s t h e s y st e m ski r t e d a lo n g t h e ea s t c oa st o f I nd ia an d i n t en s i f i e d sl ig h tly w i th ma x i m u m s u s t a in e d w ind s p ee d of 6 2 - 88 KPH . The s y st e m ma in t a i n e d its in t e n sity an d cros s e d Chittagong - Barisal coast of B an g la d e sh near Chittagong a s a CS. Th e re a f t e r, t h e s y st e m s t a rt e d w ea k e n ing d u e t o l a n d i n t e racti o n s. Co n t i nu i n g its ea s t - no rth e a st w a rd jo u rn e y t h e s y st e m g ra dua l l y w ea k ene d in t o a DD o v e r M i z ora m a t 18 0 0 U T C o f 2 1 May in t o a d e p ressi o n o v e r M y anma r an d ad joi n ing M an i p u r a t 0 00 0 U T C o f 2 2 May an d in t o a W e ll Ma rk e d L o w P ress u re A rea o v e r M y anma r a n d a d joi n i n g N a g a la n d & M a n ip u r a t 0 30 0 U T C o f 2 2 M a y 2016 . The total precipitable water imageries (TPW) during 17 - 22 May are presented in Fig. 2. It indicates that due to cross equatorial flow warm and moist air continued to converge around the system centre till 19 May. On 20 May, it gradually decreased and it further decreased on 21 May a s the system moved to the northern latitude and crossed Bangladesh coast. 3.4 Movement of Cyclone Roanu C yclone Ro an u mo v e d n e a r l y no rth w a rds till m i dn i g h t o f 1 8 M a y . It t he n mo v e d no rt h - no rth e a st w a rds till m id n i g h t o f 1 9 May a n d t h e n no rth e a st/ e a s t - no rt h e a stwards during its remai n ing l i f e pe r i o d . Un de r t h e i n f l u e n ce o f a n tic y clo n ic ci r c u la t ion loc a t e d to t h e no rth e a st o f t h e s y st e m c e n tre, it mo v e d ini t ially no rt h - no rth w e stw a rds a n d t h e n it c a m e close to t h e r i d g e an d hen ce m o v e d no rth w a rds till m id n i g h t o f 1 8 May. Th e re a f te r, a s t h e s y st e m tra n siti o n e d to t h e no r t h o f t h e r i d g e , it mo v e d i n itially no rt h - no rt h ea st w a rd s . T h e re a f te r, o n 20 May , it c am e

u nde r t h e i n f l u e n ce o f tr o u g h in m id t r opo s phe r i c w e st e r l ies l y i n g to t h e w e st o f s y st e m c en tre w h ich he l p e d in no r t h e a s t / ea s t - n o rt h ea st w a rds mo v e m en t o f t h e s y st e m a n d a lso incre a s e in tra n sla t i o na l s p e e d o f t h e s y st em . The tra n sla t i o na l s pe e d g rad u a l l y incre a s e d f r o m a l mo s t z e ro a ro un d m id n i g h t o f 1 8 to 4 2 k m /hr b y e v en ing o f 2 0 M a y . T h e six hou r l y mo v emen t o f CS Ro a n u is p res en t e d in Fi g . 3 . T h e s y st e m h a d a t rack l e n g th o f a b ou t 23 00 km d u r i n g its l i f e pe r i o d .

Fig. 3 : S ix hourly a v e r a ge tra n s l a tional s p e e d (km /hr ) a nd d ir ec t ion of mo v e m e nt in ass o c i a tion w ith CS Roanu (Source: IMD)

T h e w ind s pe e d in m i dd le a n d d ee p la y e r a ro un d t h e s y st e m c e n t re in d ica t e s t h a t f r o m 1 8 May on w a r d s, t h e m id d le to u ppe r l ev e l st ee r i n g f low w a s s up p o rting t h e abo v e d i r e cti o n a n d s p e e d o f m o v em e n t. Un de r t h e in f l uen c e o f m i d d l e an d u p pe r t r opo s phe r i c tro u g h , t h e w ind s h e a r a ro u n d t h e s y st e m be t w ee n 850 and 20 0 h Pa le v e ls a lso incr e a s e d ra p i d ly o n 2 0 an d 2 1 May . As t h e w ind s h e a r w a s ea s t - s ou t h ea s t e r l y , t h e c o n v e ct i v e clo u d m a ss w a s s h e a red t o w a rds wes t - no rth w e st w a rds o f t h e s y st e m c e n tre till 2 0 May . T he r e a f t e r, w ith t h e c han g e in d i r e ct i o n o f w ind s hea r a s s ou t h / s o u t h w e st e r l y , t h e c on v e cti v e clo u d ma s s w a s s h ea r e d no rth / no r t hea s t w a rds s ou t h / s o u t h w e st e r l y , t h e c on v e cti v e clo u d ma s s w a s s h ea r e d no rth / no r t hea s t w a rds on the day of rainfall. 3.5 Ma x imum Sust a i ned Surfa c e Wind s p ee d a nd es tim a t e d c e n t r a l pr e s s ur e T h e lo w e st e sti ma t e d c en tral p ress u re (ECP) a n d t h e ma x i m u m s u s t a in e d w ind s pee d a re p res en t e d in Fi g . 4 . The lo w e st e sti m a t e d c en tral p ress u r e h a d be e n 98 3 h P a . The e sti m a t e d ma x i m u m s u st a i n e d s u r f a c e w ind s pee d ( M S W ) (defined as V max ) w a s 4 5 k no ts d u r i n g 180 0 U T C o f 2 0 May to 0 9 0 0 U T C o f 2 1 M a y . At t h e ti m e o f la nd f a l l , t h e E CP w a s 98 3 h Pa an d M S W w a s 4 5 k no ts (c y clo n ic st o r m ). T h e f i g u re a lso in d ica te s t ha t t h e s y st e m d id n o t in ten s i f y m u ch d e s p ite its l on g j o u rn e y o v e r s e a mai n ly be c au se o f i ts p ro x i m ity w i th l and . T h r o u g hou t its l i f e c y cle, t h e s y st e m ski r t e d a lo n g t h e e a st c oa st o f I nd ia an d lay a s clo s e a s 5 0 k m e a s t - s o u t h ea st o f Ch e nna i a t 0 30 0 U T C o f 1 8 May , 6 8 km e a s t - s ou t h e a st o f M a c h i l l i pa t n a m a t 0 60 0 U T C o f 1 9 May , 3 5 km s ou t h ea st o f K a l i n g a p a t n a m a t 0 60 0 U T C o f 20 May , 4 0 km s o u t h ea st o f P a ra d ip a t 1 2 0 0 U T C o f 2 0 May a n d 7 0 k m s ou t h - s ou t h e a st o f S a g a r Isl an d a t 00 0 0 U T C o f 2 1 May . T h e ECP an d V max g ra p h a lso in d ica t e s t h a t t h e s y st e m in ten s i f i e d g ra du a l l y till 180 0 U T C o f 2 0 May, ma in t a in e d its in ten sity till la nd f a ll a t 10 0 0 U T C o f 21 May an d w ea k ene d g ra d u a l l y in t o a w e ll ma rk e d low p ress u re a r e a a t 0 3 0 0 U T C o f 2 2 M a y . T he re w a s n o ra p id in t en s i f ica t i o n an d ra p id w ea k en ing o f t h e s y st e m t h ro u g h o u t it s l i f e c y cle.

Fig. 4 : L o w e s t e s ti m a ted ce n t r a l pr e ss ure a nd t h e m ax imum s u s tain e d w ind s pe e d (Source: IMD) 3.6 S truct u re of cyclone Roanu S e ct o r w ise w ind d istr i bu ti o n a r o un d t h e s y st e m c e n tre is depicted in Fi g . 5 . It dep icts t ha t the ma x i m u m w i nd s w e re ob s e r v e d in s ou t h ea st s e ct o r f o l l o w e d b y no rth ea st an d s o u t h w e st s e ct o r. T h e w ind d istr i bu t ion a lso s ho w e d d i u rn a l v a r i a ti on s l i ke c on v e cti on . M a x i m a in w ind d istr i bu ti o n a n d ra d ius o f ma x i m u m w ind ( R M W ) w e re ob s e r v e d n o r ma l l y a t 06 0 0 U T C a t a lag o f 6 h o u rs t o c o n v e cti o n m a x i ma . S i m i l a r l y m inima w a s ob s e r v e d a t 1 80 0 U T C a t a l a g o f ab o u t 6 h o u rs f r o m c o n v e cti o n m inima ob s e r v e d a t 1 2 0 0 U T C du r i n g 1 8 to 2 0 May 2016 .

Fig. 5 : S ec t o r w i s e w i n d di s tribu t ion of CS ‘ R oanu ’ (Source: IMD) 4 . Clim a t o logi ca l as p e c ts of cyclone formed over the Bay of Bengal Co n sid e r i n g t h e a r e a o f g e n e sis ( + / - 2 0° a r o u n d t h e g ene sis po in t ), t h e cl ia m t o lo g ical tracks o f t h e T Cs du r i n g 189 1 - 20 1 5 a r e p res e n t e d i n Fi g . 6 . It in d i c a t e s t ha t cl i mato lo g icall y , abo u t 50 % o f t h e t racks mo v e d n o rth w e st w a rds an d cross e d Ta m il N a d u c oa st w he re a s ano t h e r 5 0% mo v e d no rt h - no rt h ea st / no rt h ea st w a rds. O u t o f t h e 3 s y st em s rec u r v i n g nor t hea s t w a rds, 2 d iss i pa t e d o v e r t h e s e a an d on ly 1 c r o ss e d W e s t B en g a l c oa st d u r i n g Ma y 1936 . He n c e c o mp a r i n g t h e cl i ma t o lo g ic a l tracks, t h e track o f Ro an u w a s un i q u e in n a t u re mo v i n g v er y close to t h e c oa st a n d rec u r v ing no rth e a st w a rds t o w a rds B an g la d e sh c oa st.

Fi g. 6 : C l i ma t o lo g ical t racks o f T ropical Cyclones f o r m ing w it h in + / - 2° a ro un d t h e g e ne sis p o int du r i n g 18 9 1 - 20 1 5 (Source: IMD) 5 . F e a t u r e s of cyclone Roanu o b se r v e d thr o ugh s a tel l ite a n d Radar S a t e l l ite m on i t o r i n g o f t h e s y st e m w a s ma inly don e b y u sing ha l f h o u r l y K a lp an a - 1 an d IN S A T - 3 D i ma ge r i e s. S a t e l l ite i m a g e r i e s o f in te r n a ti o na l g eo st a ti o na ry s a t e l l it e s M e t eo s a t - 7 & M T SA T an d m ic r o w a v e & h i g h res o lu t ion i ma g e s o f p o lar o rbiting s a t e l l it e s D M SP, NOAA s e r i e s, T R MM , M e t o p s w e re a lso c on si d e re d . 5 .1 IN S A T - 3 D fe a t u r e s T y p ical INS A T - 3 D v is ib le / IR i ma g e r i e s (Fig. 7) , e n ha n c e d c o lo r e d i m a g e r i e s an d clo u d t o p b r ig h t ne ss t e m p e r a t u r e i ma g e r i e s a re p re s en t e d in Fi g . 8 . I n t en sity e sti ma ti o n u sing D v o rak’s t e c hn i q u e s u g ge st e d t ha t t h e s y st e m a t t a i n e d t h e in t en sity o f T 1 . 5 o n 0 30 0 U T C o f 17 May . T h e cl o u d pa t t e rn w a s c ur v e d ban d t y pe . Co n v e cti o n w r appe d 0 .2 o n l o g 1 0 s p i r a l. Ass o ci a t e d b ro k e n low an d m ed i u m c l oud s w ith e m b ed d e d i n t en s e t o v e ry in ten se c on v e cti o n lay o v e r no rth Sri Lan k a , T a m il Na du , C o mo r i n , P a lk Strait, G u l f o f M a n na r, s ou t h w e st B o B a n d t h e a r e a be t w ee n be t w ee n la t it u d e 9 . 0° N t o 1 6 . 0° N a n d w e st o f lo n g it ud e 8 5 . 0° E. L o west clo u d t o p t e m pe ra t u re ( C TT ) w a s - 93° C. At 03 0 0 U T C o f 1 8 May , t h e s y st e m a t t a in e d t h e in ten sity o f T 2 . 0 . T h e clo u d pa t t e rn w a s c en tral den s e o v e rcast ( CDO) t y pe . Ass o ci at e d bro k e n low an d me d ium c l oud s w ith e m b e d d e d in t en s e to v e ry in ten s e c o n v e cti o n l a y o v e r no rth T a m il Na du , A n dh ra Pra d e s h , s ou t h w e st B o B an d ad joi n ing West c en tral B o B b e t w ee n la t i t ud e 1 0 . 0° N to 1 8 . 0° N a n d w e st o f lo n g it ud e 85 . 5° E. Lo w e st clo u d t o p t e mpe r a t u re ( C T T ) w a s - 93° C. At 030 0 U T C o f 19 May , t h e s y st e m in ten s i f i e d to T 2 . 5 . As s o cia t e d b rok e n low an d m e d i u m clo ud s w ith em b e d de d i n t en s e t o v er y in ten se c on v e c t ion lay ove r no rth A ndh r a Pra de s h , a d joi n ing O d isha a n d W e stc en tral B o B b e t w ee n la t i t u d e 1 2 . 0 ° N t o 2 0 . 0 ° N a n d w e st o f lo n g it ud e 90 . 0 ° E. Lo w e st clo u d t o p t e m pe ra t u re ( C TT ) w a s - 93 ° C. At 12 0 0 U T C o f 1 9 May , t h e in ten sity w a s T 2 . 5 . Ass o cia t e d b r o k e n l o w an d m ed i u m cl o u d s w ith em b ed d e d i n t en se to v e ry in ten se c on v e cti o n lay o v e r A ndh ra Pra d e sh an d W es t - C e n tral B o B b e t w ee n la t i t u d e 1 3 . 5 ° N t o 19 . 0 ° N an d w e st o f l o n g it ud e 8 6 . 0 ° E. L o w e st clo u d t o p t e m p e ra t u re ( C T T ) w a s - 88 ° C. LL CC w a s loc a t e d o n t h e e a st si d e o f c o n v e cti on . T h e pa t t e rn w a s s hea r t y p e w ith c en t e r 1 /3 d e g in t o da rk g re y . C on v e cti o n a ss o ci a t e d w ith R oan u w ea k en e d c on si d e ra b ly du r i n g p re v io u s 6 h rs. Clo u d t o p t em p e ra t u r e s w a r me d n o t a b ly an d o r g an i z a ti o n d i m i n ish e d f r o m a c on s o l id a t e d m a ss n ea r t h e c en t e r t o b rok e n c on v e cti o n a l o n g t h e s o u t he rn b an d . At 03 0 0 U T C o f 2 0 May , in ten sity w a s T 2 . 5 . Ass o cia t e d b rok e n l o w an d med i u m clo u d s w ith emb e dd e d in t e n se to v e ry in ten se c on v e cti o n lay o v e r n o rth c o a st a l A n d h ra Pra de s h , O d i s ha , w e stc en tral a n d ad joi n ing no rth w e st B o B b e t w e e n la t i t ud e 1 4 . 0 ° N to 20 . 0 ° N an d w e st o f l o n g it ud e 9 0 . 0 ° E. L o w e st clo u d t o p t e m p e ra t u re ( C T T ) w a s - 93 ° C. Co n v e cti o n ra m p e d u p s u gg e sti n g d iurn a l v a r i a ti on s. At 1 2 0 0 U T C o f 2 0 May , in ten sity w a s T 2 . 5 .

17 May 2016: 0000 UTC 18 May 2016: 0300 UTC 18 May 2016: 1200 UTC

19 May 2016: 1200 UTC 20 May 2016: 0032 UTC 21 May 2016: 0000 UTC

21 May 2016: 0900 UTC 21 May 2016: 1800 UTC 22 May 20 16: 0300 UTC

Fig . 7 : IN S A T - 3 D e nhan ce d c olor e d i m a ge r i e s b a se d on d uring 17 - 2 2 M a y 201 6 (Source: IMD) Ass o cia t e d b ro k e n low an d med i u m clo ud s w ith emb e dd e d in ten s e to v er y in ten se c on v e cti o n lay o v e r n o rth c oa s t a l A ndh ra Pra de s h , O d ish a , no r t h w e st an d ad joi n ing w e stc en tral B o B o v e r t h e a rea n o rth o f la t i t ud e 1 5 . 5° N a n d w e st o f l o n g it ud e 9 0 . 0° E . Lo w e st clo u d t o p t em pe rat u r e ( C T T ) w a s - 90° C. T h e c on v e cti o n s h o w e d incre a se in o r g an iza t ion du r i n g p a st six h rs. It c on ti nu e d to e x h ibit la r g e sc a le d iurn a l v a r i a ti o n w i th res pe ct t o c e n tral d en se o v e rcast clo ud s a n d t h e c u r v e d ba n d s i n t en sity a n d si z e . At 03 0 0 U T C o f 2 1 May , t h e in t e n sity w a s T 3 . 0 . Ass o cia t e d b rok e n low a n d m e d ium clo u d s w ith embe d de d i n t e n s e to v e ry

11 in ten se c on v e cti o n lay o v e r G an g e t ic W e st B en g a l, no r t h & ad jo i n ing c en t r a l B o B, s ou t h B a n g la de s h , T r ip u ra, Ma n ip u r no r th o f la t it u d e 17 . 0° N. Lo w e st clo u d t o p te m p e rat u re ( C T T ) w a s - 93° C. At 1 0 0 0 U T C o f 2 1 May , t h e s y st e m cross e d B an g la de s h c o a st n e a r no rth o f Chit t a g on g . At 1 2 0 0 U T C o f 2 1 May , a ss o cia t e d b rok e n low an d m ed i u m clo u d s w i t h e m be d de d i n t en s e to v er y in ten se c o n v e cti o n lay o v e r no rth ea s t B o B, T r i pu ra, M an i p u r, M i z o ra m , s ou t h ea st B an g l a de sh a n d s o u th Ass a m . Lo w e st clo u d t o p t e m pe r a t u re ( C TT ) w a s - 93° C.

16 May (2309 UTC) 1 7 May ( 0902 UTC) 1 7 May (2 255 UTC)

1 8 May ( 1325 UTC) 1 8 May ( 2121 UTC) 1 9 May ( 0646 UTC)

1 9 May (2 005 UTC) 20 May ( 0111 UTC) 20 May ( 2214 UTC)

21 May ( 0135 UTC) 21 May ( 0801 UTC) 21 May (2 030 UTC)

Fig. 8 : T y pi ca l mi c r o w a v e i m a ge r i e s during 17 to 2 2 M a y 2016 (Source: IMD) 5 .2 M i c r o w a v e fe a t u r e s F - 1 5 , F - 1 6 , F - 17 a n d GC O M - W 1 m i c r o w a v e i m a g e r i es o f t he Cyclone R o a nu co v eri n g i t s li f e p e r i od fr o m 17 t o 22 M ay 2 0 16 are p r es e nted i n F i g . 8 . T h e se i m a g eri e s h el p ed i n u n d e r s t a n d i ng t he i nte r n a l s t r uct u r e o f

12 t he s y s t em a n d b e tt e r est i m ati o n o f l oc a t i on o f t he sy s t em. I t c o ul d i n di cate t he r e g i on o f i nt ense co n v ecti o n a n d h e nce t he r a i n f a ll . I t a l so h el p e d i n u n d e r s t a n d i n g t he l a r ge sca l e d i urnal v ari a t i on o f t he s y s t e m . 5 . 3 F ea t u r e s ob se r v e d thr o ugh BMD R a dar As t h e s y st e m w a s m o v ing a lo n g t h e ea st c o a st, it w a s track e d b y D W R C h en n a i, M a c h i l l i pa t n a m , V is h a k hap t an a m , P a ra d ip a n d K o lka t a o f I n d ia a n d D W R K he p upa ra & Co x ’s B a z a r o f B an g l a de s h . T y p ical Ra da r i ma g e r i e s f r o m D W R K he p upa ra du r i n g 2 0 - 21 M a y 2016 a re p res en t e d in Fi g . 10 . T y p ical i m a g e r i e s f r o m I n d ian r a da rs a re p res e n t e d in Fi g s . 9 - 11 .

F ig. 9 : Khepupara Radar imageries during 20 and 21 May 2016 in association with Cyclone Roanu

(a) (b) (c)

Fig. 1 0 : P l a n P o s it i on Indi ca t o r ( PPI ) ( d B Z) i m a ge r i e s from D W R V is h ak ha p a t n a m a t (a) 03 5 9 , (b) 0 64 9 a nd (c) 0 7 2 9 UTC of 2 0 May 2016 (Source: IMD)

(a) (b)

Fig. 11 : M a x (d B Z) i m a ge r i e s from D W R Vi s h a k hap a t n a m a t (a) 0 402 , (b) 05 0 2 , (c) 0 60 2 a nd (d) 0 6 0 8 UTC of 2 0 M a y 2016 (Source: IMD)

6 . D y na m i ca l fe a t u r e s Dynamic features associated with cyclone Roanu are given in Figs. 12 - 19.

F i g. 1 2 : Pres sure Field (03 hourly) associated with cyclone ‘Roanu’ extracted from ECMWF Model (collaboration with met.no) based on the initial conditions of 0000 UTC of 19 May 2016

F i g. 1 3 : Surface wind and rainfall associated with cyclone ‘Roanu’ from ECMWF Model ( collaboration with met.no) based on the initial conditions of 0000 UTC of 19 May 2016

F i g. 1 4 : Surface wind (ms - 1 ) and vorticity (s - 1 ) associated with cyclone ‘Roanu’ from ECMWF Model (collaboration with met.no) based on the initial conditions of 0000 UT C of 19 May 2016

Fi g . 15 : Surface wind (ms - 1 ) and vorticity (s - 1 ) associated with cyclone ‘Roanu’ simulated by WRF model simulated based on the initial conditions of 0000 UTC of 17 May 2016

Fi g . 16 : Surface wind (ms - 1 ) and vorticity (s - 1 ) associated wi th cyclone ‘Roanu’ simulated by WRF model simulated based on the initial conditions of 0000 UTC of 18 May 2016

Fi g . 17 : Surface wind (ms - 1 ) and vorticity (s - 1 ) associated with cyclone ‘Roanu’ simulated by WRF model simulated based on the initial conditi ons of 0000 UTC of 19 May 2016

Fi g . 18 : Surface wind (ms - 1 ) and vorticity (s - 1 ) associated with cyclone ‘Roanu’ simulated by WRF model simulated based on the initial conditions of 0000 UTC of 20 May 2016

F i g. 1 9 : Surface wind (ms - 1 ) and vorticity (s - 1 ) associated with cyclone ‘Roanu’ simulated by operational WRF model at BMD based on the initial conditions of 0000 UTC of 20 May 2016

IMD GFS ( T 5 7 4 ) m e a n s e a le v e l p ress u re ( M S L P), w in d s a t 1 0 m , 85 0 , 5 0 0 a n d 20 0 h Pa le v e ls a re p res e n t e d in Fi g . 12 . GFS ( T 5 7 4 ) c ou ld si m u la t e th e g ene sis o f th e s y st e m an d t h e a s s o cia t e d ci r c u la t ion f e a t u res d u r i n g t h e l i f e p e r i o d o f CS Ro an u . Ho w e v e r, t h e de e p tro u g h in w e st e r l ies o n 2 0 May l y ing to t h e w e st o f t h e s y st e m c en tre c ou ld no t b e c ap t u r e d w e l l . In c o m p a r i s o n N C UM a n a l y sis c ou ld si m u la t e a n d track t h e s y st e m b e t t e r (Fig s . 20 - 23 ).

Fi g . 20 : IMD G FS M S L P, 1 0 m w ind a n d w in d s a t 85 0 , 5 0 0 an d 20 0 h Pa l e v e ls ba s e d o n 0 00 0 U T C o f 1 7 M a y 2016

Fi g . 21 : IMD GFS a na l y sis o f M S L P, 1 0 m w in d , w i nd s a t 8 50 , 5 0 0 a n d 2 5 0 h Pa ba s e d o n 00 0 0 U T C o f 1 9 May 20 1 6

Fi g . 22 : IMD GFS a na l y sis o f M S L P, 1 0 m w in d , w i nd s a t 8 50 , 5 0 0 a n d 2 5 0 h Pa ba s e d o n 00 0 0 U T C o f 20 M a y 2 0 1 6

Fi g . 23 : IMD GFS a na l y sis o f M S L P, 1 0 m w in d , w i nd s a t 8 50 , 5 0 0 a n d 2 5 0 h Pa ba s e d on 00 0 0 U T C o f 2 1 M a y 20 1 6

7 . Bul l e tins i ss ued b y BMD BMD c on ti nu o u sly m o n it o re d , p re d ic t e d a n d issu e d b u l l e ti n s c o n t a ini n g track & in ten sity f o r e c a st till t h e s y st e m w ea k ene d in t o a l o w p ress u re a re a . T h e a b o v e struct u red track an d in ten sity f o rec a sts w e re issu e d f r o m t h e s t a g e o f dee p d e p ression on w a rds. T h e c on e o f un c e rta i n ty in t h e track f o rec a st w a s a lso g i v e n . T h e g ra ph ical d ispl a y o f t h e ob s e r v e d a n d f o re c a st track w ith c on e o f un c e rta i n ty an d t h e w ind f o re c a st f o r d i f f e r e n t q uad ra n ts w e re up lo a d e d in t h e BMD w eb site ( h t tp : / /www.bmd.gov.bd ) re g u lar l y . T h e p ro g no stics a n d d ia g no stics o f t h e s y st em s w e re de scr i be d i n t h e BMD bu l l e ti n s a re briefly described in Table 2. Tab le 2 : Bul l e tins i s s u e d b y BMD, Dhaka Date Ti me Status Location Position Bulletin Signal Comments 15.05.2016 09 AM Low SW Bay and - - - - adjoining area 15.05.2016 03 PM Well SW Bay and - - - - Marked adjoining Si low Lanka 17.05.2016 12 Noon Depression SW Bay and Lat 11.0 °N, Special Ctg - 01 - 0600 adjoining area Lon 81.0°E Weather Cox - 01 UTC) Bulletin - 1 Mon - 01 Payra - 01 17.05.2016 Midnight Depression SW Bay and Lat 11.5°N, Special Ctg - 01 - (1800 adjoining area lon 81.0°E Weather Cox - 01 UTC) Bulletin - 2 Mon - 01 Payra - 01 18.05.2016 12 Noon Depression SW Bay and Lat 13.0°N, Special Ctg - 01 Fishing boats & Trawlers (0600 adjoining WC lon 80.8°E Weather Cox - 01 over north Bay and Deep UTC) Bay Bulletin - 3 Mon - 01 sea: Come close to the Payra - 01 coast and proceed with caution 18.05.2016 06 PM Deep WC Bay and Lat 13.5°N, Special Ctg - 01 Fishing boats & Trawlers (1200 Depression adjoining SW lon 81.0°E Weather Cox - 01 over north Bay and Deep UTC) Bay Bulletin - 4 Mon - 01 sea: proceed with caution Payra - 01 18.05.2016 Midnight Deep WC Bay and Lat 13.9°N, Special Ctg - 01 Fishing boats & Trawlers (1800 Depression a djoining SW lon 81.0°E Weather Cox - 01 over north Bay and Deep UTC) Bay Bulletin - 5 Mon - 01 sea: proceed with caution Payra - 01 19.05.2016 03 AM Deep WC Bay and Lat 14.3°N, Special Ctg - 01 Fishing boats & Trawlers Depression adjoining SW lon 81.1° E Weather Cox - 01 over north Bay and Deep Bay Bulletin - 6 Mong - 01 sea: proceed with caution Payra - 01 19.05.2016 09 AM Cyclonic WC Bay and Lat 15.0°N, Special C tg - 02 Fishing boats & Trawlers Storm adjoining SW lon 81.2°E Weather Cox - 02 over north Bay and Deep ‘Roanu’ Bay Bulletin - 7 Mon - 02 sea ahve been advised to Payra - 02 come close to the coast so that they can take shelter within a short notice. They are also advised not to venture into the deep sea. 19.05.2016 12 Noo n Cyclonic WC Bay and Lat 15.5°N, Special Ctg - 04 Fishing boats & Trawlers Storm adjoining SW lon 81.5°E Weather Cox - 04 over north Bay and Deep ‘Roanu’ Bay Bulletin - 8 Mon - 04 sea have been advised to Payra - 04 come close to the coast so that they can take s helter within a short notice. They are also advised not

Date Ti me Status Location Position Bulletin Signal Comments to venture into the deep sea. 19.05.2016 06 PM Cyclonic WC Bay and Lat 15.5°N, Special Ctg - 04 Fishing boats & Tr awlers Storm adjoining SW lon 81.5°E Weather Cox - 04 over north Bay and Deep ‘Roanu’ Bay Bulletin - 9 Mon - 04 sea have been advised to Payra - 04 remain close to the coast so that they can take shelter within a short notice. They are also advised not to venture into the deep sea. 19.05.2016 Midnight Cyclonic WC Bay and Lat 16.0°N, Special Ctg - 04 Fishing boats & Trawlers Storm adjoining area lon 81.9°E Weather Cox - 04 over North Bay and Deep ‘Roanu’ Bulletin - 10 Mon - 04 Sea have been advised to Payra - 04 remain close to the coast so that they can take shelter within a short notice. They are also a dvised not to venture into the deep sea. 20.05.2016 06:00 Cyclonic WC Bay and Lat 16.4°N, Special Ctg - 04 Fishing boats & Trawlers AM Storm adjoining area lon 82.6°E Weather Cox - 04 over North Bay and Deep ‘Roanu’ Bulletin - 11 Mon - 04 Sea have been advised to Payra - 04 remain close to the coast so that they can take shelter within a short notice. They are also advised not to venture into the deep sea. 20.05.2016 12:00 Cyclonic WC Bay and Lat 18.0°N, Special Ctg - 04 Fishing boats & Trawlers Noon Storm adjoining area lon 84.2°E Weat her Cox - 04 over North Bay and Deep ‘Roanu’ Bulletin - 12 Mon - 04 Sea have been advised to Payra - 04 remain close to the coast so that they can take shelter within a short notice. They are also advised not to venture into the deep sea. 20.05.2016 06:00 Cyclonic North Bay Lat 18.5°N, Special Ctg - 07 Fishing boats & Trawlers PM Storm and adjoining lon 85.0°E Weather Cox - 06 over North Bay and Deep ‘Roanu’ WC Bay Bulletin - 13 Mon - 07 Sea have been advised to Payra - 07 remain close to the coast so that they can take shelter within a short notice. They are also advised not to venture into the deep sea. 20.05.2016 09:00 Cyclonic North Bay Lat 19.5°N, Special Ctg - 07 Fishing boats & Trawlers PM Storm and adjoining lon 86.6°E Weather Cox - 06 over North Bay and Deep ‘Roanu’ WC Bay Bulletin - 14 Mon - 07 Sea have been advised to Payra - 07 take shelter immediately and will remain shelter till further notice. 20.05.2016 Midnight Cyclonic Northwest Lat 20.6°N , Special Ctg - 07 Fishing boats & Trawlers Storm Bay and lon 87.7°E Weather Cox - 06 over North Bay and Deep ‘Roanu’ adjoining Bulletin - 15 Mon - 07 Sea have been advised to Bangladesh Payra - 07 take shelter immediately coast and will remain shelter

Date Ti me Status Location Position Bulletin Signal Comments till further notice. 20.05.2016 03:00 Cyclonic Northwest Lat 20.6°N, Special Ctg - 07 Fishing boats & Trawlers AM Storm Bay and lon 88.7°E Weather Cox - 06 over North Bay and Deep ‘Roa nu’ adjoining Bulletin - 16 Mon - 07 Sea have been advised to Bangladesh Payra - 07 take shelter immediately coast and will remain shelter til l further notice. 20.05.2016 06:00 Cyclonic Northwest Lat 20.8°N, Special Ctg - 07 Fishing boats & Trawlers AM Storm Bay and lon 90.0°E Weather Cox - 06 over North Bay and Deep ‘Roanu’ adjoining Bulletin - 17 Mon - 07 Sea have been advi sed to Bangladesh Payra - 07 take shelter immediately coast and will remain shelter till further notice. 20.05.2016 09:00 Cyclonic Northwest Lat 21.5°N, Special Ctg - 07 Fishing boats & Trawlers AM Storm Bay and lon 90.7°E Weather Cox - 06 over North Bay and Deep ‘Roanu’ adjoining Bulletin - 18 Mon - 07 Sea have been advised to Bangladesh Payra - 07 take shelter immediately coast and will remain shelter till further notice. 20.05.2016 12:00 Cyclonic Started to Lat 22.0°N, Special Ctg - 07 Fishing boats & Trawlers Noon Storm cross Barisal - Lo n 91.0°E Weather Cox - 06 over North Bay and Deep ‘Roanu’ Chittagong Bulletin - 19 Mon - 07 Sea have been advised to coast near Payra - 07 take shelter immediately Chittagong and will remain shelter till further notice. 20.05.2016 12:00 Cyclonic Crossed - Special Ctg - 07 Fishing boats & Trawlers Noon Storm Barisal - Weather Cox - 06 over North Bay and Deep ‘Roanu ’ Chittagong Bulletin - 20 Mon - 07 Sea have been advised to coast near Payr - 07 take shelter immediately Chittagong and will remain shelter till further notice.

8 . Dam a ge due to C yclone Roanu As pe r t h e re po rt of print and electronic media and Department of Disaster Management (DDM) , o v e rall 1 , 10 , 6 8 4 f a m i l ies w e re pa rtially an d 29 , 1 6 8 f u l l y a f fe ct e d b y C yclone R o anu . 2 4 p eop l e lost their lives 2 w e r e re po rted m iss i n g (Table 3) . S om e d a ma g e pho t o g ra ph s from B an g la de s h Me t eo rol o g ical D epa r t me n t a re p res en t e d in Fig s . 24 - 27 . Table 3 : District wise list of damage and causalities due to the Cyclone Roanu No of affected family No of affected Pe ople Sl District Dead Injured Missing Partial Full Partial Full 1 Chittagong 49,330 17,912 19,401 19,912 12 - - 2 Cox’s Bazar 6,230 1,715 7,022 1,228 3 - - 3 Chandpur 12,500 510 7,000 450 - - - 4 Noakhali 14,000 6,500 3,270 1,300 3 - - 5 Feni 55 30 55 20 1 - 2 6 Laxmipur 16,000 - 17,000 0 1 1 - 7 Bagerhat ------8 Khulna 1,000 100 120 40 - - - 9 Satkhira ------10 Barisal 2,000 - 500 - - - - 11 Patuakhali 1,100 400 400 - 1 - - 12 Firozpur 9 1 9 1 - - - 13 Bhola 2,500 1,500 2,500 1,500 3 - - 14 Barguna 4,960 - 2,000 - - - - 15 Jhalakhati 1,000 500 200 50 - - - Total 110,684 29,168 59,477 24,501 24 1 2

(a) ( b ) ( b )

( c ) ( d )

( e ) ( f )

Fig. 24: (a) Volunteers of Red Crescent carried out publicity campaign to make the people aware of risks of cyclone and asked them to take shelter in safer place, (b) Red Cross volunteers call people to evacuate before “Roanu” hit in Cox’s Bazar, (c) Red Cross Volunteers are helping to people to move cyclone shelter, (d) People are moving to the Cyclone Shelter, (e) Villagers stay at a shelter center after their homes were hit by cyclone Roanu in southernmost coastal district of Bangladesh on May 21, 2016 and ( f ) Houses destroyed by cyclone Roanu at Banshkhali, Chittagong .

(a) ( b )

( c ) ( d )

( e ) ( f )

Fig. 25: (a) Cyclone Roanu unleashed heavy rain and strong winds (photo from Daily Newspaper), (b) People of Barguna district marooned by flash flood triggered by cyclone ‘Roanu’ , (c) Homes have been submerged or destroyed in landslides by cyclone wind and su rges, (d) Houses destroyed by cyclone Roanu , (e) People trying to salvage belongings from their ruined houses at Premashia in Banshkhali upazila of Chittagong and (f) A village destroyed by cyclone Roanu in Chittagong district of Bangladesh .

( a ) ( b )

( c ) ( d )

( e ) ( f )

Fig. 26: (a) A man wades in water in southernmost coastal district of Bangladesh, on May 21, 2016. Cyclone Roanu slammed into the Bangladesh coastlines after making landfall in a southernmost coastal district on Saturday afternoon, leaving a trail of devastation, (b) People carry useful materials during heavy rain in southernmost coastal district of Bangladesh, on May 21, 2016, (c) Storm Surge over southern district of Bangladesh, on May 21, 2016, (d) A man collects items from his house on Sunday that collapsed in the adjacent pond in Tojumuddin of Bhola during cyclone Roanu a day before, (e) Fishing boats are in anchor to avoid the risk of cyclone Roanu and (f) Corrugated tin s of the houses of the roofs are damaged and lying in water due to cyclone Roanu.

( a ) ( b )

( c ) ( d )

( e ) ( f )

Fig. 2 7 : (a) S everal local shops damaged in Boubazar area of Rangabali upazila in Patuakhali as cyclone Roanu makes landfall, (b) Coastal Bhola district faced damaging effects even before the cyclone hit the Banglad esh coast, (c) People look for shelter as tidal surge submerged residential areas of Cox’s Bazar town (Photo: Focus Bangla ), (d) Surging waters damaged the coastal embankment in Shahporir Dwip of Teknaf, Cox’s Bazar (Photo: Prothom Alo), (e) Cyclone Roanu crossed Bangladesh’s coast line, sea waters surged into coastal areas in Patenga, Chittagong in the morning of 21 May 2016 and (f) Bangladeshi villagers make their way to shelter in Cox's Bazar during 21 May 2016 9 . Tr a c k p r e di c ti o n b y N W P mode l s T rack p re d i c ti o n b y v ar io u s N W P m ode ls is p r e s en t e d in Fi g s. 28 - 3 3 . B a s e d o n initi a l c o n d itio n s o f 1 2 0 0 U T C o f 1 7 May , W RF - V AR a n d JMA s ho w e d d iss i pa ti o n o v e r s ea . All o t he r m o de ls e x c e p t UKMO p r e d ict e d l a n d f a ll t o t h e s o u th o f Chit ta g on g . UKMO p re d ict e d la n d f a ll p o i n t a t 2 2 . 6° N/ 91 . 5° E a t a r o un d 1 5 0 0 U T C o f 2 1 M a y . All m o de ls s u gg e st e d mo v e m en t o f c y clo n e close to ea st c oa st o f I nd ia a n d rec u r v a t u re

30 to w a rds B an g la de sh c oa s t.

F i g. 2 8 : ECMWF predicted trajectories of Cyclone Roanu at 0000 UTC of 19 May 2 016

F i g. 2 9 : ECMWF predicted trajectories of Cyclone Roanu at 0000 UTC of 20 May 2016

F i g. 30 : ECMWF predicted trajectories of Cyclone Roanu at 1200 UTC of 20 May 2016

F i g. 3 1 : ECMWF Ensemble prediction of trajectories of Cyclone Roanu at 0000 UTC of 19 May 2016

F i g. 3 2 : ECMWF Ensemble prediction of trajectories of Cyclone Roanu at 00 00 UTC of 20 May 2016

F i g. 3 3 : ECMWF Ensemble prediction of trajectories of Cyclone Roanu at 1200 UTC of 20 May 2016 T rack p re d i c ti o n b y v ar io u s N W P m ode ls is p r e s en t e d in Figs. 34 - 36 . B a s e d o n initi a l c o n d itio n s o f 1 2 0 0 U T C o f 1 7 May , W RF - V AR a n d JMA s ho w e d d iss i pa ti o n o v e r s ea . All o t he r m o de ls e x c e p t UKMO p r e d ict e d l a n d f a ll t o t h e s o u th o f Chit ta g on g . UKMO p re d ict e d la n d f a ll po i n t a t 2 2 . 6 ° N/ 91 . 5 ° E a t a r o un d 1 5 0 0 U T C o f 2 1 M a y . All m o de ls s u gg e st e d mo v e m en t o f c y clo n e

close to ea st c oa st o f I nd ia a n d recurvature to w a rds B an g la de sh c oa s t.

Fig. 3 4 : P r e di c t e d tra c k of Cyclone Ro a nu b ase d on 0 0 0 0 UTC of 1 8 M a y 2016 (Source: IMD) B a s e d o n i n itial c o n d it io n s o f 0 0 0 0 U T C o f 1 9 May 2016 , a ll m ode ls p r e d ict e d l a n d f a ll no rt h w e st o f Chi t t a g o ng . UKMO p re d ict e d l a n d f a ll clo s e to Chi t t a g on g a ro u n d 1 00 0 U TC o f 2 1 May . MM E a n d H W RF a lso p re d ict e d la nd f a ll close to Chit ta g on g a ro un d 1 80 0 U T C o f 21 May .

F ig . 3 5 : Predicted track of CS Roanu based on 0000 UTC of 19 May 2016 (Source: IMD)

F i g. 3 6 : P r e di c t e d tra c k of CS Ro a nu b ase d on 0 0 0 0 UTC of 2 0 M a y 2016 (Source: IMD)

10 . Rainfall p r e di c ti o n b y N W P mode l s Simulated rainfalls through different NWP models are depicted in Figs. 37 - 44.

Fi g . 3 7 : Rainfall (03 hourly) associated with cyclone ‘Roanu’ simulated by WRF model simulated based on the initial conditions of 0000 UTC of 17 May 2016

Fi g . 3 8 : Rainfall (03 hourly) associated with cyclone ‘Ro anu’ simulated by WRF model simulated based on the initial conditions of 0000 UTC of 18 May 2016

Fi g . 3 9 : Rainfall (03 hourly) associated with cyclone ‘Roanu’ simulated by WRF model simulated based on the initial conditions of 0000 UTC of 19 May 2016

F i g . 40 : Rainfall (03 hourly) associated with cyclone ‘Roanu’ simulated by WRF model simulated based on the initial conditions of 0000 UTC of 20 May 2016

F i g. 4 1 : Rainfall (03 hourly) associated with cyclone ‘Roanu’ simulated by operational WRF model at B MD based on the initial conditions of 0000 UTC of 20 May 2016

F i g. 4 2 : Rainfall (03 hourly) associated with cyclone ‘Roanu’ simulated by operational WRF model at BMD based on the initial conditions of 0000 UTC of 21 May 2016

(a) (b)

F i g. 4 3 : Satel lite derived (GsMap) rainfall associated with cyclone Roanu during (a) 19 May 2016, (b) 20 May 2016

F i g. 4 4 : Satellite derived (GsMap) rainfall associated with cyclone Roanu during 21 May 2016

(a) (b)

F i g. 4 5 : (a) Satellite derived Wind (m/s) at 12 UTC of 20 May 2016 and (b) ECMWF predicted wave height (m) at 06 UTC of 21 May 2016 associated with cyclone Roanu

F i g. 4 6 : ECMWF predicted Gusty Wind (m/s) at 12 UTC of 21 May 2016 associated with cyclone Roanu 11. He av y r a infa l l prediction b y H W RF model T h e f o re c a st rai n f a ll s w a t h s b y Hurricane WRF ( H W RF ) m o d e l a re p res e n t e d in Figs. 47 and 48. It i n d ica t e s t ha t t h e H W R F m ode l c ou ld p r e d ict t h e o c c u r r en ce o f ra i n f a ll a lo n g I nd ian c oa s t ( n o rth T am il N a d u an d A n dh r a Pra d e s h ) b a s e d o n i n itial c o n d itio n s o f 1 7 M ay , o v e r A ndh r a Pr a de sh an d s ou t h O d is h a c oa st ba s e d o n initi a l c on d itio n s o f 1 8 May. It c o u ld c ap t u re rai n f a ll o v e r no rth A n dh ra Pra d e s h , O d isha an d W e st B eng a l c oa st ba s e d o n initi a l c ond itio n s o f 1 9 May , O d isha a n d w e st B e n g a l c oa st ba s e d o n init i a l c ond iti o n s o f 2 0 a n d 21 May 2016 . I t also p re d ict e d o cc u r re n ce o f hea v y rai n f a ll o v e r B a n g la de sh an d ad jo i n i n g

no rth ea s t e rn s t a t e s o f I n d ia ba s e d o n t h e i n itial c o n d itio n s o f 1 7 May on w a rds.

(a) (b)

Fi g . 4 7 : H W R F rain s w a th (inc h ) ba s e d o n 0600 U TC of 17 May and 0000UTC of 18 May 2016 i n itial c o n d itio n s (Source: IMD)

(a) (b)

Fi g . 4 8 : H W R F rain s w a th (inc h ) ba s e d o n 0000 UTC of (a) 19May and (b) 20 May 2016 i n itial c o n d itio n s (Source: IMD)

12. St o rm S urge prediction Storm surge height predicted by BM D (using IIT - D Storm Surge Model) is depicted in Fig. 49. Pre d ict e d s u r g e b y I n d ian Na t io n a l Ce n tre f o r Oc ea n I n f o r ma t i o n S e rv i c e s ( INCOI S ) A d v an ce C i rculati o n (AD C IRC) mode l a re p res en t e d in Fi g . 50 . A D C IRC mode l run b y INCOIS p re d ic t e d t h e ma x i mu m s u r g e o f h e i g h t 0 .7 m a lo n g ea s t c oa st o f I nd ia nea r K a kin a da , A n d h ra Pr a de sh a t 1 2 0 0 U T C o f 1 9 M a y , 2 0 16 . N o i n un d a ti o n e x t en t w a s p re d ict e d b y t h e m o d e l a lo n g I nd ian c o a st. This mo d e l p re d ic t e d s u r g e he i g h t o f a bo u t 2 m n ea r Chit t a g on g a t t h e t i m e o f l a n d f a l l .

Fig. 4 9 : BMD pr e d i c ted (using IIT - D Storm Surge Model) s urge he i ght n ea r (a) Bangladesh coast and North Bay (large view) and ( b ) Bangladesh coast and North Bay (close view)

(a) (b)

Fig. 50 : INCOIS (India) m odel pr e d i c ted s urge he i ght n ea r (a) K a k i n a da c o as t, A n dhra P r a de s h a nd ( b ) Bangl a de s h c o as t (Source: IMD) II T - Del h i st o r m s u r g e mo d e l f o r v a r i ou s c oa st a l st a t e s o f I nd ia an d B a n g la d e s h p re d ict e d st o rm s u r g e o f h e i g h t 3 0 - 4 0 cm a t t h e time o f la nd f a ll n e a r Chit ta g on g ( F i g . 51 ). Ho w e v e r, t h e r e a l i z e d s u r g e w a s a ro u n d 1 - 1 .5 m a t t h e time o f l a n d f a l l . He n c e , II T Del h i m o de l un d er - p r e d ict e d t h e s to r m s u r g e .

(a) (b)

Fig. 5 1 : IIT - De l h i s t o rm s urge f o r ec a s t i ss u e d a t (a) 000 0 UTC of 2 0 M a y a nd (b) 030 0 UTC of 2 1 M a y 2016

13. A d v e r s e w ea t he r for ec a s t v e rifi ca tion T h e v e r i f ica t io n s o f a d v e rse w ea t he r l i ke he a vy rain fa l l , g a le w ind an d st o rm s u r g e f o rec a st iss u e d b y BMD a re p res e n t e d in T a b l e s 4 - 7 .

Table 4 : Recorded wind Speed related to cyclone Roanu Maximum Wind Direction Ti me (utc) Station Lat Lon speed Sandwip 22.48 91.43 38 kts/ 70 kph NE’ly 0740 utc Sitakunda 22.63 91.70 40 kts/74 kph E’ly 0715 utc Rangamati 22.63 92.15 16 kts/30 kph SSE’ly 0900 utc Comilla 23.43 91.18 40 kts/74kph SE’ly 0800 utc Chandpur 23.23 90.70 07kts/ 13kph E’ly 004 1 utc Maijdee Court 22.87 91.10 35 kts/65 kph E’ly 0700 - 0800 utc Feni 23.03 91.42 35 kts/65 kph W’ly 0930 utc Hatiya 22.45 91.10 30 kts/56 kph S’ly 0400 utc Cox’s Bazar 21.45 91.97 45 kts/ 83 kph SSE’ly 0336 and 0435 utc Kutubdia 21.82 91.85 30 kts/5 6 kph SE’ly 0800 utc Teknaf 20.87 92.30 31 kts/ 57 kph E’ly 0041 utc Khulna 22.78 89.57 20 kts/37 kph NE’ly 0530 utc Barisal 22.72 90.37 25 kts/46 kph NE’ly 0615 utc Patuakhali 22.33 90.33 32 kts/ 59 kph NNW’ly 0400 utc Khepupara 21.98 90.23 35 kts/65 kph NW’ly 0345 - 0356 utc Bhola 22.68 90.65 17 kts/32 kph NE’ly 0500 utc

Table 5 : Recorded rainfall (mm) related to cyclone Roanu during 17 - 22 May 2016 Dates Station Lat Lon 17 May 18 May 19 May 20 May 21 May 22 May Dhaka 23.77 90.38 0 22 1 21 52 Trace Mymensingh 24.73 90.42 0 23 19 2 8 0 Tangail 24.25 89.93 0 0 0 Trace 6 0 Faridpur 23.60 89.85 1 8 1 11 42 0 Madaripur 23.17 90.18 10 1 24 76 73 1 Chittagong (AP) 22.22 91.80 10 1 34 33 60 1 Sandwip 22.48 91.43 1 85 41 41 53 0 Sitakunda 22.63 9 1.70 10 66 26 49 68 0 Rangamati 22.63 92.15 18 18 14 32 86 0 Comilla 23.43 91.18 8 2 17 85 110 4 Chandpur 23.23 90.70 4 30 15 89 85 0 Maijdee Court 22.87 91.10 6 54 62 91 66 0 Feni 23.03 91.42 2 63 16 46 123 1 Hatiya 22.45 91.10 4 25 94 70 52 0 Cox’ s Bazar 21.45 91.97 4 2 76 93 69 Trace Kutubdia 21.82 91.85 15 Trace 43 73 65 18 Teknaf 20.87 92.30 1 2 97 118 16 42 Sylhet 24.90 91.88 182 119 4 40 48 5 Srimangal 24.30 91.73 10 21 13 11 83 10

Dates Station Lat Lon 17 May 18 May 19 May 20 May 21 May 22 May Rajshahi 24.37 88.70 0 0 57 Trace 0 0 Ishwardi 24.15 89. 03 0 0 5 0 0 0 Bogra 24.85 89.37 6 10 11 0 4 0 Rangpur 25.73 89.27 25 55 3 1 0 0 Dinajpur 25.65 88.68 63 66 3 0 0 0 Syedpur 25.75 88.92 38 43 1 0 0 0 Khulna 22.78 89.57 1 0 14 49 51 Trace Mongla 22.47 89.60 1 1 45 95 47 4 Satkhira 22.72 89.08 0 2 20 37 20 0 Jessore 23.20 89.33 22 1 51 9 12 2 Chuadanga 23.65 88.82 5 0 Trace 0 Trace 0 Barisal 22.72 90.37 0 6 30 158 98 21 Patuakhali 22.33 90.33 0 6 70 175 61 0 Khepupara 21.98 90.23 0 23 113 180 112 6 Bhola 22.68 90.65 7 8 33 169 73 Trace

Table 6 : Recorded storm surge situation during Cyclone ‘Roanu’

Station Lat Lon Observed Storm Surge Comments As per the opinion of BMD’s Kutubdia 21.82 91.85 03 - 04 Feet observer About 5 Feet during high tide Cox’s As per the opinion of BMD’s 21.45 91.97 and about 3 Feet during low Bazar Officer tide ** No storm surge was observed as per the remaining coastal observatories of BMD

Table 7 : District wise list of damage and causalities due to the Cyclone Roanu ( As pre the report prepared by Department of Disaster Management of Bangladesh) No of affected family No of affected People Sl District Dead Injured Missing Partial Full Partial Full 1 Chittagong 49,330 17,912 19,401 19,912 12 - - 2 Cox’s Bazar 6,230 1,715 7,022 1,228 3 - - 3 Chandpur 12,500 510 7,0 00 450 - - - 4 Noakhali 14,000 6,500 3,270 1,300 3 - - 5 Feni 55 30 55 20 1 - 2 6 Laxmipur 16,000 - 17,000 0 1 1 - 7 Bagerhat ------8 Khulna 1,000 100 120 40 - - - 9 Satkhira ------10 Barisal 2,000 - 500 - - - - 11 Patuakhali 1,100 400 400 - 1 - - 12 Firozpur 9 1 9 1 - - - 13 Bhola 2,500 1,500 2,500 1,500 3 - - 14 Barguna 4,960 - 2,000 - - - - 15 Jhalakhati 1,000 500 200 50 - - - Total 110,684 29,168 59,477 24,501 24 1 2

14. Su m m a r y a nd C o nc l us i o n T h e C yclone Ro an u f o r m e d f r o m a l o w p ress u re a rea o v e r s ou t h w e st Bay of Bengal and adjoining areas off S ri Lan k a c oa st o n 1 5 M a y 2016 an d c on c e n tra t e d in t o a well marked low (WML) in the afternoon of same day. It intensified into a Depression at noon of 17 May and further in ten si f i e d into Deep Depression in the afternoon of 18 May and then into a c y clo n ic st o rm a t 09 AM of 1 9 May . I t mo v e d n ea r l y no rth to no rt h - n o rth ea st w a rd s initially , then ea s t - no rth e a st w a rds an d finally c r o ss e d Barisal - Chittagong coast near Chittagong ( no r t h o f Chit ta g on g ) during 12 Noon to 05 PM (0600 - 1100 UTC) of 21 May 2016. Des p ite its l o n g jo u rn e y o v e r s ea , it d id n o t in t en s i f y i n to a s e v e re c y clo n ic st o r m . BMD u til i z e d a ll its re s ou rces t o m o n it o r an d p r e d ict t h e g e ne sis, track an d in ten s i f ic a ti o n o f Cyclone Ro a n u . T h e f o rec a s t o f i ts g ene sis, track, in ten si ty , time and location o f l a n d f a l l w e re p re d ict e d well w ith s u f f ic ie n t l e a d ti me . I t s mo v em e n t across the Bay is also p re d ict e d w e ll in ad v an ce . 15. Acknowledgements of RSMC New Delhi Regional Specialized Met eorological Centre (RSMC), New Delhi acknowledges the contribution of Bangladesh Meteorological Department for providing real time Radar Products for tracking the system and valuable information. IMD mentioned that D W R p ro du cts f r o m K h e pu p a ra a n d C o x ’s B a z a r he lp e d e s pe cially in mon i t o r i n g t h e s y st e m p r i o r to an d d u r i n g l an d f a ll in be t t e r e sti ma ti o n o f lo c a ti on , i n t en sity an d l a n d f a l l p roc e ss e s l i ke h ea v y rain fa l l , g a le w ind e t c . BMD also acknowledged the collaboration of Nowegian Meteorological Agency (met. no) for providing ECMWF Products to BMD. References

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