REGIONAL SPECIALISED METEOROLOGICAL CENTRE-TROPICAL CYCLONES, NEW DELHI
TROPICAL CYCLONE ADVISORY BULLETIN NO. 20
FROM: RSMC –TROPICAL CYCLONES, NEW DELHI
TO: STORM WARNING CENTRE, NAYPYI TAW (MYANMAR)
STORM WARNING CENTRE, BANGKOK (THAILAND)
STORM WARNING CENTRE, COLOMBO (SRILANKA)
STORM WARNING CENTRE, DHAKA (BANGLADESH)
STORM WARNING CENTRE, KARACHI (PAKISTAN)
METEOROLOGICAL OFFICE, MALE (MALDIVES)
OMAN METEOROLOGICAL DEPARTMENT, MUSCAT (THROUGH RTH JEDDAH)
YEMEN METEOROLOGICAL SERVICES, REPUBLIC OF YEMEN (THROUGH RTH JEDDAH)
NATIONAL CENTRE FOR METEOROLOGY, UAE (THROUGH RTH JEDDAH)
PRESIDENCY OF METEOROLOGY AND ENVIRONMENT, SAUDI ARABIA (THROUGH RTH JEDDAH)
IRAN METEOROLOGICAL ORGANISATION, (THROUGH RTH JEDDAH)
QATAR METEOROLOGICAL DEPARTMENT (THROUGH RTH JEDDAH)
TROPICAL CYCLONE ADVISORY NO. 20 FOR NORTH INDIAN OCEAN (THE BAY OF BENGAL AND
ARABIAN SEA) VALID FOR NEXT 120 HOURS ISSUED AT 1700 UTC OF 29.04.2019 BASED ON
1500 UTC OF 29.04.2019.
THE SEVERE CYCLONIC STORM ‘FANI’ (PRONOUNCED AS ‘FONI’) OVER SOUTHEAST & ADJOINING
SOUTHWEST BAY OF BENGAL MOVED NEARLY NORTHWARDS WITH A SPEED OF ABOUT 13 KMPH
TH
IN LAST SIX HOURS AND LAY CENTRED AT 1500 UTC OF 29 APRIL, 2019 NEAR LATITUDE 10.4°N
AND LONGITUDE 86.7°E OVER SOUTHEAST & ADJOINING SOUTHWEST BAY OF BENGAL, ABOUT
630 KM EAST-NORTHEAST OF TRINCOMALEE (43418), 760 KM EAST-SOUTHEAST OF CHENNAI
(43278) AND 880 KM SOUTH-SOUTHEAST OF MACHILIPATNAM (43185). IT IS VERY LIKELY TO
INTENSIFY INTO A VERY SEVERE CYCLONIC STORM DURING NEXT 24 HOURS AND INTO AN
EXTREMELY SEVERE CYCLONIC STORM DURING SUBSEQUENT 24 HOURS. IT IS VERY LIKELY TO
MOVE NORTHWESTWARDS TILL 01ST MAY EVENING AND THEREAFTER RECURVE NORTH-
NORTHEASTWARDS TOWARDS ODISHA COAST.
FORECAST TRACK AND INTENSITY ARE GIVEN IN THE FOLLOWING TABLE:
Date/Time(UTC) Position Maximum sustained Category of cyclonic
(Lat. 0N/ long. 0E) surface disturbance
wind speed (Kmph)
29.04.19/1500 10.4/86.7 100-110 gusting to 125 Severe Cyclonic Storm
29.04.19/1800 10.6/86.5 110-120 gusting to 135 Severe Cyclonic Storm
30.04.19/0000 11.2/86.2 120-130 gusting to 145 Severe Cyclonic Storm
30.04.19/0600 11.7/85.7 130-140 gusting to 155 Very Severe Cyclonic Storm
30.04.19/1200 12.2/85.1 135-145 gusting to 160 Very Severe Cyclonic Storm
01.05.19/0000 12.9/84.3 150-160 gusting to 175 Very Severe Cyclonic Storm
01.05.19/1200 13.5/83.6 160-170 gusting to 185 Extremely Severe Cyclonic Storm
02.05.19/0000 14.3/83.5 170-180 gusting to 200 Extremely Severe Cyclonic Storm
02.05.19/1200 15.4/83.6 170-180 gusting to 200 Extremely Severe Cyclonic Storm
03.05.19/0000 16.7/84.0 170-180 gusting to 200 Extremely Severe Cyclonic Storm
03.05.19/1200 18.2/84.7 170-180 gusting to 200 Extremely Severe Cyclonic Storm
04.05.19/0000 19.8/86.0 160-170 gusting to 185 Extremely Severe Cyclonic Storm
04.05.19/1200 21.0/87.3 150-160 gusting to 175 Very Severe Cyclonic Storm
PROBABILITY OF CYCLOGENESIS (FORMATION OF DEPRESSION)
NIL: 0%, LOW: 1-25%, FAIR: 26-50%, MODERATE: 51-75% AND HIGH: 76-100%
REMARKS:
TH
AS PER THE SATELLITE IMAGERY OF 1500 UTC ON 29 APRIL, 2019 THE CURRENT INTENSITY OF
THE SYSTEM OVER SOUTHEAST BAY OF BENGAL AND NEIGHBOURHOOD IS C.I 3.5. THE SYSTEM
HAS A CURVED BAND PATTERN. THE CONVECTION WRAP ON 10 DEGREE LOG SPIRAL OF 0.6 OF
0300 UTC INCREASED TO 0.8 YIELDING A DT OF 3.5. MET 3.5 AND PT 3.5. ASSOCIATED BROKEN
LOW TO MEDIUM CLOUDS WITH EMBEDDED INTENSE TO VERY INTENSE CONVECTION LAY OVER
SOUTH BAY OF BENGAL BETWEEN LATITUDE 8.0°N TO 13.5°N AND LONG 82.5°E TO 92.0°E.
MINIMUM CLOUD TOP TEMPERATURE IS MINUS 93°C.
THE ESTIMATED MAXIMUM SUSTAINED WIND SPEED IS 55 KNOTS GUSTING TO 65 KNOTS. THE
SEA CONDITION IS VERY HIGH AROUND THE SYSTEM CENTER. THE ESTIMATED CENTRAL
PRESSURE IS 992 HPA.
AT 1500 UTC OF TODAY, A BOUY (23460) LOCATED NEAR LAT. 6.5°N AND LONG 88.3°E REPORTED
MEAN SEA LEVEL PRESSURE 1009.0 HPA & MEAN WIND DIRECTION 240° & SPEED OF 19 KNOTS.
THE MADDEN JULIAN OSCILLATION (MJO) INDEX LIES CURRENTLY IN PHASE 4 WITH AMPLITUDE
MORE THAN 1. IT WILL CONTINUE IN SAME PHASE WITH AMPLITUDE GREATER THAN 1 FOR NEXT
2 DAYS. THEREAFTER IT WILL MOVE TO PHASE 5 WITH AMPLITUDE GRETAER THAN 1. HENCE,
MJO WILL BE FAVOURABLE FOR ENHANCEMENT OF CONVECTION & INTENSIFICATION OF THE
SYSTEM OVER BAY OF BENGAL.
THE SEA SURFACE TEMPERATURE (SST) IS 30-32˚C OVER WESTCENTRAL AND SOUTH BOB. THE
2
TROPICAL CYCLONE HEAT POTENTIAL IS AROUND 80-90 KJ/CM OVER THE SYSTEM AREA AND
INCREASES ALONG THE FORECAST TRACK. TOTAL PRECIPITABLE WATER VAPOUR IMAGERIES
INDICATE WARM AIR ADVECTION TO THE SYSTEM CENTRE.
-6 -1
THE LOWER LEVEL POSITIVE VORTICITY INCREASED AND IS ABOUT 200 X10 SEC AROUND THE
-5 -1
SYSTEM CENTER. THE LOW LEVEL CONVERGENCE IS 20-30 X10 SEC TO THE SOUTHWEST OF
-5 -1
THE SYSTEM CENTRE. UPPER LEVEL DIVERGENCE INCREASED AND IS NOW 30 X10 SEC TO
THE NORTHEAST OF THE SYSTEM CENTRE. VERTICAL WIND SHEAR IS LOW TO MODERATE (10-20
KNOTS) AROUND THE SYSTEM AND IT DECREASES ALONG THE FORECAST TRACK.
THE SYSTEM OVER SOUTHEAST AND ADJOINING BAY OF BENGAL IS LYING IN THE PERIPHERY OF
THE ANTICYCLONIC CIRCULATION OVER SOUTHEAST BAY OF BENGAL IN THE MIDDLE AND
UPPER TROPOSPHERIC LEVELS. THE SYSTEM WOULD BE STEERED BY THIS ANTICYCLONIC
ST
CIRCULATION LEADING TO NORTHWESTAWRD MOVEMENT TILL EVENING OF 01 MAY AND IT
WILL START RECURVING NORTHEASTWARDS FROM 0000 UTC OF 02 MAY 2019 TOWARDS ODISHA
COAST.
AS THE SYSTEM IS IN AN AREA OF LOW TO MODERATE VERTICAL SHEAR AND SIGNIFICANTLY
HIGH VALUES OF TROPICAL CYCLONE HEAT POTENTIAL, SYSTEM HAS INTENSIFIED INTO A
SEVERE CYCLONIC STORM. IT IS LIKELY TO FURTHER INTENSIFY DURING NEXT 24 HOURS.
THEREAFTER WITH THE EXPECTED RECURVATURE OF THE SYSTEM, IT IS LIKELY TO MOVE
NORTHEASTWARDS.
MOST OF THE NUMERICAL MODELS INCLUDING ECMWF, IMD GLOBAL FORECAST SYSTEM (GFS),
AND NCEP GFS, ARE IN AGREEMENT WITH THE ABOVE.
(ANANDA KUMAR DAS)
SCIENTIST-E, RSMC, NEW DELHI
PROBABILITY OF CYCLOGENESIS (FORMATION OF DEPRESSION)
NIL: 0%, LOW: 1-25%, FAIR: 26-50%, MODERATE: 51-75% AND HIGH: 76-100%
Severe Cyclonic Storm
‘FANI’ (10.4°N, 86.7°E)
PROBABILITY OF CYCLOGENESIS (FORMATION OF DEPRESSION)
NIL: 0%, LOW: 1-25%, FAIR: 26-50%, MODERATE: 51-75% AND HIGH: 76-100%
PROBABILITY OF CYCLOGENESIS (FORMATION OF DEPRESSION)
NIL: 0%, LOW: 1-25%, FAIR: 26-50%, MODERATE: 51-75% AND HIGH: 76-100%
