RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 14/16/20202021
1.A MODERATE TROPICAL STORM 16 (JOBO)
2.A POSITION 2021/04/23 AT 0600 UTC:
WITHIN 20 NM RADIUS OF POINT 8.9 S / 44.0 E
(EIGHT DECIMAL NINE DEGREES SOUTH AND
FORTY FOUR DECIMAL ZERO DEGREES EAST)
MOVEMENT: WEST-NORTH-WEST 4 KT
3.A DVORAK ANALYSIS: 3.0/3.0/D 0.5/6 H
4.A CENTRAL PRESSURE: 1001 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 150 SW: 150 NW: 0
34 KT NE: 0 SE: 75 SW: 55 NW: 0
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1010 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP
1.B FORECASTS (WINDS RADII IN KM):
12H: 2021/04/23 18 UTC: 8.4 S / 42.9 E, VENT MAX= 035 KT, MODERATE TROPICAL
STORM
28 KT NE: 45 SE: 150 SW: 150 NW: 75
34 KT NE: 20 SE: 35 SW: 35 NW: 20
24H: 2021/04/24 06 UTC: 7.9 S / 41.8 E, VENT MAX= 030 KT, TROPICAL DEPRESSION
28 KT NE: 85 SE: 185 SW: 185 NW: 55
36H: 2021/04/24 18 UTC: 7.5 S / 40.7 E, VENT MAX= 025 KT, TROPICAL DEPRESSION
48H: 2021/04/25 06 UTC: 7.1 S / 39.5 E, VENT MAX= 025 KT, OVERLAND DEPRESSION
60H: 2021/04/25 18 UTC: 6.6 S / 38.2 E, VENT MAX= 020 KT, OVERLAND DEPRESSION
2.B LONGER-RANGE OUTLOOK:
NIL
2.C ADDITIONAL INFORMATION:
T=CI=3.0+
DURING THE LAST 6 HOURS, THE DEEP CONVECTION HAS BEEN MAINTAINED WITH
STILL COLD TOPS. IT IS LOCALIZED AT THE CENTER AND EXTENDS A LITTLE MORE
IN THE SOUTHEAST PART OF JOBO, DEFINING A CURVED BAND PATTERN. THE
DVORAK ANALYSIS OF 3.0+ ALLOWS TO ESTIMATE WINDS AROUND 40KT, BUT THE
LAST VISIBLE IMAGES SHOW A HOT SPOT IN THE CENTER OF THE CDO. THIS
CHARACTERISTIC CAN SUGGEST A BEGINNING OF A BOOST IN INTENSITY.
NOT MUCH CHANGE IN TERMS OF TRACK: JOBO CONTINUES ITS
WEST-NORTHWESTWARD TRACK, UNDER THE EFFECT OF THE MID-TROPOSPHERE
RIDGE LOCATED OVER THE CENTER OF THE MOZAMBIQUE CHANNEL AND THE
LOW-LEVEL FLOW OVER THE NORTHERN PART OF THE CHANNEL. THE DISPERSION
AMONG THE LATEST AVAILABLE GUIDANCE REMAINS LOW AND THE PRESENT
FORECAST IS A CONSENSUS OF THE MAIN SCENARIOS. JOBO IS NOW PASSING
BETWEEN 200 AND 300KM NORTH OF THE GREAT COMOROS ARCHIPELAGO. IT WILL
CONTINUE ITS TRACK TOWARDS TANZANIA WHICH IT WILL REACH ON SUNDAY (BE
CAREFUL IN THE PREVIOUS RSMC BULLETIN, AN ERROR WAS MADE ON THE
LANDING DAY). A LANDING IS FORECASTED NEAR DAR ES SALAM ON SUNDAY
MORNING.
AT 6 OR 12H TIME PERIODS, THE WESTERLY SHEAR COULD WEAKEN SLIGHTLY
ALLOWING JOBO TO TEMPORARILY MAINTAIN A MODERATE TROPICAL STORM
INTENSITY. THEREAFTER, THE SHEAR ORIENTING A LITTLE MORE
WEST-SOUTH-WEST THEN SOUTH-WEST IN THE MIDDLE TROPOSPHERE WILL
CONTINUE TO WEAKEN THE SYSTEM BEFORE ITS LANDING. THE SMALL SIZE OF
JOBO INDUCES A LARGER THAN AVERAGE UNCERTAINTY ON THE INTENSITY
FORECAST. IT MAY UNDERGO RAPID VARIATIONS IN INTENSITY.
IN TERMS OF EXPECTED IMPACTS, HEAVY RAINS ARE STILL EXPECTED ON THE
ISLANDS OF THE COMOROS ARCHIPELAGO IN THE MARGIN OF THE STORM THAT
CAN REACH 100 TO 200MM IN 24H, UNTIL THE END OF THE WEEK. GUSTS SHOULD
REMAIN MODEST AROUND 60 KM/H.
FOR TANZANIA, WITH THE WEAKENING OF THE JOBO SYSTEM AT THE LANDING,
THE IMPACTS COULD REMAIN LIMITED IN TERMS OF WIND BUT HEAVY RAINS ARE
EXPECTED AT THE LANDING ZONE.
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 14/16/20202021
1.A MODERATE TROPICAL STORM 16 (JOBO)
2.A POSITION 2021/04/23 AT 0600 UTC:
WITHIN 20 NM RADIUS OF POINT 8.9 S / 44.0 E
(EIGHT DECIMAL NINE DEGREES SOUTH AND
FORTY FOUR DECIMAL ZERO DEGREES EAST)
MOVEMENT: WEST-NORTH-WEST 4 KT
3.A DVORAK ANALYSIS: 3.0/3.0/D 0.5/6 H
4.A CENTRAL PRESSURE: 1001 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 150 SW: 150 NW: 0
34 KT NE: 0 SE: 75 SW: 55 NW: 0
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1010 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP
1.B FORECASTS (WINDS RADII IN KM):
12H: 2021/04/23 18 UTC: 8.4 S / 42.9 E, VENT MAX= 035 KT, MODERATE TROPICAL
STORM
28 KT NE: 45 SE: 150 SW: 150 NW: 75
34 KT NE: 20 SE: 35 SW: 35 NW: 20
24H: 2021/04/24 06 UTC: 7.9 S / 41.8 E, VENT MAX= 030 KT, TROPICAL DEPRESSION
28 KT NE: 85 SE: 185 SW: 185 NW: 55
36H: 2021/04/24 18 UTC: 7.5 S / 40.7 E, VENT MAX= 025 KT, TROPICAL DEPRESSION
48H: 2021/04/25 06 UTC: 7.1 S / 39.5 E, VENT MAX= 025 KT, OVERLAND DEPRESSION
60H: 2021/04/25 18 UTC: 6.6 S / 38.2 E, VENT MAX= 020 KT, OVERLAND DEPRESSION
2.B LONGER-RANGE OUTLOOK:
NIL
2.C ADDITIONAL INFORMATION:
T=CI=3.0+
DURING THE LAST 6 HOURS, THE DEEP CONVECTION HAS BEEN MAINTAINED WITH
STILL COLD TOPS. IT IS LOCALIZED AT THE CENTER AND EXTENDS A LITTLE MORE
IN THE SOUTHEAST PART OF JOBO, DEFINING A CURVED BAND PATTERN. THE
DVORAK ANALYSIS OF 3.0+ ALLOWS TO ESTIMATE WINDS AROUND 40KT, BUT THE
LAST VISIBLE IMAGES SHOW A HOT SPOT IN THE CENTER OF THE CDO. THIS
CHARACTERISTIC CAN SUGGEST A BEGINNING OF A BOOST IN INTENSITY.
NOT MUCH CHANGE IN TERMS OF TRACK: JOBO CONTINUES ITS
WEST-NORTHWESTWARD TRACK, UNDER THE EFFECT OF THE MID-TROPOSPHERE
RIDGE LOCATED OVER THE CENTER OF THE MOZAMBIQUE CHANNEL AND THE
LOW-LEVEL FLOW OVER THE NORTHERN PART OF THE CHANNEL. THE DISPERSION
AMONG THE LATEST AVAILABLE GUIDANCE REMAINS LOW AND THE PRESENT
FORECAST IS A CONSENSUS OF THE MAIN SCENARIOS. JOBO IS NOW PASSING
BETWEEN 200 AND 300KM NORTH OF THE GREAT COMOROS ARCHIPELAGO. IT WILL
CONTINUE ITS TRACK TOWARDS TANZANIA WHICH IT WILL REACH ON SUNDAY (BE
CAREFUL IN THE PREVIOUS RSMC BULLETIN, AN ERROR WAS MADE ON THE
LANDING DAY). A LANDING IS FORECASTED NEAR DAR ES SALAM ON SUNDAY
MORNING.
AT 6 OR 12H TIME PERIODS, THE WESTERLY SHEAR COULD WEAKEN SLIGHTLY
ALLOWING JOBO TO TEMPORARILY MAINTAIN A MODERATE TROPICAL STORM
INTENSITY. THEREAFTER, THE SHEAR ORIENTING A LITTLE MORE
WEST-SOUTH-WEST THEN SOUTH-WEST IN THE MIDDLE TROPOSPHERE WILL
CONTINUE TO WEAKEN THE SYSTEM BEFORE ITS LANDING. THE SMALL SIZE OF
JOBO INDUCES A LARGER THAN AVERAGE UNCERTAINTY ON THE INTENSITY
FORECAST. IT MAY UNDERGO RAPID VARIATIONS IN INTENSITY.
IN TERMS OF EXPECTED IMPACTS, HEAVY RAINS ARE STILL EXPECTED ON THE
ISLANDS OF THE COMOROS ARCHIPELAGO IN THE MARGIN OF THE STORM THAT
CAN REACH 100 TO 200MM IN 24H, UNTIL THE END OF THE WEEK. GUSTS SHOULD
REMAIN MODEST AROUND 60 KM/H.
FOR TANZANIA, WITH THE WEAKENING OF THE JOBO SYSTEM AT THE LANDING,
THE IMPACTS COULD REMAIN LIMITED IN TERMS OF WIND BUT HEAVY RAINS ARE
EXPECTED AT THE LANDING ZONE.