AWIO20 FMEE 261209
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER
IN THE SOUTHWEST INDIAN OCEAN
DATE: 26/01/2026 AT 1200 UTC
PART 1: WARNING SUMMARY
Nil.
PART 2 : TROPICAL WEATHER DISCUSSION
The basin displays a Monsoon Trough (MT) configuration across its whole width, between 06S and 15S. Convection is
moderate in convergence areas along the northern side of the MT and near Madagascar.
Our basin is currently under the influence of a dry phase of the MJO, which is not conducive to cyclogenesis. However,
as an equatorial Rossby wave crosses a Kelvin wave over the western part of the basin in the coming days, the
northwesterly monsoon flow should strengthen and make conditions more favorable for cyclogenesis on both sides of
Madagascar from the middle of the week. North of the Mascarene archipelago :
In relation, to a surge in the monsoon flow forecast for the coming days, a low-pressure system is expected to form
north of the Mascarene Islands by Wednesday. Some ensemble models, notably the EPS, suggest a possible
development into a tropical storm on Wednesday or Thursday. However, the lack of convergence in the lower layers on
the south side and the presence of a north-westerly shear on the edge of an upper-level cut-off are likely to limit the
potential for development. Even if it does not intensify, this low-pressure system could move close to Réunion or
Mauritius on Thursday or Friday. The risk of tropical storm formation north of the Mascarene archipelago is expected to become low from Wednesday
28th. In the Mozambique Channel :
A low-pressure system could form in the central part of the Mozambique Channel from Wednesday 28th. Its potential
for development is likely to be limited initially due to dry air in the mid-troposphere and weak low-level convergence on
the southern side. However, if a low-pressure system does develop, it could benefit from a favorable environment with
good upper divergence, low wind shear, and very warm surface waters (above 29°C). The AI models, as well as Arome
and its ensemble, are particularly reactive. Regardless of whether cyclogenesis occurs, very heavy rainfall is likely
throughout the coming week over the Comoros archipelago, northwestern Madagascar, and northern Mozambique in
the powerful and persistent monsoon flow established on the margins of this system. The likelihood for the formation of a tropical storm in the centre of the Mozambique Channel is expected to become low
from Wednesday 28th then moderate from Thursday 29th. 10-day outlook :
The arrival of a new Rossby wave from the east of the basin early February could improve low-level convergence within
the MT and enhance cyclogenesis potential over the central and eastern part of the basin.
AWIO20 FMEE 271103
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER
IN THE SOUTHWEST INDIAN OCEAN
DATE: 2026/01/27 A 1200 UTC
PART 1: WARNING SUMMARY
Nil, but system 08-20252026 will be monitored by RSMC La Reunion from 12 UTC.
PART 2 : TROPICAL WEATHER DISCUSSION:
The basin has a Monsoon Trough (MT) pattern east of 70E, between 08S and 10S. Convection is strong north of the Mozambique Channel in the monsoon flow slowdown area and around the zone of disturbed weather 08-20252026. Weak to moderate convection is also observed in the monsoon flow slowdown area to the northwest of the TM.
Our basin is currently under the influence of a dry phase of the MJO, which is not conducive to cyclogenesis. However, as an equatorial Rossby wave crosses a Kelvin wave over the western part of the basin in the coming days, the northwesterly monsoon flow should strengthen and make conditions more favorable for cyclogenesis on both sides of Madagascar from the middle of the week.
Zone of Disturbed Weather 08-20252026 :
Information at 09 UTC :
Estimated position: 16.0S / 51.9E
Movement : SSW 4kt
Maximum wind speed (averaged over 10 minutes): 20 kt
Estimated central pressure: 1009 hPa
For further information, please refer to bulletin WTIO30 to be issued at 12 UTC.
In the Mozambique Channel :
A low-pressure system could form in the central part of the Mozambique Channel from Wednesday 28th. Its potential for development is likely to be limited initially due to dry air in the mid-troposphere and weak low-level convergence on the southern side. However, if a low-pressure system does develop, it could benefit from a favorable environment with good upper divergence, low wind shear, and very warm surface waters (above 29oC). A southerly wind surge in the Channel is expected on Thursday and will strengthen on Friday, which will promote vorticity within the system. Most models react within the next five days, with the AROME model and its ensemble being particularly responsive from Thursday 29th onwards. Conversely, the American GFS model and its ensemble struggle to model a low in the Canal and slowly manage to deepen the depression at the end of the week east of Madagascar. The AI models and the European model are intermediate and reach the stage of a moderate tropical storm on Friday or Saturday.
Regardless of whether cyclogenesis occurs, very heavy rainfall is likely throughout the coming week over the Comoros archipelago, northwestern Madagascar, and northern Mozambique in the powerful and persistent monsoon flow established on the margins of this system.
The likelihood for the formation of a tropical storm in the centre of the Mozambique Channel is expected to become low from Wednesday 28th, moderate Thursday and finally, high from Friday 30th.
10-day outlook :
The arrival of a new Rossby wave from the east of the basin early February could improve low-level convergence within the MT and enhance cyclogenesis potential over the central and eastern part of the basin.
NOTA BENE: The likelihood is an estimate of the chance of genesis of a moderate tropical storm over the basin within the next five days:
Very low: less than 10% Moderate: 30% to 60% Very high: over 90%
Low: 10% to 30% High: 60% to 90%
The Southwestern Indian ocean basin extends from the Equator to 40S and from the african coastlines to 90E.
WTIO30 FMEE 271322
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 1/8/20252026
1.A ZONE OF DISTURBED WEATHER 8
2.A POSITION 2026/01/27 AT 1200 UTC:
WITHIN 40 NM RADIUS OF POINT 16.2 S / 52.0 E
(SIXTEEN DECIMAL TWO DEGREES SOUTH AND
FIFTY TWO DECIMAL ZERO DEGREES EAST)
MOVEMENT: SOUTH-SOUTH-EAST 4 KT
3.A DVORAK ANALYSIS: 1.0/1.0/S 0.0/0 H
4.A CENTRAL PRESSURE: 1009 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 20 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL
6.A EXTENSION OF WIND BY QUADRANTS (KM):
NIL
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1011 HPA / 500 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM
1.B FORECASTS (WINDS RADII IN KM):
12H: 2026/01/28 00 UTC: 16.7 S / 52.3 E, VENT MAX= 025 KT, TROPICAL
DISTURBANCE
24H: 2026/01/28 12 UTC: 17.2 S / 52.8 E, VENT MAX= 025 KT, TROPICAL
DISTURBANCE
36H: 2026/01/29 00 UTC: 17.9 S / 53.9 E, VENT MAX= 025 KT, TROPICAL
DISTURBANCE
48H: 2026/01/29 12 UTC: 18.5 S / 55.1 E, VENT MAX= 025 KT, TROPICAL
DISTURBANCE
60H: 2026/01/30 00 UTC: 19.0 S / 56.3 E, VENT MAX= 025 KT, TROPICAL
DISTURBANCE
72H: 2026/01/30 12 UTC: 19.7 S / 57.3 E, VENT MAX= 020 KT, TROPICAL
DISTURBANCE
2.B LONGER-RANGE OUTLOOK:
96H: 2026/01/31 12 UTC: 21.6 S / 58.4 E, VENT MAX= 020 KT, TROPICAL
DISTURBANCE
2.C ADDITIONAL INFORMATION:
T=CI=1.0
OVER THE PAST 12 HOURS, CONVECTIVE ACTIVITY HAS BEGUN TO ORGANIZE
EAST OF MADAGASCAR. THE CONDITIONS FOR INITIATING A DVORAK ANALYSIS
AT 1.0 ARE MET. THE LATEST SCATTEROMETRIC DATA FROM 0244Z HY-2C AND
0614Z ASCAT C SHOW THAT A LARGE CLOCKWISE CIRCULATION IS PRESENT ON
THE SURFACE. HOWEVER, MAXIMUM WINDS DO NOT EXCEED 20KT.
THE EAST-SOUTHEASTWARD TRACK OF THIS SYSTEM IS PRIMARILY DRIVEN BY
THE MONSOON FLOW IN THE ABSENCE OF A SUBTROPICAL RIDGE TO THE SOUTH.
FROM FRIDAY ONWARDS, THE PRESENCE OF THE SUBTROPICAL RIDGE IN THE
SOUTHEAST SHOULD FAVOR A SOUTHERN TRACK. OUR CURRENT FORECAST IS
BASED ON A CONSENSUS OF THE MAIN DETERMINISTIC MODELS.
SYSTEM 08 IS DEVELOPING IN AN UNFAVOURABLE ENVIRONMENT FOR ITS
DEVELOPMENT. ALTHOUGH THE SURFACE CONVERGENCE ON THE NORTHERN SIDE
REMAINS FAVOURABLE WITH THE PRESENCE OF THE MONSOON FLOW, IT IS
LACKING ON THE SOUTHERN SIDE. MODERATE TO STRONG DEEP SHEAR
ASSOCIATED WITH THE PRESENCE OF AN UPPER-LEVEL CUTOFF IN THE SOUTH
WILL PERSIST THROUGHOUT THE WEEK. THIS SHEAR FAVORS DRY AIR
INTRUSIONS INTO THE INNER CORE. THE LIKELIHOOD THAT IT WILL REACH THE
STAGE OF A MODERATE TROPICAL STORM REMAINS LOW. ON SATURDAY, THE
SYSTEM IS EXPECTED TO DISAPPEAR IN THE NORTHERN PART OF A
MID-LATITUDE LOW.
EXPECTED IMPACTS ON MAURITIUS :
- POSSIBLE HEAVY RAINS WITH ACCUMULATIONS EXCEEDING 100MM BETWEEN
WEDNESDAY NIGHT AND FRIDAY MORNING.
THE SYSTEM'S CURRENT INTENSITY DOES NOT JUSTIFY THE ISSUANCE OF
REGULAR WARNINGS. NEXT WARNING TOMORROW AT 0600Z.
发表于 2026-1-27 18:18
发表于 2026-1-27 18:58
发表于 2026-1-27 19:12
