南半球各类图像自动更新暨非扰动云团专帖（2024年7月－2025年6月）

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AWIO20 FMEE 031110
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER
IN THE SOUTHWEST INDIAN OCEAN
DATE: 03/05/2025 AT 1200 UTC
PART 1: WARNING SUMMARY
Nil.
PART 2 : TROPICAL WEATHER DISCUSSION
The basin has a typical off-season pattern, with trans-equatorial trade winds migrating towards the northern
hemisphere. Convective activity remains weak and sparse, and is localized in the slowdown of the trade winds east of
75E north of the 6th parallel, as well as in the northern part of the channel east of the Comoros archipelago, in the
slowdown of the southeasterly flow.
The wave situation is generally unfavorable, due to a strong easterly anomaly near the equator. However, an anticyclonic
Equatorial Rossby wave could improve convergence along its southern edge.
Southeast of Rodrigues :
By the end of the weekend, low-level convergence could improve off southeast Rodrigues, between the easterly flow
driven by the subtropical ridge and the northwesterly flow maintained by the passage of a weak Equatorial Rossby
wave, with a fairly elongated structure. Environmental conditions are unfavorable, despite the passage of the vortex over
fairly warm surface waters over the weekend. The high vertical wind shear aloft associated with dry air in the mid-
troposphere does not suggest the development of cyclogenesis. Indeed, the latest numerical models suggest a
strengthening of the mean wind in the southern semicircle of this precursor, up to Near Gale Wind or even Gale force
wind according to GFS model, between Sunday and Monday, but of purely mechanical origin, with the tightening of the
pressure gradient. Finally, the ensemble models suggest a few rare scenarios of tropical storm development in this area.
The risk of cyclogenesis to the south-east of Rodrigues Island is now considered nil over the next few days.
For the next 5 days, there is no potential for this suspect area to develop into a moderate tropical storm.

红豆棒冰冰

ECMWF系集持续对南太有所反应

红豆棒冰冰

AWIO20 FMEE 051146
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER
IN THE SOUTHWEST INDIAN OCEAN
DATE: 05/05/2025 AT 1200 UTC
PART 1: WARNING SUMMARY
Nil.
PART 2 : TROPICAL WEATHER DISCUSSION
The basin has a Near Equatorial Trough (NET) configuration stretching between 54°E and 77°E and around 3°S.
Convective activity remains low, mostly close to the NET and around the convergences along the African coast to the
north of the Mozambique Channel.
The main feature of the start of the week is the return of a slightly positive MJO anomaly from the west of the basin,
which generates a westerly wind anomaly over the north-west of the basin. This anomaly is preceded by a weak Kelvin
wave moving further south, which is struggling to interact with a powerful Rossby wave crossing the basin and
contributes to the return of an established NET. Nevertheless, the context is still unfavorable with the predominance of
an easterly wind anomaly caused by the dry phase of the MJO over the east of the basin and the low frequency.
Development of a moderate tropical storm is not expected for the next 5 days.
The return of the wet phase of the MJO does not seem significant enough to be conducive to cyclogenesis. Only near-
equatorial latitudes may be affected by a westerly wind anomaly. No significant cyclogenesis signal.

红豆棒冰冰

ECMWF系集持续对南太有所反应

红豆棒冰冰

AWIO20 FMEE 061128
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER
IN THE SOUTHWEST INDIAN OCEAN
DATE: 06/05/2025 AT 1200 UTC
PART 1: WARNING SUMMARY
Nil.
PART 2 : TROPICAL WEATHER DISCUSSION
The basin has a Near Equatorial Trough (NET) configuration stretching between 62°E and 80°E and around 3°S.
Convective activity remains low, mostly close to the NET and a little more marked near the African coast north of the
Mozambique Channel.
The dominant context is given by the weakening of the wet phase of the MJO in the west of the basin and the gradual
establishment of the dry phase of the MJO in the east of the basin. This leaves a period unfavorable to cyclogenesis in
our basin.
Development of a moderate tropical storm is not expected for the next 5 days.
The wet phase of the MJO persisting over the western part of the basin does not seem significant enough to be
conducive to cyclogenesis. Only near-equatorial latitudes may be affected by a westerly wind anomaly. On subsequent
trends, there is therefore no cyclogenesis signal.

红豆棒冰冰

ECMWF系集持续对南太有所反应

红豆棒冰冰

AWIO20 FMEE 071133
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER
IN THE SOUTHWEST INDIAN OCEAN
DATE: 07/05/2025 AT 1200 UTC
PART 1: WARNING SUMMARY
Nil.
PART 2 : TROPICAL WEATHER DISCUSSION
The basin features a poorly defined and weakly convergent Near Equatorial Trough (NET) pattern stretching east of 47°E
and centered around 2-3°S. Convective activity is locally moderate to strong along the western/south-western edge of
the NET off the African coast and as far south as the Comoros. Convection is also marked along the northern and
northeastern border of the basin near the equator, in the equatorial westerlies associated with a transient Kelvin wave
followed by a weak MJO wet phase, but with wind convergences mostly present over the northern hemisphere tropics.
The weak wet phase of the MJO that will continue to cross the basin over the next few days should struggle to express
itself, being inhibited by both a near-equatorial easterly wind anomaly due to the weakly positive IOD, adding to the
current anticyclonic phase of a Rossby wave. The NET should therefore continue to lack convergence and vorticity over
the next few days, limiting cyclogenesis potential in the short term.
Development of a tropical storm is not expected over the next 5 days.
Extended outlook (D+5/D+10) :
Over the coming week, the wet phase of the MJO should shift towards the Indonesian region while gradually weakening,
overlapping with a powerful equatorial Rossby wave, which should enhance vorticity near the north-eastern border of
our basin in the second part of the week (from around May 15th onwards). Some members of the EPS and GEFS
ensembles suggest the formation of a tropical low that could develop into a tropical storm in a few scenarios, either in
the Indonesian area or over the north-eastern corner of our basin. We'll thus be keeping a close eye on this potential.

红豆棒冰冰

ECMWF系集持续对南太有所反应

红豆棒冰冰

AWIO20 FMEE 081115
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER
IN THE SOUTHWEST INDIAN OCEAN
DATE: 08/05/2025 AT 1200 UTC
PART 1: WARNING SUMMARY
Nil.
PART 2 : TROPICAL WEATHER DISCUSSION
The basin features a poorly defined and weakly convergent Near Equatorial Trough (NET) pattern stretching east of 70°E
and centered around 2-7°S. Convective activity is moderate on either side of the NET and off the African coast extending
as far as the Comoros Islands.
The weak wet phase of the MJO that will continue to cross the basin over the next few days should struggle to express
itself, being inhibited by both a near-equatorial easterly wind anomaly due to the weakly positive IOD, adding to the
current anticyclonic phase of a Rossby wave. The NET should therefore continue to lack convergence and vorticity over
the next few days, limiting cyclogenesis potential in the short term.
Development of a tropical storm is not expected over the next 5 days.
Extended outlook (D+5/D+10) :
Over the coming week, the wet phase of the MJO should shift towards the Indonesian region while gradually weakening,
overlapping with a powerful equatorial Rossby wave, which should enhance vorticity near the north-eastern border of
our basin in the second part of the week (from around May 15th onwards). Some members of the EPS and GEFS
ensembles suggest the formation of a tropical low that could develop into a tropical storm in a few scenarios, either in
the Indonesian area or over the north-eastern corner of our basin. We'll thus be keeping a close eye on this potential.

红豆棒冰冰

ECMWF系集持续对南太有所反应