ABIO10 PGTW 291230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN
REISSUED/291230Z-291800ZMAR2026//
RMKS/
1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH INDIAN OCEAN AREA (135E WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 99S) HAS PERSISTED NEAR 9.2S
76.0E, APPROXIMATELY 237 NM SOUTHEAST OF DIEGO GARCIA. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A DISORGANIZED LLCC WITH
FLARING CONVECTION AND ELEVATED WINDS BEGINNING TO WRAP ALONG THE
NORTHEASTERN PERIPHERY INTO THE SYSTEM. 99S IS CURRENTLY IN A MARGINALLY
FAVORABLE ENVIRONMENT FOR FURTHER DEVELOPMENT WITH VERY WARM (29-30 C)
SEA SURFACE TEMPERATURES, MODERATE POLEWARD OUTFLOW ALOFT, WHILE ALSO
BEING PLACED WITHIN A POCKET OF LIGHTER VERTICAL WIND SHEAR (10-15
KNOTS) OPPOSED TO THE SURROUNDING AREA (25-30 KNOTS). A FACTOR THAT CAN
NEGATIVELY AFFECT THE SYSTEM IS A LARGE DRY AIR MASS TO THE WEST THAT
WILL BE IN THE DIRECT PATH OF 99S AS IT CONTINUES TO DEVELOP. GLOBAL
DETERMINISTIC AND ENSEMBLE MODELS ARE IN GOOD AGREEMENT ON A
SOUTHWESTWARD TRANSIT AND SLIGHT INTENSIFICATION OVER THE NEXT 24-48
HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1008 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN
THE NEXT 24 HOURS IS LOW.
(2) NO OTHER SUSPECT AREAS.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: ADDED LOW AREA IN PARA 2.B.(1).//
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AWIO20 FMEE 291148
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER
IN THE SOUTHWEST INDIAN OCEAN
DATE: 2026/03/29 A 1200 UTC
PART 1: WARNING SUMMARY
NIL.
PART 2 : TROPICAL WEATHER DISCUSSION:
The basin features a monsoon trough (MT) that extends from 65oE to 88oE along 09oS. Convective activity is moderate north of the MT and weak in the northern part of the Mozambique Channel.
Despite a low-frequency environment causing easterly winds anomalies (positive IOD) over the central basin, an equatorial Rossby wave brings a surge of westerly winds that enhances equatorial convergence in the MT and, consequently, vorticity.
Over the central part of the basin :
Early next week, along the MT near 75E, the low-pressure circulation visible in the MSG satellite imagery could deepen in a favorable environment characterized by strong low-level convergence on both the equatorial and polar sides, as well as relatively weak upper-level wind shear. The ASCAT swath, which is outside the area, does not allow us to discern the hint of low-pressure circulation.
Ensemble models and AI scenarios do suggest the formation of a moderate tropical storm in most of their members by next Friday. The earliest deterministic models, such as the European model, show a tropical storm forming as early as Tuesday, while others reach this stage on Thursday the 2nd.
The likelihood of the formation of a moderate tropical storm becomes low from Tuesday, March the 31st, then moderate from Wednesday the 1st of April, south of Diego-Garcia.
10-day outlook:
10-day outlook : The Rossby wave moving westward across the basin will be supported by a moist MJO wave surging from the west of the basin by the end of next week.
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.
发表于 2026-3-29 19:33
