罗德里格斯岛以东强热带风暴第13号“伊沃娜”(23U/24S.Ivone) - 西南移动

ygsj24

WTIO31 FMEE 090725
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN INDIEN)

0.A NUMERO DU BULLETIN : 5/13/20242025
1.A TEMPETE TROPICALE MODEREE 13 (IVONE)

2.A POSITION A 0600 UTC LE 09/03/2025 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 15.5 S / 84.2 E
(QUINZE DEGRES CINQ SUD ET QUATRE-VINGT QUATRE DEGRES DEUX EST)
DEPLACEMENT: SUD-SUD-OUEST 8 KT

3.A ANALYSE DE DVORAK: 3.0/3.5/W 0.5/6 H

4.A PRESSION AU CENTRE: 997 HPA
5.A VENT MAX (MOYEN/10 MN): 40 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 610 SO: 510 NO: 75
34 KT NE: 0 SE: 490 SO: 350 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1007 HPA / 1000 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 09/03/2025 18 UTC: 17.7 S / 83.0 E, VENT MAX= 040 KT, TEMPETE TROPICALE
MODEREE
28 KT NE: 185 SE: 600 SO: 465 NO: 100
34 KT NE: 120 SE: 400 SO: 220 NO: 75

24H: 10/03/2025 06 UTC: 19.5 S / 82.0 E, VENT MAX= 045 KT, TEMPETE TROPICALE
MODEREE
28 KT NE: 175 SE: 650 SO: 405 NO: 85
34 KT NE: 110 SE: 415 SO: 280 NO: 0

36H: 10/03/2025 18 UTC: 20.2 S / 81.0 E, VENT MAX= 045 KT, TEMPETE TROPICALE
MODEREE
28 KT NE: 0 SE: 650 SO: 490 NO: 140
34 KT NE: 0 SE: 415 SO: 305 NO: 85

48H: 11/03/2025 06 UTC: 20.3 S / 79.2 E, VENT MAX= 040 KT, TEMPETE TROPICALE
MODEREE
28 KT NE: 0 SE: 490 SO: 530 NO: 85
34 KT NE: 0 SE: 305 SO: 260 NO: 0

60H: 11/03/2025 18 UTC: 20.1 S / 77.3 E, VENT MAX= 040 KT, TEMPETE TROPICALE
MODEREE
28 KT NE: 0 SE: 500 SO: 415 NO: 0
34 KT NE: 0 SE: 295 SO: 175 NO: 0

72H: 12/03/2025 06 UTC: 19.7 S / 74.7 E, VENT MAX= 035 KT, TEMPETE TROPICALE
MODEREE
28 KT NE: 0 SE: 455 SO: 335 NO: 0
34 KT NE: 0 SE: 280 SO: 120 NO: 0

2.B TENDANCE ULTERIEURE:
96H: 13/03/2025 06 UTC: 22.5 S / 68.7 E, VENT MAX= 035 KT, DEPRESSION RESIDUELLE
28 KT NE: 140 SE: 400 SO: 175 NO: 0
34 KT NE: 75 SE: 250 SO: 150 NO: 0

120H: 14/03/2025 06 UTC: 29.3 S / 67.4 E, VENT MAX= 035 KT, DEPRESSION RESIDUELLE
28 KT NE: 215 SE: 315 SO: 195 NO: 120
34 KT NE: 110 SE: 215 SO: 165 NO: 55

2.C COMMENTAIRES:
T=3.0+ CI=3.5-

AU COURS DES DERNIERES 6 HEURES, L'ACTIVITE CONVECTIVE A FAIBLI MAIS LA
CONFIGURATION NUAGEUSE EN BANDE SE MAINTIENT AVEC TOUTEFOIS UNE
ACTIVITE FAIBLE DANS LE QUADRANT NORD.L'ANALYSE DVORAK SUBJECTIVE EST
ABAISSEE A 3.0+. LA PASSE ASCAT DE 0343Z PERMET DE MESURER DES VENTS
MAXIMAUX DE 40KT DABS LE CADRAN SUD-OUEST, EN ACCORD AVEC L'ANALYSE
DVORAK SUBJECTIVE. IVONE RESTE AU STADE DE TEMPETE TROPICALE MODEREE.

PAS DE CHANGEMENT EN TERME DE PREVISION DE TRAJECTOIRE : IVONE SE
DEPLACE ACTUELLEMENT EN DIRECTION DU SUD-SUD-OUEST SOUS L'INFLUENCE
DE LA DORSALE A L'EST DU SYSTEME. A PARTIR DE LUNDI, L'ARRIVEE DE LA
DORSALE SUBTROPICALE AU SUD, DEVRAIT FAVORISER UN CHANGEMENT DE
TRAJECTOIRE EN DIRECTION DE L'OUEST JUSQU'EN MILIEU DE SEMAINE. A PARTIR
DE MERCREDI, LE SYSTEME DEVRAIT S'ORIENTER VERS LE SUD-OUEST EN
CONTOURNANT LA DORSALE PAR LE NORD-OUEST PUIS PLONGER PLUS
FRANCHEMENT VERS LE SUD.

PAS DE CHANGEMENT EN TERME D'INTENSITE, IVONE DISPOSE D'UNE COURTE
FENETRE FAVORABLE DANS LES PROCHAINES 24H AVEC UN CISAILLEMENT FAIBLE
ET UN FORT POTENTIEL OCEANIQUE. TOUTEFOIS, SON LARGE COEUR DEVRAIT
LIMITER SON RYTHME DE DEVELOPPEMENT.LA PREVISION DU CMRS PREVOIT UN
MAINTIEN AU STADE DE TEMPETE TROPICALE MODEREE. A PARTIR DE LUNDI, LE
SYSTEME DEVRAIT FAIBLIR SUITE AU RENFORCEMENT DU CISAILLEMENT D'OUEST
ET DES INTRUSIONS D'AIR SEC PLUS TARDIVEMENT. LE SYSTEME DEVRAIT ALORS
LENTEMENT SE COMBLER EN COURS DE SEMAINE PROCHAINE BIEN QU'IL
POURRAIT ENCORE PRESENTER DES VENTS FORTS DANS SA PARTIE SUD PAR EFFET
DE GRADIENT LORS DE SA DESCENTE VERS LE SUD.

AUCUN IMPACT SIGNIFICATIF N'EST ATTENDU POUR LES TERRES HABITEES.

ygsj24

WTXS31 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 24S (IVONE) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 24S (IVONE) WARNING NR 003   
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   090600Z --- NEAR 15.2S 84.1E
     MOVEMENT PAST SIX HOURS - 185 DEGREES AT 10 KTS
     POSITION ACCURATE TO WITHIN 045 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
                            220 NM SOUTHEAST QUADRANT
                            250 NM SOUTHWEST QUADRANT
                            070 NM NORTHWEST QUADRANT
   REPEAT POSIT: 15.2S 84.1E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   091800Z --- 17.2S 83.5E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
                            230 NM SOUTHEAST QUADRANT
                            210 NM SOUTHWEST QUADRANT
                            070 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 205 DEG/ 09 KTS
    ---
   24 HRS, VALID AT:
   100600Z --- 18.9S 82.7E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 010 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
                            230 NM SOUTHEAST QUADRANT
                            210 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 235 DEG/ 07 KTS
    ---
   36 HRS, VALID AT:
   101800Z --- 19.7S 81.5E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
                            240 NM SOUTHEAST QUADRANT
                            210 NM SOUTHWEST QUADRANT
                            070 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 265 DEG/ 10 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   110600Z --- 19.8S 79.4E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
                            230 NM SOUTHEAST QUADRANT
                            210 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 265 DEG/ 13 KTS
    ---
   72 HRS, VALID AT:
   120600Z --- 20.0S 73.9E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
                            160 NM SOUTHEAST QUADRANT
                            130 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 245 DEG/ 12 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   130600Z --- 22.0S 69.3E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
                            120 NM SOUTHEAST QUADRANT
                            140 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 120 HR POSIT: 215 DEG/ 12 KTS
    ---
   120 HRS, VALID AT:
   140600Z --- 26.0S 66.4E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
090900Z POSITION NEAR 15.7S 84.0E.
09MAR25. TROPICAL CYCLONE 24S (IVONE), LOCATED APPROXIMATELY 1558
NM EAST OF PORT LOUIS, MAURITIUS, HAS TRACKED SOUTHWARD AT 10
KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 090600Z
IS 993 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 090600Z IS 25 FEET.
NEXT WARNINGS AT 092100Z AND 100900Z. REFER TO TROPICAL CYCLONE
25S (JUDE) WARNINGS (WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES.//
NNNN

1. WDXS31 PGTW 090900
   
2. MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
   
3. SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 24S (IVONE)      
   
4. WARNING NR 003//
   
5. RMKS/
   
6. 1. FOR METEOROLOGISTS.
   
7. 2. 6 HOUR SUMMARY AND ANALYSIS.
   
8. 
   
9. SUMMARY:
   
10.    INITIAL POSITION: 15.2S 84.1E
    
11.    INITIAL INTENSITY: 45 KTS
    
12.    GEOGRAPHIC REFERENCE: 1558 NM EAST OF PORT LOUIS, MAURITIUS
    
13.    MOVEMENT PAST 6 HOURS: SOUTHWARD AT 10 KTS
    
14.    SIGNIFICANT WAVE HEIGHT: 25 FEET
    
15. 
    
16. SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
    
17. TROPICAL CYCLONE (TC) 24S HAS BECOME BETTER ORGANIZED OVER THE PAST
    
18. 12 HOURS AS INDICATED IN ANIMATED MULTISPECTRAL SATELLITE IMAGERY
    
19. (MSI), WHICH REVEALS DEEP CONVECTIVE BANDING WRAPPING AROUND A
    
20. PARTIALLY-EXPOSED, DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC). A
    
21. 090344Z ASCAT-B IMAGE SHOWS A BROAD CIRCULATION CENTER WITH GALE-FORCE
    
22. WINDS (35-40 KNOTS) PRIMARILY OVER THE EASTERN AND SOUTHERN
    
23. SEMICIRCLES WRAPPING INTO THE WESTERN QUADRANT, WITH SIGNIFICANTLY
    
24. WEAKER WINDS OVER THE NORTHERN QUADRANT. A 090319Z MHS 89GHZ MICROWAVE
    
25. IMAGE DEPICTS A DEEP CONVECTIVE BAND OVER THE SOUTHERN SEMICIRCLE
    
26. ASSOCIATED WITH THE CONVERGENT GALE-FORCE WINDS. WITH THE EXCEPTION OF
    
27. DRY AIR ENTRAINMENT INTO THE NORTHERN QUADRANT OF THE SYSTEM,
    
28. ENVIRONMENTAL CONDITIONS HAVE IMPROVED, WITH ROBUST POLEWARD OUTFLOW
    
29. AND LOW VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS PLACED WITH
    
30. MEDIUM CONFIDENCE BASED ON THE MSI AND RECENT ASCAT IMAGE. THE INITIAL
    
31. INTENSITY OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
    
32. PGTW AND DEMS DVORAK ESTIMATES, CONSISTENT WITH THE RECENT ASCAT DATA.
    
33. 
    
34. INITIAL WIND RADII BASIS: SCATTEROMETER DATA
    
35. 
    
36. CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE POSITIONED
    
37. TO THE SOUTHEAST.
    
38. 
    
39. AGENCY DVORAK AND AUTOMATED FIXES:
    
40.    PGTW: T3.0 - 45 KTS
    
41.    KNES: T2.5 - 35 KTS
    
42.    DEMS: T3.0 - 45 KTS
    
43.    CIMSS ADT: 49 KTS AT 090600Z
    
44.    CIMSS AIDT: 38 KTS AT 090600Z
    
45.    CIMSS D-PRINT: 27 KTS AT 090600Z
    
46. 
    
47. FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
    
48.    VWS: 0-5 KTS
    
49.    SST: 28-29 CELSIUS
    
50.    OUTFLOW: STRONG POLEWARD
    
51. 
    
52. ANALYSIS CONFIDENCE:
    
53.    INITIAL POSITION: MEDIUM
    
54.    INITIAL INTENSITY: MEDIUM
    
55.    INITIAL WIND RADII: MEDIUM
    
56. 
    
57. 3. FORECAST REASONING.
    
58. 
    
59. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
    
60. THE FORECAST FROM THE PREVIOUS WARNING.
    
61. 
    
62. FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 24S IS FORECAST TO TRACK
    
63. SOUTH-SOUTHWESTWARD THROUGH TAU 24 ALONG THE NORTHWESTERN PERIPHERY
    
64. OF A DEEP-LAYER SUBTROPICAL RIDGE (STR). THE SYSTEM SHOULD STEADILY
    
65. INTENSIFY TO A PEAK INTENSITY OF 50 KNOTS BY TAU 12 DUE TO THE ROBUST
    
66. POLEWARD OUTFLOW INTO A SUBTROPICAL JET TO THE SOUTH AND SOUTHEAST,
    
67. WARM SST VALUES (27-28C), AND LOW-MODERATE (5-20 KNOTS) VWS. AFTER
    
68. TAU 24, TC 24S WILL TRACK WESTWARD THROUGH TAU 72 ALONG THE NORTHERN
    
69. PERIPHERY OF A SECONDARY STR EXPECTED TO BUILD TO THE SOUTH.
    
70. SIGNIFICANT WEAKENING IS ANTICIPATED AS THE SUBTROPICAL JET TO THE
    
71. SOUTHEAST WEAKENS AND SHIFTS EAST, WITH INCREASING NORTHWESTERLY
    
72. UPPER-LEVEL FLOW AND HIGH (25-35 KNOTS) VWS OVER THE SYSTEM. AFTER TAU
    
73. 72, THE SYSTEM WILL BEGIN TO RECURVE SOUTHWESTWARD, WITH DISSIPATION
    
74. FORECAST BY TAU 120 AS EXTENSIVE DRY AIR ENVELOPS THE SYSTEM.
    
75. 
    
76. MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN FAIR AGREEMENT
    
77. THROUGH TAU 72, WITH A 190NM CROSS-TRACK SPREAD AT TAU 72. AFTER
    
78. TAU 72, THE GUIDANCE DIVERGES SIGNIFICANTLY, WITH A 290NM CROSS-TRACK
    
79. SPREAD AT TAU 120. PROBABILISTIC GUIDANCE FROM THE GEFS AND EPS
    
80. ENSEMBLES GENERALLY REVEAL A SIMILAR SPREAD SUPPORTING THE JTWC TRACK
    
81. FORECAST WITH MEDIUM CONFIDENCE.  
    
82. 
    
83. FORECAST CONFIDENCE:
    
84.    TRACK 0 - 72 HR: MEDIUM
    
85.    TRACK 72-120 HR: MEDIUM
    
86.    INTENSITY 0 - 72 HR: MEDIUM
    
87.    INTENSITY 72-120 HR: MEDIUM//
    
88. NNNN

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pocketbox

全球热带气旋监测公报
预报：王慧  签发：张 玲  2025 年 03 月 09 日 18 时
“伊沃娜”向南偏西方向移动

时       间：9日14时（北京时）

海       域：南印度洋

命       名：“伊沃娜”，IVONE

中心位置：南纬15.2度、东经84.1度

强度等级：热带风暴

最大风力：9级（23米/秒，相当于我国的热带风暴级）

中心气压：990百帕

参考位置：毛里求斯路易港偏东方向约2870公里的洋面上

变化过程：过去24小时，“伊沃娜”由8级加强到9级

预报结论：“伊沃娜”将以每小时20-25公里的速度向南偏西方向移动，强度逐渐增强。


图3 卫星红外监测图像（北京时间2025年03月09日14时00分）

ygsj24

WTIO30 FMEE 091327
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 6/13/20242025
1.A MODERATE TROPICAL STORM 13 (IVONE)

2.A POSITION 2025/03/09 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 17.0 S / 83.6 E
(SEVENTEEN DECIMAL ZERO DEGREES SOUTH AND
EIGHTY THREE DECIMAL SIX DEGREES EAST)
MOVEMENT: SOUTH 18 KT

3.A DVORAK ANALYSIS: 2.5/3.0/W 0.5/6 H

4.A CENTRAL PRESSURE: 998 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: 610 SW: 510 NW: 75
34 KT NE: 0 SE: 490 SW: 350 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2025/03/10 00 UTC: 18.7 S / 82.9 E, VENT MAX= 040 KT, MODERATE TROPICAL
STORM
28 KT NE: 165 SE: 585 SW: 445 NW: 110
34 KT NE: 110 SE: 380 SW: 215 NW: 85

24H: 2025/03/10 12 UTC: 20.3 S / 82.0 E, VENT MAX= 045 KT, MODERATE TROPICAL
STORM
28 KT NE: 95 SE: 630 SW: 465 NW: 140
34 KT NE: 0 SE: 405 SW: 325 NW: 100

36H: 2025/03/11 00 UTC: 20.5 S / 80.4 E, VENT MAX= 040 KT, MODERATE TROPICAL
STORM
28 KT NE: 0 SE: 600 SW: 510 NW: 110
34 KT NE: 0 SE: 380 SW: 285 NW: 55

48H: 2025/03/11 12 UTC: 20.3 S / 78.4 E, VENT MAX= 040 KT, MODERATE TROPICAL
STORM
28 KT NE: 0 SE: 500 SW: 490 NW: 0
34 KT NE: 0 SE: 295 SW: 240 NW: 0

60H: 2025/03/12 00 UTC: 19.9 S / 75.3 E, VENT MAX= 035 KT, MODERATE TROPICAL
STORM
28 KT NE: 0 SE: 400 SW: 325 NW: 0
34 KT NE: 0 SE: 240 SW: 140 NW: 0

72H: 2025/03/12 12 UTC: 20.4 S / 72.1 E, VENT MAX= 035 KT, REMNANT LOW
28 KT NE: 0 SE: 415 SW: 325 NW: 0
34 KT NE: 0 SE: 260 SW: 150 NW: 0

2.B LONGER-RANGE OUTLOOK:
96H: 2025/03/13 12 UTC: 22.8 S / 68.3 E, VENT MAX= 035 KT, REMNANT LOW
28 KT NE: 0 SE: 360 SW: 195 NW: 0
34 KT NE: 0 SE: 230 SW: 140 NW: 0

120H: 2025/03/14 12 UTC: 29.4 S / 68.5 E, VENT MAX= 035 KT, REMNANT LOW
28 KT NE: 140 SE: 380 SW: 185 NW: 0
34 KT NE: 0 SE: 230 SW: 100 NW: 0

2.C ADDITIONAL INFORMATION:
T=3.0+ CI=3.5

IN THE LAST 6 HOURS, CONVECTIVE ACTIVITY HAS INCREASED CLOSE TO THE
CENTER, BUT HAS DECREASED SIGNIFICANTLY IN THE PERIPHERAL AREA. THE
SHEAR CLOUD PATTERN SUGGESTS A DVORAK T NUMBER OF 3 OR EVEN 3.5. RSMC
ANALYSIS MAINTAINS IVONE AS A MODERATE TROPICAL STORM.

NO CHANGE IN TRACK FORECAST: IVONE IS CURRENTLY MOVING
SOUTH-SOUTH-WEST, UNDER THE INFLUENCE OF THE RIDGE OF HIGH PRESSURE TO
THE EAST OF THE SYSTEM. FROM MONDAY, THE ARRIVAL OF A SUBTROPICAL RIDGE
TO THE SOUTH SHOULD BRING A CHANGE IN TRACK TOWARDS THE WEST UNTIL
MID-WEEK. FROM WEDNESDAY ONWARDS, THE SYSTEM SHOULD MOVE
SOUTH-WESTWARDS, BYPASSING THE RIDGE TO THE NORTH-WEST AND THEN
HEADING MORE SIGNIFICANTLY SOUTHWARDS.

NO CHANGE IN TERMS OF INTENSITY, IVONE HAS A SHORT WINDOW OF
OPPORTUNITY OVER THE NEXT 24 HOURS, WITH WEAK SHEAR AND STRONG OCEAN
POTENTIAL. HOWEVER, ITS LARGE CORE SHOULD LIMIT ITS RATE OF
DEVELOPMENT. THE RSMC FORECAST CALLS FOR IT TO REMAIN A MODERATE
TROPICAL STORM. FROM MONDAY ONWARDS, THE SYSTEM SHOULD WEAKEN AS
WESTERLY SHEAR STRENGTHENS AND DRY AIR INTRUSIONS OCCUR LATER. THE
SYSTEM SHOULD THEN SLOWLY FILL IN OVER THE COURSE OF NEXT WEEK,
ALTHOUGH IT COULD STILL GENERATE STRONG WINDS IN ITS SOUTHERN PART DUE
TO THE GRADIENT EFFECT AS IT DESCENDS SOUTHWARDS.

NO SIGNIFICANT IMPACT IS EXPECTED ON INHABITED LAND.

Leonardo

TPXS10 PGTW 091504

A. TROPICAL CYCLONE 24S (IVONE)

B. 09/1430Z

C. 16.37S

D. 82.84E

E. SIX/MET9

F. T3.0/3.0/D0.5/24HRS  STT: S0.0/03HRS

G. IR/EIR

H. REMARKS: 47A/PBO PTLY XPSD LLCC/ANMTN. LLCC EMBEDDED 13NM IN
SHEARED DENSE OVERCAST YIELDS A DT OF 3.0. MET YIELDS 3.5. PT YIELDS
3.0. DBO DT.

I. ADDITIONAL POSITIONS:
   09/1232Z  17.28S  83.95E  SSMS



   RAE

---

TXXS28 KNES 091157
TCSSIO

A.  24S (IVONE)

B.  09/1130Z

C.  16.4S

D.  83.7E

E.  THREE/MET-9

F.  T2.5/2.5

G.  IR/EIR/SWIR

H.  REMARKS...5/10 BANDING ON A LOG10 SPIRAL YIELDS A DT OF 2.5. MET IS
A 2.0 DUE TO A SLOW DEVELOPING TREND IN SYSTEM. PT AGREES WITH DT. THE
FT IS BASED ON THE PT DUE TO BANDING FEATURES NOT BEING CLEAR CUT.

I.  ADDL POSITIONS

    NIL


...NGUYEN

=

ygsj24

WTIO30 FMEE 091935
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 7/13/20242025
1.A MODERATE TROPICAL STORM 13 (IVONE)

2.A POSITION 2025/03/09 AT 1800 UTC:
WITHIN 30 NM RADIUS OF POINT 17.4 S / 83.1 E
(SEVENTEEN    DECIMAL FOUR   DEGREES SOUTH AND
EIGHTY THREE    DECIMAL ONE   DEGREES EAST)
MOVEMENT: SOUTH-SOUTH-WEST 9 KT

3.A DVORAK ANALYSIS: 3.0/3.0/D 0.5/6 H

4.A CENTRAL PRESSURE: 995 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 45 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 435 SE: 600 SW: 600 NW: 260
34 KT NE: 175 SE: 335 SW: 405 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 900 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2025/03/10 06 UTC: 19.5 S / 82.3 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 260 SE: 545 SW: 470 NW: 295
34 KT NE: 150 SE: 335 SW: 325 NW: 0

24H: 2025/03/10 18 UTC: 20.2 S / 81.2 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 195 SE: 565 SW: 510 NW: 285
34 KT NE: 0 SE: 335 SW: 260 NW: 0

36H: 2025/03/11 06 UTC: 20.0 S / 79.1 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 0 SE: 575 SW: 545 NW: 205
34 KT NE: 0 SE: 325 SW: 240 NW: 0

48H: 2025/03/11 18 UTC: 19.9 S / 76.8 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 0 SE: 545 SW: 535 NW: 0
34 KT NE: 0 SE: 305 SW: 220 NW: 0

60H: 2025/03/12 06 UTC: 19.9 S / 73.2 E, VENT MAX= 035 KT, REMNANT
LOW
28 KT NE: 0 SE: 435 SW: 325 NW: 0
34 KT NE: 0 SE: 230 SW: 0 NW: 0

72H: 2025/03/12 18 UTC: 20.8 S / 70.1 E, VENT MAX= 035 KT, REMNANT
LOW
28 KT NE: 0 SE: 400 SW: 325 NW: 0
34 KT NE: 0 SE: 205 SW: 0 NW: 0

2.B LONGER-RANGE OUTLOOK:
96H: 2025/03/13 18 UTC: 24.2 S / 66.6 E, VENT MAX= 030 KT, REMNANT
LOW
28 KT NE: 0 SE: 380 SW: 315 NW: 0

120H: 2025/03/14 18 UTC: 31.3 S / 65.3 E, VENT MAX= 030 KT, REMNANT
LOW
28 KT NE: 405 SE: 405 SW: 0 NW: 0

2.C ADDITIONAL INFORMATION:
T=CI=3.0

OVER THE PAST 6 HOURS, CONVECTIVE ACTIVITY HAS STRENGTHENED NEAR THE
CENTER, WITH SUMMITS STILL VERY COLD. HOWEVER, IT REMAINS LIMITED TO
THE SOUTHERN SEMICIRCLE, UNDER THE INFLUENCE OF A NORTHERLY SHEAR AND
DRY AIR. THE 1614Z ASCAT PASS SHOWS A SLIGHT STRENGTHENING OF WINDS
IN THE SOUTHERN SEMICIRCLE (45KT). IT ALSO SHOWS THAT THE CIRCULATION
CORE IS VERY ELONGATED, IN RELATION TO CONVECTIVE ASYMMETRIES. THE
CENTER'S POSITION REMAINS SOMEWHAT UNCERTAIN.

NO CHANGE IN TRACK FORECAST: IVONE IS CURRENTLY MOVING
SOUTH-SOUTH-WEST, UNDER THE INFLUENCE OF THE RIDGE OF HIGH PRESSURE
TO THE EAST OF THE SYSTEM. FROM MONDAY, THE ARRIVAL OF A SUBTROPICAL
RIDGE TO THE SOUTH SHOULD BRING A CHANGE IN TRACK TOWARDS THE WEST
UNTIL MID-WEEK. FROM WEDNESDAY ONWARDS, THE SYSTEM SHOULD MOVE
SOUTH-WESTWARDS, BYPASSING THE RIDGE TO THE NORTH-WEST AND THEN
HEADING MORE SIGNIFICANTLY SOUTHWARDS.

IN TERMS OF INTENSITY, IVONE NO LONGER SEEMS TO HAVE A FAVORABLE
PERIOD FOR DEVELOPMENT. HOWEVER, THE SYSTEM COULD REMAIN CLOSE TO ITS
CURRENT INTENSITY OVER THE NEXT 24 HOURS. BEYOND THAT, WESTERLY SHEAR
AND DRY AIR INTRUSIONS SHOULD LEAD TO A SLOW FILLING OF IVONE DURING
NEXT WEEK. IT COULD STILL MAINTAIN GALES IN ITS SOUTHERN PART DUE TO
THE GRADIENT EFFECT.

NO SIGNIFICANT IMPACT IS EXPECTED ON INHABITED LAND.=

ygsj24

WTXS31 PGTW 092100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 24S (IVONE) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 24S (IVONE) WARNING NR 004   
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   091800Z --- NEAR 17.4S 83.1E
     MOVEMENT PAST SIX HOURS - 205 DEGREES AT 12 KTS
     POSITION ACCURATE TO WITHIN 060 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT
                            140 NM SOUTHEAST QUADRANT
                            140 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT
                            260 NM SOUTHEAST QUADRANT
                            200 NM SOUTHWEST QUADRANT
                            100 NM NORTHWEST QUADRANT
   REPEAT POSIT: 17.4S 83.1E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   100600Z --- 19.1S 82.2E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
                            170 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            250 NM SOUTHEAST QUADRANT
                            180 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 240 DEG/ 07 KTS
    ---
   24 HRS, VALID AT:
   101800Z --- 19.8S 80.8E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
                            140 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
                            240 NM SOUTHEAST QUADRANT
                            180 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 275 DEG/ 08 KTS
    ---
   36 HRS, VALID AT:
   110600Z --- 19.7S 79.0E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            210 NM SOUTHEAST QUADRANT
                            160 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 275 DEG/ 12 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   111800Z --- 19.5S 76.5E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            210 NM SOUTHEAST QUADRANT
                            130 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 265 DEG/ 14 KTS
    ---
   72 HRS, VALID AT:
   121800Z --- 20.1S 70.6E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            160 NM SOUTHEAST QUADRANT
                            130 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 235 DEG/ 12 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   131800Z --- 22.9S 66.4E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
                            140 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 120 HR POSIT: 200 DEG/ 10 KTS
    ---
   120 HRS, VALID AT:
   141800Z --- 26.5S 64.8E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
092100Z POSITION NEAR 17.8S 82.9E.
09MAR25. TROPICAL CYCLONE 24S (IVONE), LOCATED APPROXIMATELY 876
NM SOUTHEAST OF DIEGO GARCIA, HAS TRACKED SOUTH-SOUTHWESTWARD AT
12 KNOTS OVER THE PAST SIX HOURS.
MINIMUM CENTRAL PRESSURE AT 091800Z IS 993 MB. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 091800Z IS 27 FEET.
NEXT WARNINGS AT 100900Z AND 102100Z.
REFER TO TROPICAL CYCLONE 25S (JUDE) WARNINGS (WTXS32 PGTW)
FOR TWELVE-HOURLY UPDATES.//
NNNN

1. WDXS31 PGTW 092100
   
2. MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
   
3. SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 24S (IVONE) WARNING NR
   
4. 004//
   
5. RMKS/
   
6. 1. FOR METEOROLOGISTS.
   
7. 2. 6 HOUR SUMMARY AND ANALYSIS.
   
8. 
   
9. SUMMARY:
   
10.    INITIAL POSITION: 17.4S 83.1E
    
11.    INITIAL INTENSITY: 50 KTS
    
12.    GEOGRAPHIC REFERENCE: 876 NM SOUTHEAST OF DIEGO GARCIA
    
13.    MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 12 KTS
    
14.    SIGNIFICANT WAVE HEIGHT: 27 FEET
    
15. 
    
16. SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
    
17. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
    
18. CYCLONE 24S (IVONE) WITH A LARGE AREA OF CONVECTION OBSCURING THE
    
19. CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC). NORTHERLY SHEAR
    
20. CAN BE SEE ACTING ON THE SYSTEM ALONG WITH DRY AIR WITHIN THE
    
21. NORTHERN SEMICIRCLE, CAUSING THE LOW-LEVEL CLOUD LINES TO BE
    
22. EXPOSED IN THAT REGION. THESE TWO FACTORS ARE INHIBITING CONVECTIVE
    
23. DEVELOPMENT WITHIN THE NORTHERN PORTION OF THE SYSTEM. ENVIRONMENTAL
    
24. ANALYSIS INDICATES THAT 24S IS IN A MARGINALLY FAVORABLE
    
25. ENVIRONMENT CHARACTERIZED BY THE DRY AIR AND NORTHERLY VERTICAL
    
26. WIND SHEAR OFFSET BY THE STRONG POLEWARD OUTFLOW AND WARM (27-28 C)
    
27. SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH
    
28. MEDIUM CONFIDENCE BASED ON THE ANIMATED EIR. ADDITIONALLY, A
    
29. 091616Z METOP-B ASCAT IMAGE REVAELED AN ELONGATED LLCC IN THE
    
30. NORTH-SOUTH AXIS, SUPPORTING THE INITIAL POSITION. THE INITIAL
    
31. INTENSITY OF 50 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE
    
32. MENTIONED ASCAT SHOWING A WSATH OF 40 KTS WITHIN THE SOUTHERN
    
33. SEMICIRCLE AND ALL AGENCIES AGREEING ON A T3.0 ESTIMATE.
    
34. 
    
35. INITIAL WIND RADII BASIS: SCATTEROMETER DATA
    
36. 
    
37. CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A SUBTROPICAL
    
38. RIDGE (STR) POSITIONED TO THE EAST.
    
39. 
    
40. AGENCY DVORAK AND AUTOMATED FIXES:
    
41.    PGTW: T3.0 - 45 KTS
    
42.    KNES: T3.0 - 45 KTS
    
43.    DEMS: T3.0 - 45 KTS
    
44.    FMEE: T3.0 - 45 KTS
    
45.    FIMP: T3.0 - 45 KTS
    
46.    CIMSS SATCON: 44 KTS AT 091749Z
    
47. 
    
48. FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
    
49.    VWS: 10-15 KTS
    
50.    SST: 27-28 CELSIUS
    
51.    OUTFLOW: STRONG POLEWARD
    
52.    OTHER FACTORS: DRY AIR ENTRAINMENT
    
53. 
    
54. ANALYSIS CONFIDENCE:
    
55.    INITIAL POSITION: MEDIUM
    
56.    INITIAL INTENSITY: HIGH
    
57.    INITIAL WIND RADII: HIGH
    
58. 
    
59. 3. FORECAST REASONING.
    
60. 
    
61. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
    
62. THE FORECAST FROM THE PREVIOUS WARNING.
    
63. 
    
64. FORECAST DISCUSSION: TC 24S IS FORECAST TO CONTINUE TRACKING
    
65. SOUTH-SOUTHWESTWARD ALONG THE WESTERN PERIPHERY OF THE STR THROUGH
    
66. TAU 24. AFTER TAU 24, A BUILDING RIDGE WILL FORM SOUTH OF THE
    
67. SYSTEM AND BECOME THE PRIMARY STEERING INFLUENCE. THIS WILL DRIVE
    
68. 24S WESTWARD THROUGH TAU 72. NEAR TAU 72, 24S WILL BEGIN TO ROUND
    
69. THE RIDGE AND WILL TURN SOUTHWARD. REGARDING INTENSITY, 24S IS
    
70. FORECAST TO MAINTAIN INTENSITY THROUGH TAU 24 AS SHEAR REMAINS
    
71. RELATIVELY LOW. HOWEVER, AFTER TAU 24, SHEAR INCREASES TO AROUND 30
    
72. KTS. THE SHEAR ALONG WITH DRY AIR ENTRAINMENT WILL CAUSE 24S TO
    
73. WEAKEN, THOUGH ONLY MARGINALLY DUE TO THE ROBUST POLEWARD OUTFLOW
    
74. CHANNEL. NEAR TAU 96, SHEAR WILL INCREASE TO OVER 35 KTS AND DRY
    
75. AIR WILL COMPLETELY ERODE THE VORTEX, CAUSING DISSIPATION BY TAU
    
76. 120.
    
77. 
    
78. MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
    
79. THROUGH TAU 72 WITH A 180 NM CROSS-TRACK SPREAD AT TAU 72. AFTER
    
80. TAU 72, MODELS DIVERGE AND CROSS-TRACK SPREAD INCREASES TO AROUND
    
81. 500 NM AT TAU 120. NAVGEM TAKES THE SYSTEM NEARLY STRAIGHT WESTWARD
    
82. WHILE THE ECMWF ENSEMBLE MEAN RACES THE VORTEX SOUTHWARD. AS A
    
83. RESULT, THE JTWC TRACK FORECAST IS PLACED WITH MEDIUM CONFIDENCE
    
84. THROUGH TAU 72 AND LOW CONFIDENCE THEREAFTER. INTENSITY GUIDANCE IS
    
85. IN MODERATE AGREEMENT, WITH MODELS OVERALL PORTRAYING MARGINAL
    
86. WEAKENING THROUGH TAU 72 AND QUICKER WEAKENING AFTERWARD. THE JTWC
    
87. INTENSITY FORECAST IS PLACED WITH MEDIUM CONFIDENCE.
    
88. 
    
89. FORECAST CONFIDENCE:
    
90.    TRACK 0 - 72 HR: MEDIUM
    
91.    TRACK 72-120 HR: LOW
    
92.    INTENSITY 0 - 72 HR: MEDIUM
    
93.    INTENSITY 72-120 HR: MEDIUM//
    
94. NNNN

复制代码

yhh

WTIO30 FMEE 100104
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 8/13/20242025
1.A MODERATE TROPICAL STORM 13 (IVONE)

2.A POSITION 2025/03/10 AT 0000 UTC:
WITHIN 30 NM RADIUS OF POINT 17.9 S / 82.9 E
(SEVENTEEN    DECIMAL NINE   DEGREES SOUTH AND
EIGHTY TWO    DECIMAL NINE   DEGREES EAST)
MOVEMENT: SOUTH-SOUTH-WEST 8 KT

3.A DVORAK ANALYSIS: 3.0/3.0/S 0.0/6 H

4.A CENTRAL PRESSURE: 995 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 45 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 435 SE: 600 SW: 600 NW: 260
34 KT NE: 175 SE: 335 SW: 405 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 900 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2025/03/10 12 UTC: 19.8 S / 81.8 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 390 SE: 610 SW: 565 NW: 335
34 KT NE: 0 SE: 380 SW: 370 NW: 230

24H: 2025/03/11 00 UTC: 20.2 S / 80.2 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 305 SE: 620 SW: 565 NW: 250
34 KT NE: 0 SE: 380 SW: 370 NW: 165

36H: 2025/03/11 12 UTC: 19.8 S / 78.0 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 10 SE: 630 SW: 630 NW: 0
34 KT NE: 0 SE: 380 SW: 370 NW: 0

48H: 2025/03/12 00 UTC: 19.7 S / 74.6 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 0 SE: 640 SW: 575 NW: 0
34 KT NE: 0 SE: 400 SW: 370 NW: 0

60H: 2025/03/12 12 UTC: 20.1 S / 71.6 E, VENT MAX= 030 KT, REMNANT
LOW
28 KT NE: 0 SE: 565 SW: 480 NW: 0

72H: 2025/03/13 00 UTC: 21.0 S / 68.8 E, VENT MAX= 030 KT, REMNANT
LOW
28 KT NE: 0 SE: 490 SW: 0 NW: 0

2.B LONGER-RANGE OUTLOOK:
96H: 2025/03/14 00 UTC: 25.9 S / 65.5 E, VENT MAX= 030 KT, REMNANT
LOW
28 KT NE: 0 SE: 335 SW: 0 NW: 0

2.C ADDITIONAL INFORMATION:
T=CI=3.0-

OVER THE LAST 6 HOURS, CONVECTIVE ACTIVITY HAS PERSISTED IN THE
SOUTHEASTERN QUADRANT WITH VERY COLD TOPS, BUT APPEARS LESS PRESENT
IN THE SOUTHWESTERN QUADRANT ON CONVENTIONAL IMAGERY. THIS IS
CONFIRMED BY THE LATEST MICROWAVE IMAGES (GMI 0009Z). THIS STRUCTURE
IS PROBABLY THE CONSEQUENCE OF THE WEST- NORTH-WESTERLY SHEAR PRESENT
IN THE MID-TROPOSPHERE. IN THE ABSENCE OF RELIABLE ESTIMATES, THE
INTENSITY IS MAINTAINED AT 45KT.

NO CHANGE IN TRACK FORECAST: IVONE IS CURRENTLY MOVING
SOUTH-SOUTH-WEST, UNDER THE INFLUENCE OF THE RIDGE OF HIGH PRESSURE
TO THE EAST OF THE SYSTEM. TODAY, THE ARRIVAL OF A SUBTROPICAL RIDGE
TO THE SOUTH SHOULD BRING A CHANGE IN TRACK TOWARDS THE WEST UNTIL
MID-WEEK. FROM WEDNESDAY ONWARDS, THE SYSTEM SHOULD MOVE
SOUTH-WESTWARDS, BYPASSING THE RIDGE TO THE NORTH-WEST AND THEN
HEADING MORE SIGNIFICANTLY SOUTHWARDS.

IN TERMS OF INTENSITY, IVONE NO LONGER SEEMS TO HAVE A FAVORABLE
PERIOD FOR DEVELOPMENT. HOWEVER, THE SYSTEM COULD REMAIN CLOSE TO ITS
CURRENT INTENSITY OVER THE NEXT 24 HOURS. BEYOND THAT, WESTERLY SHEAR
AND DRY AIR INTRUSIONS SHOULD LEAD TO A SLOW FILLING OF IVONE DURING
NEXT WEEK. IT COULD STILL MAINTAIN GALES IN ITS SOUTHERN PART DUE TO
THE GRADIENT EFFECT.

NO SIGNIFICANT IMPACT IS EXPECTED ON INHABITED LAND.

pocketbox

全球热带气旋监测公报
预报：宋佳凝  签发：张 玲  2025 年 03 月 10 日 10 时
“伊沃娜”向南偏西方向移动

时       间：10日08时（北京时）

海       域：南印度洋

命       名：“伊沃娜”，IVONE

中心位置：南纬17.9度、东经82.9度

强度等级：热带风暴

最大风力：9级（23米/秒，相当于我国的热带风暴级）

中心气压：995百帕

参考位置：毛里求斯路易港偏东方向约2680公里的洋面上

变化过程：过去24小时，“伊沃娜”强度维持不变

预报结论：“伊沃娜”将以每小时20-25公里的速度向南偏西方向移动，强度变化不大。



图3 卫星红外监测图像（北京时间2025年03月10日08时00分）

pocketbox

WTIO30 FMEE 100729
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 9/13/20242025
1.A MODERATE TROPICAL STORM 13 (IVONE)

2.A POSITION 2025/03/10 AT 0600 UTC:
WITHIN 30 NM RADIUS OF POINT 19.5 S / 82.3 E
(NINETEEN    DECIMAL FIVE   DEGREES SOUTH AND
EIGHTY TWO    DECIMAL THREE   DEGREES EAST)
MOVEMENT: SOUTH-SOUTH-WEST 13 KT

3.A DVORAK ANALYSIS: 3.0/3.0/S 0.0/6 H

4.A CENTRAL PRESSURE: 989 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: 500 SE: 610 SW: 500 NW: 295
34 KT NE: 305 SE: 435 SW: 295 NW: 195
48 KT NE: 0 SE: 0 SW: 0 NW: 0
64 KT NE: 0 SE: 0 SW: 0 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1009 HPA / 900 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2025/03/10 18 UTC: 20.4 S / 81.1 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 250 SE: 685 SW: 435 NW: 215
34 KT NE: 130 SE: 435 SW: 285 NW: 120
48 KT NE: 85 SE: 110 SW: 75 NW: 0

24H: 2025/03/11 06 UTC: 20.4 S / 79.1 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 165 SE: 530 SW: 510 NW: 130
34 KT NE: 75 SE: 315 SW: 240 NW: 0

36H: 2025/03/11 18 UTC: 20.2 S / 76.5 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 165 SE: 575 SW: 500 NW: 95
34 KT NE: 75 SE: 345 SW: 220 NW: 0

48H: 2025/03/12 06 UTC: 20.4 S / 73.1 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 185 SE: 405 SW: 315 NW: 100
34 KT NE: 85 SE: 230 SW: 185 NW: 0

60H: 2025/03/12 18 UTC: 20.5 S / 69.9 E, VENT MAX= 030 KT, REMNANT
LOW
28 KT NE: 165 SE: 390 SW: 220 NW: 95

72H: 2025/03/13 06 UTC: 22.3 S / 67.7 E, VENT MAX= 030 KT, REMNANT
LOW
28 KT NE: 260 SE: 370 SW: 185 NW: 130

2.B LONGER-RANGE OUTLOOK:
96H: 2025/03/14 06 UTC: 28.3 S / 66.1 E, VENT MAX= 025 KT,
DISSIPATING

2.C ADDITIONAL INFORMATION:
T=CI=3.0+

WITH LITTLE CHANGE OVER THE LAST 6 HOURS, CONVECTIVE ACTIVITY HAS
REMAINED IN THE SOUTHEAST QUADRANT, WITH COLD SUMMITS. THIS STRUCTURE
IS PROBABLY THE DIRECT CONSEQUENCE OF A NORTHERLY WINDSHEAR,
PARTICULARLY IN THE MID-TROPOSPHERE. THE ASCAT-C OF 0416UTC SHOWS AN
EXPOSED LOW-LEVEL CENTER, VERY ELONGATED IN THE NORTH-SOUTH
DIRECTION, WITH MAXIMUM MEAN WINDS IN THE SOUTHERN SEMICIRCLE, BELOW
THE MAIN CONVECTION. THE DEBIASED MEAN WINDS ARE OF THE ORDER OF
45/50KT, HIGHER THAN THE PRESENT INTENSITY FORECAST. BESTRACK WILL
THEREFORE BE UPDATED SHORTLY IN THE LIGHT OF THIS DIRECT OBSERVATION.

NO CHANGE IN TERMS OF TRACK FORECAST: IVONE IS CURRENTLY MOVING IN A
SOUTH-WESTERLY DIRECTION UNDER THE INFLUENCE OF THE RIDGE TO THE EAST
OF THE SYSTEM. TODAY, THE ARRIVAL OF THE SUBTROPICAL RIDGE TO THE
SOUTH SHOULD FAVOR A CHANGE IN TRAJECTORY TOWARDS THE WEST UNTIL
MID-WEEK. FROM THURSDAY ONWARDS, THE SYSTEM SHOULD MOVE
SOUTH-WESTWARDS, BYPASSING THE RIDGE TO THE NORTH-WEST AND THEN
PLUNGING FURTHER SOUTH.

IN TERMS OF INTENSITY, IVONE WILL REMAIN CLOSE TO CURRENT LEVELS FOR
THE NEXT 12/18H. BEYOND THIS, WESTERLY WINDSHEAR AND INTRUSIONS OF
DRY AIR SHOULD LEAD TO A SLOW FILLING IN OF IVONE OVER THE NEXT 5
DAYS. IT COULD STILL MAINTAIN STRONG WINDS OVER THE NEXT 48 HOURS IN
ITS SOUTHERN PART DUE TO THE GRADIENT EFFECT.

NO SIGNIFICANT IMPACT IS EXPECTED ON INHABITED LAND.