king111807

MFR降格中度熱帶風暴

WTIO30 FMEE 221841
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 22/4/20252026
1.A MODERATE TROPICAL STORM 4 (CHENGE)

2.A POSITION 2025/10/22 AT 1800 UTC:
WITHIN 20 NM RADIUS OF POINT 10.3 S / 60.7 E
(TEN    DECIMAL THREE   DEGREES SOUTH AND
SIXTY    DECIMAL SEVEN   DEGREES EAST)
MOVEMENT: WEST 10 KT

3.A DVORAK ANALYSIS: 2.5/3.5/W 1.0/24 H

4.A CENTRAL PRESSURE: 993 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: 205 SE: 295 SW: 260 NW: 205
34 KT NE: 130 SE: 165 SW: 150 NW: 140

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1009 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2025/10/23 06 UTC: 10.5 S / 58.8 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 185 SE: 305 SW: 260 NW: 165
34 KT NE: 110 SE: 165 SW: 140 NW: 110

24H: 2025/10/23 18 UTC: 10.5 S / 56.9 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 155 SE: 315 SW: 305 NW: 165
34 KT NE: 95 SE: 185 SW: 165 NW: 100

36H: 2025/10/24 06 UTC: 10.2 S / 54.3 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 150 SE: 370 SW: 350 NW: 155
34 KT NE: 0 SE: 220 SW: 195 NW: 95

48H: 2025/10/24 18 UTC: 9.7 S / 51.9 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 140 SE: 380 SW: 370 NW: 165
34 KT NE: 0 SE: 195 SW: 205 NW: 100

60H: 2025/10/25 06 UTC: 9.3 S / 49.4 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 130 SE: 380 SW: 360 NW: 165
34 KT NE: 0 SE: 195 SW: 195 NW: 95

72H: 2025/10/25 18 UTC: 9.0 S / 46.6 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 0 SE: 315 SW: 280 NW: 150
34 KT NE: 0 SE: 165 SW: 140 NW: 0

2.B LONGER-RANGE OUTLOOK:
96H: 2025/10/26 18 UTC: 8.8 S / 40.7 E, VENT MAX= 030 KT, TROPICAL
DEPRESSION
28 KT NE: 0 SE: 240 SW: 205 NW: 0

120H: 2025/10/27 18 UTC: 8.6 S / 36.6 E, VENT MAX= 015 KT,
DISSIPATING

2.C ADDITIONAL INFORMATION:
T=2.5 CI=3.5

OVER THE LAST 6 HOURS, THE SYSTEM'S CLOUD PATTERN HAS CONTINUED TO
DETERIORATE AND CLOUD TOP TEMPERATURES HAVE BEEN WARMING UP.
CONVECTION REMAINS SHIFTED WEST AND NORTHWEST OF THE LOW-LEVEL
CIRCULATION UNDER THE EFFECT OF EAST-NORTHEASTERLY WIND SHEAR.
SUBJECTIVE DVORAK ANALYSIS, BASED ON THE MET AND PT, YIELDS A T
NUMBER DOWN TO 2.5. CI IS LEFT AT 3.5 BY INERTIA, GIVEN THE SYSTEM'S
BROAD SIZE. A 1410Z SAR RCM2 PASS SHOWS 1-MINUTE WINDS GENERALLY
BETWEEN 45 AND 50KT (WITH UNREPRESENTATIVE VERY LOCAL PEAKS AT
55-60KT), SUGGESTING THAT THE SYSTEM'S WINDS WERE ALREADY PROBABLY
BELOW 50KT (10-MINUTE WINDS) AT 12UTC. THE 1714Z ASCAT-C PASS
CONFIRMS THIS WEAKENING TREND, WITH WINDS MEASURED AT ONLY 37KT,
EQUIVALENT TO 40KT TAKING INTO ACCOUNT ASCAT'S UNDERESTIMATION. THE
SYSTEM'S INTENSITY IS THEREFORE DOWNGRADED TO 40KT AT 18UTC, SLIGHTLY
BELOW DVORAK ANALYSIS AND MOST CIMSS OBJECTIVE ESTIMATES AND FAIRLY
CONSISTENT WITH IFS AND AROME MODEL ANALYSES, WHILE GFS TENDS TO
OVERESTIMATE THE CURRENT INTENSITY. THE 12UTC ANALYSIS INTENSITY HAS
ALSO BEEN CORRECTED TO 45KT INSTEAD OF 50KT IN THE BEST TRACK.
ACCORDING TO RECENT ASCAT DATA, THE POSITION OF THE CENTER IS
SLIGHTLY NORTH OF WHAT PREVIOUS RSMC FORECASTS HAD PREDICTED.

THE FORECAST TRACK HAS BEEN SLIGHTLY SHIFTED NORTHWARD IN THE SHORT
TERM TO TAKE INTO ACCOUNT THE NORTHWARD SHIFT IN THE ANALYSED
POSITION AND FOLLOWING MODELS THAT ARE FITTING BETTER WITH RECENT
OBSERVATIONS. THE SYSTEM IS MOVING WESTWARDS AND STARTING TO
ACCELERATE UNDER THE INFLUENCE OF THE STEERING FLOW IMPOSED BY THE
LOW-LEVEL AND MID-LEVEL SUBTROPICAL HIGH LOCATED TO THE SOUTH.
UNCERTAINTIES REMAIN FOR THE END OF THE WEEK, PARTICULARLY CONCERNING
A MORE OR LESS WEST-NORTHWESTWARD SHIFT, WHICH WOULD BE MORE MARKED
IN THE EVENT OF A FASTER WEAKENING SYSTEM. THE FORECAST TRACK IS A
COMPROMISE BETWEEN VARIOUS AVAILABLE NWP OUTPUT. THE SYSTEM WILL
TRACK NEAR AGALEGA DURING THE NIGHT FROM THURSDAY TO FRIDAY AND
FARQUHAR ISLANDS DURING THE NIGHT FROM FRIDAY TO SATURDAY, THEN NEAR
ASTOVE AND ALDABRA ON SATURDAY EVENING.

THE SYSTEM'S INTENSITY IS EXPECTED TO REMAIN AT MODERATE TROPICAL
STORM STAGE IN THE SHORT TERM, BUT WITH POSSIBLE SMALL VARIATIONS.
ENVIRONMENTAL UNFAVORABLE FACTORS (MODERATE SHEAR AND DRY AIR
INTRUSIONS) MAY BE PARTIALLY OFFSET BY THE ACCELERATION OF THE
MOVEMENT, MORE OR LESS ENABLING THE EFFECTS OF SHEAR TO REMAIN
LIMITED. THERE IS STILL SIGNIFICANT DISPERSION IN THE RATE OF
WEAKENING BETWEEN NOW AND SATURDAY, WITH SOME MODELS EVEN SUGGESTING
SLIGHT TEMPORARY RE-INTENSIFICATIONS (PARTICULARLY IF IT MOVES FASTER
AND SOUTH OF THE CURRENTLY FORECAST TRACK). WEAKENING SHOULD BE MORE
SIGNIFICANT AT THE END OF THE FORECAST PERIOD AS IT APPROACHES THE
AFRICAN COAST.

EXPECTED IMPACTS ON LAND OVER THE NEXT 72 HOURS:
- AGALEGA: GALE-FORCE WINDS LIKELY AND HEAVY RAINFALL OF 100 TO 150
MM IN 24 HOURS BETWEEN THURSDAY AND FRIDAY. WAVES OF 4 TO 6 METRES
FROM THURSDAY THROUGH FRIDAY MORNING.
- FARQUHAR: POSSIBLE GALE-FORCE WINDS AND HEAVY SHOWERS OF LESS THAN
100MM IN 24 HOURS FROM FRIDAY EVENING. WAVES OF 4 TO 6 METRES FROM
FRIDAY THROUGH SATURDAY.
- NORTH OF ANTSIRANANA PROVINCE (MADAGASCAR): LOW PROBABILITY OF
GALE-FORCE WINDS, HEAVY RAINFALL OF LESS THAN 100MM IN 24 HOURS ON
FRIDAY NIGHT AND SATURDAY. WAVES OF 4 TO 6 METRES EXPECTED FROM
FRIDAY EVENING.
- ASTOVE/ALDABRA: HEAVY SHOWERS OF LESS THAN 100MM IN 24 HOURS AND
WAVES OF 4 TO 6 METRES EXPECTED FROM SATURDAY.=

king111807

MFR降格TD，並發出最終報

WTIO30 FMEE 250013
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 31/4/20252026
1.A TROPICAL DEPRESSION 4 (CHENGE)

2.A POSITION 2025/10/25 AT 0000 UTC:
WITHIN 20 NM RADIUS OF POINT 8.3 S / 52.7 E
(EIGHT DECIMAL THREE DEGREES SOUTH AND
FIFTY TWO DECIMAL SEVEN DEGREES EAST)
MOVEMENT: WEST-NORTH-WEST 10 KT

3.A DVORAK ANALYSIS: 2.0/2.5/W 0.5/6 H

4.A CENTRAL PRESSURE: 1000 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 315 SW: 370 NW: 205

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): NIL
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2025/10/25 12 UTC: 7.6 S / 50.7 E, VENT MAX= 030 KT, TROPICAL DEPRESSION
28 KT NE: 0 SE: 285 SW: 285 NW: 0

24H: 2025/10/26 00 UTC: 7.1 S / 49.2 E, VENT MAX= 030 KT, TROPICAL DEPRESSION
28 KT NE: 0 SE: 285 SW: 285 NW: 0

36H: 2025/10/26 12 UTC: 6.6 S / 47.5 E, VENT MAX= 030 KT, TROPICAL DEPRESSION
28 KT NE: 0 SE: 285 SW: 285 NW: 0

48H: 2025/10/27 00 UTC: 6.3 S / 45.4 E, VENT MAX= 025 KT, REMNANT LOW

60H: 2025/10/27 12 UTC: 5.9 S / 42.7 E, VENT MAX= 025 KT, REMNANT LOW

72H: 2025/10/28 00 UTC: 4.9 S / 40.4 E, VENT MAX= 020 KT, REMNANT LOW

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
T=2.0 CI=2.5

OVER THE LAST 6 HOURS, CONVECTIVE ACTIVITY HAS WEAKENED IN THE
WESTERN SEMICIRCLE. THE SYSTEM REMAINS IN A STRONGLY SHEAR PATTERN, AS
SHOWN BY THE GCOM-W MICROWAVE IMAGE AT 2236Z. THE LATEST ASCAT PASS AT
1812Z DID NOT ALLOW DIRECT MEASUREMENT OF MAXIMUM WINDS NEAR THE
CENTER OF THE SYSTEM. HOWEVER, IT SUGGESTS THAT AREAS OF WINDS ABOVE
34 KT WOULD BE RESIDUAL. SUBJECTIVE AND OBJECTIVE DVORAK ANALYSES
ALSO SHOW A DOWNWARD TREND. CHENGE IS THEREFORE DOWNGRADED TO A
TROPICAL DEPRESSION WITH MAXIMUM WINDS ESTIMATED AT 30 KT.

IN TERMS OF TRAJECTORY, THERE IS LITTLE CHANGE FROM THE PREVIOUS
FORECAST. CHENGE IS MOVING WEST-NORTHWESTWARDS UNDER THE INFLUENCE
OF THE STEERING FLOW IMPOSED BY THE SUBTROPICAL RIDGE IN THE LOWER TO
MID TROPOSPHERE LOCATED FURTHER SOUTH. THE SYSTEM IS EXPECTED TO PASS
NORTH OF FARQUHAR ON SATURDAY, THEN NORTH OF ASTOVE AND ALDABRA ON
SUNDAY. IN TERMS OF MODELS, THERE ARE STILL DIFFERENCES IN MOVEMENT
SPEEDS, PARTICULARLY AT SHORT RANGE.

IN TERMS OF INTENSITY, UNDER THE EFFECT OF STRONG EAST-NORTHEASTERLY
SHEAR, THE SYSTEM IS EXPECTED TO KEEP WEAKENING OVER THE NEXT 48 HOURS
AND EVOLVE INTO A RESIDUAL DEPRESSION NORTH OF THE MOZAMBIQUE
CHANNEL. CHENGE IS EXPECTED TO CLOSE IN ON THE TANZANIAN AND KENYAN
COASTS.

EXPECTED IMPACTS ON LAND OVER THE NEXT 72 HOURS:
- FARQUHAR: GALE-FORCE WINDS AND HEAVY SHOWERS POSSIBLE, WITH
ACCUMULATIONS OF 50MM IN 24 HOURS BETWEEN FRIDAY EVENING AND
SATURDAY EVENING. WAVES OF 4 TO 6 METERS OVER THE SAME PERIOD.
- NORTH OF ANTSIRANANA PROVINCE (MADAGASCAR): MILD DETERIORATION, 4M
WAVES
- ASTOVE/ALDABRA: HEAVY RAIN POSSIBLE, 4M WAVES.
- TANZANIAN COAST: HEAVY RAIN POSSIBLE ON MONDAY, WITH UP TO 50MM IN 24
HOURS IN HIGHER TERRAIN.

king111807

JTWC發布FW

WTXS31 PGTW 252100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 04S (CHENGE) WARNING NR 020//
RMKS/
1. TROPICAL CYCLONE 04S (CHENGE) WARNING NR 020   
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   251800Z --- NEAR 8.1S 49.9E
     MOVEMENT PAST SIX HOURS - 260 DEGREES AT 06 KTS
     POSITION ACCURATE TO WITHIN 020 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   REPEAT POSIT: 8.1S 49.9E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   260600Z --- 7.7S 48.2E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
252100Z POSITION NEAR 8.0S 49.5E.
25OCT25. TROPICAL CYCLONE (TC) 04S (CHENGE), LOCATED APPROXIMATELY
635 NM EAST OF DAR ES SALAAM, TANZANIA, HAS TRACKED WESTWARD AT 06
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL IMAGERY
REVEALS A SHALLOW AND FULLY EXPOSED LOW-LEVEL CIRCULATION CENTER
AS DEEP CONVECTION HAS COMPLETELY COLLAPSED OVER THE LAST 12
HOURS. THE CURRENT ENVIRONMENT IS HIGHLY UNFAVORABLE WITH VERTICAL
WIND SHEAR ABOVE 30KTS AND STRAIGHT-LINE FLOW ALOFT. OVER THE NEXT
12 HOURS, THE REMNANTS OF TC 04S WILL CONTINUE TO DRIFT WEST-
NORTHWESTWARD AS THE SYSTEM CONTINUES TO WEAKEN IN AN ADVERSE
ENVIRONMENT. DETERMINISTIC MODEL GUIDANCE IS SUPPORTIVE OF THE
TRACK AND IS IN STRONG LINEAR AGREEMENT. THE INTENSITY GUIDANCE
VARIES SLIGHTLY BETWEEN STAGNATION AT 30KTS OVER THE NEXT 12 HOURS
OR CONTINUED WEAKENING. EITHER WAY, THE GUIDANCE DOES NOT INDICATE
RE-INTENSIFICATION. THIS IS THE FINAL WARNING ON THIS SYSTEM BY
THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE
CLOSELY MONITORED FOR SIGNS OF REGENERATION. MINIMUM CENTRAL
PRESSURE AT 251800Z IS 1003 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
251800Z IS 12 FEET.//
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