全球热带气旋监测公报

WTIO30 FMEE 040627
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 22/1/20232024
1.A POST-TROPICAL DEPRESSION 1 (ALVARO)

2.A POSITION 2024/01/04 AT 0600 UTC:
WITHIN 20 NM RADIUS OF POINT 27.8 S / 55.6 E
(TWENTY SEVEN    DECIMAL EIGHT   DEGREES SOUTH AND
FIFTY FIVE    DECIMAL SIX   DEGREES EAST)
MOVEMENT: SOUTH-EAST 17 KT

3.A DVORAK ANALYSIS: NIL
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: 335 SE: 405 SW: 295 NW: 240
34 KT NE: 205 SE: 295 SW: 185 NW: 150

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1009 HPA / 800 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2024/01/04 18 UTC: 29.5 S / 58.3 E, VENT MAX= 045 KT,
POST-TROPICAL DEPRESSION
28 KT NE: 335 SE: 465 SW: 335 NW: 280
34 KT NE: 205 SE: 335 SW: 220 NW: 150

24H: 2024/01/05 06 UTC: 30.2 S / 60.4 E, VENT MAX= 035 KT,
POST-TROPICAL DEPRESSION
28 KT NE: 335 SE: 520 SW: 370 NW: 295
34 KT NE: 100 SE: 350 SW: 240 NW: 0

36H: 2024/01/05 18 UTC: 30.2 S / 62.0 E, VENT MAX= 035 KT,
EXTRATROPICAL DEPRESSION
28 KT NE: 0 SE: 480 SW: 390 NW: 0
34 KT NE: 0 SE: 390 SW: 280 NW: 0

48H: 2024/01/06 06 UTC: 30.1 S / 63.4 E, VENT MAX= 030 KT,
EXTRATROPICAL DEPRESSION
28 KT NE: 0 SE: 445 SW: 405 NW: 0

60H: 2024/01/06 18 UTC: 29.5 S / 65.3 E, VENT MAX= 025 KT,
DISSIPATING


2.B LONGER-RANGE OUTLOOK:
NIL


2.C ADDITIONAL INFORMATION:
ALVARO CONTINUES TO DISPLAY A TYPICAL POST-TROPICAL SYSTEM CLOUD
PATTERN, WITH AN EXPOSED CENTER AND DEEP CONVECTION DISPLACED MORE
THAN 100MN TO THE SOUTHEAST OF THE LLCC UNDER THE EFFECT OF STRONG
WIND SHEAR. THE LATEST SMAP PASSES INDICATE STRONGER WINDS THAN
INITIALLY ESTIMATED (43KT YESTERDAY AT 1456Z, 54KT THIS MORNING AT
0151Z) AND SHOW AN ASYMMETRICAL WIND STRUCTURE WITH MAXIMUM WINDS TO
THE SOUTH AND SOUTH-WEST OF THE SYSTEM. THE INTENSITY ESTIMATE HAS
THEREFORE BEEN RAISED TO 45KT, MAKING A COMPROMISE BETWEEN THESE DATA
(WHICH PROBABLY HAVE AN UPWARD BIAS) AND THE BEST MODEL ESTIMATES
(GFS SEEMS BEST ALIGNED WITH CURRENT INTENSITY). THE BEST TRACK HAS
ALSO BEEN REVISED IN LINE WITH THESE DATA. THE INITIAL POSITION IS
STILL RATHER UNCERTAIN DUE TO THE ELONGATED STRUCTURE OF THE CORE.
WATER VAPOR IMAGERY SHOWS AN INTRUSION OF DRY AIR OVER THE CENTER,
CONFIRMING THE ONGOING BAROCLINIC INTERACTION.

ALVARO IS STILL BEING STEERED BY THE MID-LEVEL RIDGE STRENGTHENING
NORTH OF THE MASCARENE ISLANDS. IT FAVOURS A FAST MOVEMENT
SOUTHEASTWARDS AT SHORT RANGE, THEN A SLOWER MOVEMENT EASTWARDS WITH
THE ARRIVAL OF CONTRARY FLOWS SOUTH OF THE SYSTEM BY FRIDAY.

ALVARO IS EXPECTED TO SLIGHTLY RE-STRENGTHEN THIS THURSDAY DUE TO
BAROCLINIC PROCESSES IMPULSED BY THE SUBTROPICAL JETSTREAM DYNAMICS.
THIS INTERACTION SHOULD CEASE FROM FRIDAY ONWARDS, WHICH WILL LEAVE
THE REMNANT LOW SLOWLY FILL UP IN THE FOLLOWING DAYS OVER COOL WATERS
LOCATED NEAR 30S.

THE SYSTEM NO LONGER POSES ANY THREAT TO INHABITED LANDS.=

全球热带气旋监测公报

ABIO10 PGTW 041200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN 
REISSUED/041200Z-041800ZJAN2024//
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: NONE.
   C. SUBTROPICAL SYSTEM SUMMARY:
      (1) AN AREA OF CONVECTION (REMNANTS 04S) HAS PERSISTED NEAR 29.1S 
57.3E, APPROXIMATELY 530 NM SOUTH OF MAURITIUS. THE SYSTEM IS CURRENTLY 
CLASSIFIED AS A SUBTROPICAL CYCLONE, GENERALLY CHARACTERIZED AS HAVING 
BOTH TROPICAL AND MIDLATITUDE CYCLONE FEATURES. ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY AND MICROWAVE IMAGERY DEPICT A BROAD, ASYMMETRIC LOW-
LEVEL CIRCULATION (LLC) BECOMING EMBEDDED IN THE MIDLATITUDE WESTERLIES 
WITH THE MAJORITY OF CONVECTION SHEARED TO THE SOUTHEAST. RECENT 
SCATTEROMETER DATA REVEALS 30-35 KT WINDS SOUTH OF THE LLC. 
ENVIRONMENTAL ANALYSIS INDICATES UNFAVORABLE CONDITIONS FOR TROPICAL 
TRANSITION DEFINED BY STRONG WESTERLIES ALOFT, HIGH (40-50 KTS) VERTICAL 
WIND SHEAR, AND COOL (23-25 C) SEA SURFACE TEMPERATURES. GLOBAL MODELS 
ARE IN GOOD AGREEMENT THAT THE REMNANTS OF 04S WILL TRACK EAST-
SOUTHEASTWARD AS IT GRADUALLY WEAKENS OVER THE NEXT 24-48 HOURS. MAXIMUM 
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 30 TO 35 KNOTS. MINIMUM SEA 
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 996 MB. FOR HAZARDS AND WARNINGS, 
REFERENCE THE FLEET WEATHER SAN DIEGO HIGH WINDS AND SEAS PRODUCT OR 
REFER TO LOCAL WMO DESIGNATED FORECAST AUTHORITY. THE POTENTIAL FOR THE 
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS 
IS LOW.
      (2) NO OTHER SUBTROPICAL SYSTEMS.
3. JUSTIFICATION FOR REISSUE: ADDED AREA IN 2.C.(1) AS A LOW.//
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WTIO30 FMEE 041240
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 23/1/20232024
1.A POST-TROPICAL DEPRESSION 1 (ALVARO)

2.A POSITION 2024/01/04 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 29.0 S / 57.3 E
(TWENTY NINE    DECIMAL ZERO   DEGREES SOUTH AND
FIFTY SEVEN    DECIMAL THREE   DEGREES EAST)
MOVEMENT: SOUTH-EAST 18 KT

3.A DVORAK ANALYSIS: NIL
4.A CENTRAL PRESSURE: 989 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: 370 SE: 480 SW: 315 NW: 280
34 KT NE: 240 SE: 350 SW: 240 NW: 165

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1009 HPA / 800 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2024/01/05 00 UTC: 30.4 S / 60.0 E, VENT MAX= 040 KT,
POST-TROPICAL DEPRESSION
28 KT NE: 390 SE: 500 SW: 350 NW: 280
34 KT NE: 240 SE: 370 SW: 260 NW: 155

24H: 2024/01/05 12 UTC: 30.6 S / 62.2 E, VENT MAX= 035 KT,
POST-TROPICAL DEPRESSION
28 KT NE: 405 SE: 535 SW: 390 NW: 295
34 KT NE: 165 SE: 405 SW: 280 NW: 0

36H: 2024/01/06 00 UTC: 30.4 S / 63.4 E, VENT MAX= 030 KT, FILLING UP
28 KT NE: 0 SE: 535 SW: 405 NW: 0

48H: 2024/01/06 12 UTC: 30.1 S / 64.4 E, VENT MAX= 030 KT, FILLING UP
28 KT NE: 0 SE: 520 SW: 445 NW: 0

60H: 2024/01/07 00 UTC: 29.5 S / 65.1 E, VENT MAX= 025 KT, FILLING UP

72H: 2024/01/07 12 UTC: 28.7 S / 65.5 E, VENT MAX= 025 KT, FILLING UP

2.B LONGER-RANGE OUTLOOK:
NIL


2.C ADDITIONAL INFORMATION:
OVER THE PAST 6 HOURS, POST-TROPICAL DEPRESSION ALVARO HAS KEPT A
TYPICAL ASYMMETRICAL AND HIGHLY SHEARED STRUCTURE, WITH AN EXPOSED
CENTER, DEEP CONVECTION DISPLACED MORE THAN 100MN SOUTHEAST OF THE
CENTER AND A VAST CIRRUS PLUME STRETCHING ALONG THE SUBTROPICAL
WEST-NORTHWESTERLY JETSTREAM'S FLOW. BUOY OBSERVATIONS (ESPECIALLY
989.9HPA ON BUOY 1601656 AT 11UTC VERY CLOSE TO THE CENTER) HAVE
ENABLED TO READJUST THE CENTRAL PRESSURE ESTIMATE TO 989HPA AT 12UTC,
DEEPER THAN INITIALLY ESTIMATED. THIS REFLECTS THE ONGOING BAROCLINIC
INTERACTION, WHICH MAINTAINS A FAIRLY INTENSE VORTEX DESPITE THE
COOLER UNDERLYING WATERS, NEAR 23-24C. MAXIMUM WINDS ARE STILL
ESTIMATED AT 45KT.

ALVARO'S TRACK IS STILL BEING STEERED BY THE RIDGE BUILDING NORTH OF
THE MASCAREIGNES, WHICH FAVORS A RAPID SOUTHEASTWARD MOVEMENT IN THE
SHORT TERM. THIS MOVEMENT WILL SLOW DOWN FROM FRIDAY DUE TO THE
ADDITIONAL CONTRADICTORY INFLUENCE OF A LOW-LEVEL SUBTROPICAL RIDGE
TO THE SOUTH-WEST OF THE SYSTEM. THE RESULTING STEERING FLOW WILL
MAKE THE REMNANT VORTEX SLOWLY DRIFT EASTWARD THEN NORTHEASTWARD BY
THIS WEEKEND, WHILE REMAINING CLOSE TO THE 30TH PARALLEL.

ALVARO HAS TEMPORARILY INTENSIFIED THIS THURSDAY THANKS TO BAROCLINIC
PROCESSES DRIVEN BY THE SUBTROPICAL JETSTREAM DYNAMICS. THIS
INTERACTION SHOULD DECREASE FROM FRIDAY ONWARDS, LEAVING THE REMNANT
LOW SLOWLY FILL UP IN THE FOLLOWING DAYS OVER 22-23 DEGREES SURFACE
WATERS.

THE SYSTEM NO LONGER POSES ANY THREAT TO INHABITED LANDS.


LAST BULLETIN UNLESS RE-INTENSIFICATION ISSUED BY RSMC LA REUNION
REGARDS THIS SYSTEM. FURTHER INFORMATION ON THIS SYSTEM WILL BE
AVAILABLE IN THE DAILY BULLETIN ON TROPICAL WEATHER CONDITIONS OVER
THE SOUTHWEST INDIAN OCEAN ISSUED AT 12Z (AWIO20 FMEE).=

ABIO10 PGTW 051800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN 
OCEAN/051800Z-061800ZJAN2024//
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: NONE.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.//
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