WEATHER BULLETIN FOR THE HIGH SEAS FOR METAREA VII.
ISSUED BY THE SOUTH AFRICAN WEATHER SERVICE ON THE
17TH OF JANUARY 2025 AT 17:00 UTC.
FOR SOUTH-EAST SECTOR OF METAREA. VII, PREPARED BY REUNION, SEE AREA 2
BELOW.
NOTE: WX OBSERVATIONS.
======================
COULD ALL VESSELS EXPERIENCING UNEXPECTED, SEVERE WX/SEA STATE PLEASE
MAKE EVERY EFFORT TO REPORT THIS TO SAWS VIA CAPE TOWN RADIO.
AREA 1:
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FORECAST VALID FROM 172200 TO 182200 UTC:
WIND IN KNOTS, WAVE HEIGHTS IN METERS. NO SEA STATE GIVEN IF WAVES LESS THAN 3M.
NOTE THE WIND SPEEDS QUOTED HERE ARE THE EXPECTED AVERAGE SPEEDS.
INDIVIDUAL GUSTS MAY EXCEED THESE VALUES BY A FACTOR OF UP TO 1.5.
WAVE HEIGHTS ARE SIGNIFICANT WAVE HEIGHTS, WHICH MAY BE ACCOMPANIED BY INDIVIDUAL WAVES 1.5 TO 2.0 TIMES HIGHER.
RSMC / TROPICAL CYCLONE CENTER / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 43/5/20242025
1.A POST-TROPICAL DEPRESSION 5 (DIKELEDI)
2.A POSITION 2025/01/17 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 34.6 S / 58.5 E
(THIRTY-FOUR DECIMAL SIX DEGREES SOUTH AND FIFTY-EIGHT DECIMAL FIVE
DEGREES EAST)
MOVEMENT: EAST-SOUTH-EAST 31 KT
3.A DVORAK ANALYSIS: NIL
4.A CENTRAL PRESSURE: 988 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 55 KT RADIUS OF MAXIMUM WINDS (RMW): NIL
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 295 SE: 165 SW: 140 NW: 270
34 KT NE: 215 SE: 120 SW: 110 NW: 165
48 KT NE: 130 SE: 0 SW: 80 NW: 130
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 500 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM
1.B FORECASTS (WINDS RADII IN KM):
12H: 2025/01/18 00 UTC: 34.9 S / 64.9 E, WIND MAX= 045 KT, POST-TROPICAL DEPRESSION
28 KT NE: 285 SE: 0 SW: 195 NW: 295
34 KT NE: 185 SE: 0 SW: 85 NW: 155
24H: 2025/01/18 12 UTC: 34.4 S / 71.8 E, WIND MAX= 035 KT, EXTRATROPICAL DEPRESSION
28 KT NE: 230 SE: 0 SW: 220 NW: 260
34 KT NE: 140 SE: 0 SW: 85 NW: 110
36H: 2025/01/19 00 UTC: 34.1 S / 76.5 E, WIND MAX= 030 KT, EXTRATROPICAL DEPRESSION
28 KT NE: 0 SE: 150 SW: 150 NW: 195
48H: 2025/01/19 12 UTC: 34.2 S / 80.6 E, WIND MAX= 030 KT, EXTRATROPICAL DEPRESSION
28 KT NE: 0 SE: 185 SW: 130 NW: 140
GALE FORCE WARNINGS:
====================
1. MARION FORTIES EAST: W to NW 35 to 40 in the south-west towards mid-
period, spreading over the southern half towards
end of period.
SYNOPTIC CHART 12:00Z
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High 1018 hPa 32s06e, High 1019 hPa 34s36e
Low 988 hPa 48s11e
Low 988 hPa 35s56e (POST-TROPICAL DEPRESSION 5 DIKELEDI)
1. Cold Front: 27s20w 35s04w 40s03e into 48s11e
AREA FORECAST:
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ASCENSION (06S/15S, 00E/20W):
WIND : SE to E 05 to 15.
VIS : Good, but moderate in showers and rain in the north-west.
ANGOLA (06S/15S, 00E/00N):
WIND : S to SE 05 to 15, but SW to W 05 to 10 in the east.
VIS : Good, but moderate to poor in showers and thundershowers in
the north and east.
ST HELENA (15S/30S, 00E/20W):
WIND : Variable 05 to 10 in the central parts, otherwise E to SE 05
to 15 but N to NW 15 to 20 in the south-east.
VIS : Moderate in showers and rain in places.
TRADES (15S/30S, 00E/WEST COAST):
WIND : S to SE 10 to 20, but variable 05 to 10 in the south-west.
VIS : Good.
TRISTAN (30S/40S, 00E/20W):
WIND : NW 15 to 25 in the north-east, otherwise W to SW 10 to 20
reaching 25 in the south, but SE to S 10 to 20 in the north-
west. It will become variable 05 to 10 in the west towards end
of period.
VIS : Moderate in showers and rain in places, becoming good from the
south-west towards mid-period.
SEA STATE: 3.0 to 3.5m in the south-east at first, with SW swell.
CAPE WEST (30S/40S, 00E/20E):
WIND : Variable 05 to 10 in the north until mid-period, otherwise NW
10 to 20 reaching 25 to 30 in the south-east, but SW 10 to 20
in the north-east, reaching 25 in the west.
VIS : Good, but moderate in showers and rain in the south-west,
spreading to the north-west and south-east by mid-period.
SEA STATE: 3.0 to 4.0m in the southern half, reaching 4.5m in the south-
east, with SW swell.
CAPE EAST (32.5S/40S, 20E/50E):
WIND : S to SE 10 to 20 in the north-east, otherwise W to NW 10 to
20, reaching 25 in the south-west, but E to NE 15 to 25 in
the north-west. It will become W to SW 10 to 20 in the extreme
north-west by mid-period.
VIS : Moderate in showers, but good in the north and west.
SEA STATE: 3.0 to 3.5m, with SW swell, but with NW swell in the south-
east at first.
DURBAN EAST (32.5S/25S, EAST COAST/55E):
WIND : NW 05 to 15 in the north-east, otherwise S to SE 15 to 25 but
E to NE 15 to 25 in the west.
VIS : Moderate to poor in showers and rain, but good in the south
and west.
SEA STATE: 3.0m in the central and eastern parts, with S to SW swell.
MOZAMBIQUE CHANNEL:
WIND : N to NE 05 to 15 in the north-west, otherwise S to SE 10 to 20
reaching 25 in the south-east, but variable 05 to 10 in the
north-east.
VIS : Moderate to poor in showers and thundershowers in places.
SEA STATE: 3.0m in the south at first, with S to SW swell.
MADAGASCAR EAST (10S/25S, EAST COAST/55E):
WIND : NW 05 to 15 in the south-east, otherwise SE to E 05 to 15, but
NE to N 10 to 20 in the south, and Cyclonic 05 to 15 in the
north.
VIS : Moderate to poor in showers and thundershowers.
MARION FORTIES EAST (40S/50S, 35E/50E):
WIND : SW 10 to 20 in the north-east, otherwise W to NW 15 to 25
reaching 30 to 40 in the south-west towards mid-period,
spreading over the southern half towards end of period.
VIS : Good, but moderate in showers and rain in the north-west and
south-west towards mid-period, spreading to the eastern parts
towards end of period.
SEA STATE: 3.5 to 4.5m, reaching 5.0 to 6.0m in the south and south-west,
with W to SW swell.
AREA 2:
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MARINE METEOROLOGICAL BULLETIN FROM METEO-FRANCE/LA REUNION ON AREA ACK (AMSTERDAM-CROZET-KERGUELEN)
25/01/17 AT 1700UTC
AVERAGED WIND SPEED ON BEAUFORT SCALE. (WIND GUSTS MAY BE ABOUT 40%
STRONGER THAN THE AVERAGES GIVEN HERE).
PART 1: WARNING
- GALE FORCE 8 EXPECTED OVER WESTERN AREA OF AMS.
- STRONG GALE FORCE 9 OVER EASTERN WAM ASSOCIATED WITH POST-TROPICAL
DEPRESSION EX-DIKELEDI.
PART 2: GENERAL SYNOPSIS, 25/01/17 AT 1200UTC
- POST-TROPICAL DEPRESSION EX-DIKELEDI 988 HPA NEAR 34.6S/58.5E,
MOVING EAST-SOUTHEASTWARD AT 30 KT AND FILLING. FORECAST 1003 HPA
NEAR 35S/76E AT END.
- ASSOCIATED COLD FRONT AXIS 26S/49E, 31S/57E, 35S/59E AND WARM FRONT
AXIS 40S/68E 39S/63E 35S/59E MOVING WITH THE LOW.
- COLD FRONT OVER NORTHERN KER AND FAR SOUTHERN AMS LEAVING THE AREA SOON.
- HIGH 1020 HPA FORECAST OVER WAM
PART 3: FORECAST FOR 24 HOURS FROM 25/01/17 AT 1800UTC TO 25/01/18
AT 1800UTC
WAM (30S/40S, 50E/65E)
FRONTAL RAIN AND SHOWERS, SQUALLY WEATHER WITHIN A 200 NM RADIUS OF
EX-DIKELEDI CENTER.
WIND : CLOCKWISE 7/8 LOCALLY 9 WITH VIOLENT GUSTS NEAR EX-DIKELEDI
TONIGHT. DECREASING SOUTHERLY 5 TO 6 BEHIND AND BECOMING
ANTICLOCKWISE 3 TO 5 LATER.
SEA : ROUGH TO VERY ROUGH, TEMPORARY HIGH NEAR EX-DIKELEDI AT START,
BECOMING MODERATE TO ROUGH AT END. NW SWELL 4 TO 6M NEAR THE
LOW,DECREASING BY WESTERN.
VISI : POOR TO VERY POOR UNDER PRECIPITATION.
AMS (30S/40S, 65E/80E)
FRONTAL RAIN AND SHOWERS, SQUALLY WEATHER WITHIN A 200 NM RADIUS OF
EX-DIKELEDI CENTER.
WIND : NW 5 TO 6 TEMPORARY 7 OVER SOUTHEASTERN AT START. BECOMING
CLOCKWISE 7 TO 8 BY WESTERN TONIGHT, DECREASING 5 TO 6 AT END.
SEA : MODERATE TO ROUGH LOCALLY VERY ROUGH NEAR THE LOW WITH WESTERLY
SWELL 4 TO 5 M DECREASING NEAR 3 M AT END.
VISI : POOR TO VERY POOR UNDER PRECIPITATION.
CRO (40S/50S, 50E/65E)
SCATTERED SHOWERS. FRONTAL RAIN AND SHOWERS OVER FAR SOUTHWESTERN AT END.
WIND : WESTERLY 5 TO 6 LOCALLY 7 OVER SOUTHERN..
SEA : ROUGH TO VERY ROUGH. W SWELL 3 TO 4M.
VISI : POOR UNDER PRECIPITATION.
KER (40S/50S, 65E/80E)
RAIN, SQUALLS AND FRONTAL SHOWERS OVER FAR NORTHERN AT START, LEAVING
THE AREA SOON.
WIND : NW 5 TO 6 OVER FAR NORTHEASTERN, VARIABLE 2/4 ELSWHERE,
INCREASING WESTERLY 5/6 SOON.
SEA : MODERATE TO ROUGH BECOMING VERY ROUGH OVER WESTERN LATER WITH
WESTERLY SWELL 3 TO 4 M.
VISI : POOR TO VERY POOR UNDER PRECIPITATION.