The BoM's Tropical Low 27U has been designated Invest 92S by the JTWC now.
| SH, 92, 2025032100, , BEST, 0, 154S, 1121E, 15, 1009, DB, 0, |
-
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2025 Global Tropical Cyclone Season Discussion
- Thread starter Atlantic
- Start date
For SHEM ACE we are now closing in on the 2024-25 season moving up one more place again:
1996-97 = 358.4
1991-92 = 318.2
1993-94 = 317.6
2018-19 = 282.9
1988-89 = 269.5
2002-03 = 262.5
2004-05 = 259.5
1997-98 = 258.4
1995-96 = 235.4
1979-80 = 231.1
2022-23 = 231.0
1992-93 = 227.4
2003-04 = 226.2
1999-2000 = 224.6
2024-25 = 221.0 (current)
1998-99 = 213.2
2015-16 = 209.3
1989-90 = 206.4
2014-15 = 205.2
1984-85 = 202.6
1996-97 = 358.4
1991-92 = 318.2
1993-94 = 317.6
2018-19 = 282.9
1988-89 = 269.5
2002-03 = 262.5
2004-05 = 259.5
1997-98 = 258.4
1995-96 = 235.4
1979-80 = 231.1
2022-23 = 231.0
1992-93 = 227.4
2003-04 = 226.2
1999-2000 = 224.6
2024-25 = 221.0 (current)
1998-99 = 213.2
2015-16 = 209.3
1989-90 = 206.4
2014-15 = 205.2
1984-85 = 202.6
- Messages
- 2,828
- Location
- Smithville MS
We are now at 82 consecutive days without the first tropical system of 2025 in the Western Pacific. There's only 4 years that went over 100 days without the first tropical system: 1983 at 174, 1984 at 158, 1998 at 187 (most consecutive days on record), and 2024 at 142. I know the JMA noted a TD in February, but JTWC didn't initiate advisories on it. @Atlantic
The JTWC is watching an Invest 96W right now, but I highly doubt it will amount to much. So the streak will likely continue into April.
Invest 92S (Tropical Low 27U) hasn't formed yet, but it is still a high chance Invest per the JTWC. The BoM number and the JTWC number will coincide if 92S forms as it will be 27S\27U.
We also have another signal in the western AU, which could potentially strike western Australia, and affect the same areas that were hit by Severe Tropical Cyclone Zelia in February. If the system formed, the GFS at least expects the system to move WSW towards Western Australia.
We also have another signal in the western AU, which could potentially strike western Australia, and affect the same areas that were hit by Severe Tropical Cyclone Zelia in February. If the system formed, the GFS at least expects the system to move WSW towards Western Australia.
And we now have Tropical Cyclone 27S!
Tropical Storm TWENTYSEVE
Updated March 24, 2025 at 12:00 UTC
Located at 16.6°S, 111°E
Minimum Pressure: 995 mb
Maximum Winds: 35 kt
Radius of Maximum Wind: 35 nm
Environmental Pressure: 1004 mb
Storm Radius: 200 nm
Formerly Invest 92S
Satellite LoopRadar LoopLatest GFS ForecastLatest ECMWF Forecast
Tropical Storm TWENTYSEVE
Updated March 24, 2025 at 12:00 UTC
Located at 16.6°S, 111°E
Minimum Pressure: 995 mb
Maximum Winds: 35 kt
Radius of Maximum Wind: 35 nm
Environmental Pressure: 1004 mb
Storm Radius: 200 nm
Formerly Invest 92S
Satellite LoopRadar LoopLatest GFS ForecastLatest ECMWF Forecast
Attachments
27S (Twenty-Seven) First Warning:
WTXS31 PGTW 241500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 001//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/232151ZMAR2025//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 001
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
241200Z --- NEAR 16.6S 111.0E
MOVEMENT PAST SIX HOURS - 240 DEGREES AT 11 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
000 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
REPEAT POSIT: 16.6S 111.0E
---
FORECASTS:
12 HRS, VALID AT:
250000Z --- 17.0S 109.4E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 260 DEG/ 06 KTS
---
24 HRS, VALID AT:
251200Z --- 17.2S 108.2E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 260 DEG/ 07 KTS
---
36 HRS, VALID AT:
260000Z --- 17.5S 106.7E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 265 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
261200Z --- 17.6S 104.7E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 270 DEG/ 10 KTS
---
72 HRS, VALID AT:
271200Z --- 17.5S 100.7E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 000 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
130 NM SOUTHEAST QUADRANT
140 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 270 DEG/ 11 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
281200Z --- 17.6S 96.2E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
150 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 120 HR POSIT: 255 DEG/ 11 KTS
---
120 HRS, VALID AT:
291200Z --- 18.8S 91.6E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
150 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
---
REMARKS:
241500Z POSITION NEAR 16.7S 110.6E.
24MAR25. TROPICAL CYCLONE 27S (TWENTYSEVEN), LOCATED
APPROXIMATELY 384 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS
TRACKED WEST-SOUTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS.
MINIMUM CENTRAL PRESSURE AT 241200Z IS 995 MB. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 241200Z IS 18 FEET. NEXT WARNINGS AT
242100Z, 250300Z, 250900Z AND 251500Z.
2. THIS CANCELS AND SUPERSEDES REF A (WTXS21 PGTW 232200).//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 001//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/232151ZMAR2025//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 001
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
241200Z --- NEAR 16.6S 111.0E
MOVEMENT PAST SIX HOURS - 240 DEGREES AT 11 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
000 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
REPEAT POSIT: 16.6S 111.0E
---
FORECASTS:
12 HRS, VALID AT:
250000Z --- 17.0S 109.4E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 260 DEG/ 06 KTS
---
24 HRS, VALID AT:
251200Z --- 17.2S 108.2E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 260 DEG/ 07 KTS
---
36 HRS, VALID AT:
260000Z --- 17.5S 106.7E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 265 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
261200Z --- 17.6S 104.7E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 270 DEG/ 10 KTS
---
72 HRS, VALID AT:
271200Z --- 17.5S 100.7E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 000 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
130 NM SOUTHEAST QUADRANT
140 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 270 DEG/ 11 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
281200Z --- 17.6S 96.2E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
150 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 120 HR POSIT: 255 DEG/ 11 KTS
---
120 HRS, VALID AT:
291200Z --- 18.8S 91.6E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
150 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
---
REMARKS:
241500Z POSITION NEAR 16.7S 110.6E.
24MAR25. TROPICAL CYCLONE 27S (TWENTYSEVEN), LOCATED
APPROXIMATELY 384 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS
TRACKED WEST-SOUTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS.
MINIMUM CENTRAL PRESSURE AT 241200Z IS 995 MB. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 241200Z IS 18 FEET. NEXT WARNINGS AT
242100Z, 250300Z, 250900Z AND 251500Z.
2. THIS CANCELS AND SUPERSEDES REF A (WTXS21 PGTW 232200).//
NNNN
With the recent designation of 27S, the 2024-25 season retains a tied 5th place.
| 1996-97 - 33 | ||
| 1984-85 - 31 | ||
| 1983-84, 1997-98, 1998-99 - 30 | ||
| 1974-75, 1977-78 - 28 | ||
| 1991-92, 2024-25 - 27 | ||
| 1985-86, 1989-90, 2007-08 - 26 | ||
| 1993-94, 2002-03, 2020-21 - 25 | ||
| 1979-80, 1980-81, 1981-82, 1985-86, 2004-05, 2008-09 - 24 | ||
| 1976-77, 1992-93, 1995-96, 2002-03, 2019-20 - 23 | ||
| 1978-79, 1986-87, 1989-90, 2018-19 - 22 |
ACE-wise, the 2024-25 season is still at 15th place with the ACE still unchanged from the last time I posted the ACE ranks.
1996-97 = 358.4
1991-92 = 318.2
1993-94 = 317.6
2018-19 = 282.9
1988-89 = 269.5
2002-03 = 262.5
2004-05 = 259.5
1997-98 = 258.4
1995-96 = 235.4
1979-80 = 231.1
2022-23 = 231.0
1992-93 = 227.4
2003-04 = 226.2
1999-2000 = 224.6
2024-25 = 221.0 (current)
1998-99 = 213.2
2015-16 = 209.3
1989-90 = 206.4
2014-15 = 205.2
1984-85 = 202.6
1996-97 = 358.4
1991-92 = 318.2
1993-94 = 317.6
2018-19 = 282.9
1988-89 = 269.5
2002-03 = 262.5
2004-05 = 259.5
1997-98 = 258.4
1995-96 = 235.4
1979-80 = 231.1
2022-23 = 231.0
1992-93 = 227.4
2003-04 = 226.2
1999-2000 = 224.6
2024-25 = 221.0 (current)
1998-99 = 213.2
2015-16 = 209.3
1989-90 = 206.4
2014-15 = 205.2
1984-85 = 202.6
From BoM on Tropical Low 27U (JTWC's Tropical Cyclone 27S):
IDW24000
Australian Bureau of Meteorology
Tropical Cyclone Warning Centre
TROPICAL CYCLONE INFORMATION BULLETIN
Issued at 2:50 am WST on Tuesday 25 March 2025
A Tropical Low was located at 2:00 am AWST near 16.5S 110.7E,that is 700 km
north northwest of Exmouth and 860 km southeast of Christmas Island and moving
west southwest at 14 kilometres per hour.
Tropical low 27U is located well to the northwest of the Pilbara coast and is
expected to continue to move westwards away from the Australian mainland. 27U
is only slowly developing and it is forecast to intensify into a tropical
cyclone late Wednesday or early Thursday while continuing to move westwards.
It will not impact the Western Australian coast, the Cocos (Keeling) Islands or
Christmas Island.
The next Information Bulletin will be issued at 9:00 am AWST Tuesday 25 March.
IDW24000
Australian Bureau of Meteorology
Tropical Cyclone Warning Centre
TROPICAL CYCLONE INFORMATION BULLETIN
Issued at 2:50 am WST on Tuesday 25 March 2025
A Tropical Low was located at 2:00 am AWST near 16.5S 110.7E,that is 700 km
north northwest of Exmouth and 860 km southeast of Christmas Island and moving
west southwest at 14 kilometres per hour.
Tropical low 27U is located well to the northwest of the Pilbara coast and is
expected to continue to move westwards away from the Australian mainland. 27U
is only slowly developing and it is forecast to intensify into a tropical
cyclone late Wednesday or early Thursday while continuing to move westwards.
It will not impact the Western Australian coast, the Cocos (Keeling) Islands or
Christmas Island.
The next Information Bulletin will be issued at 9:00 am AWST Tuesday 25 March.
More from BoM on 27U/27S:
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1904 UTC 24/03/2025
Name: Tropical Low
Identifier: 27U
Data At: 1800 UTC
Latitude: 16.5S
Longitude: 110.7E
Location Accuracy: within 30nm (55 km)
Movement Towards: west southwest (251 deg)
Speed of Movement: 8 knots (14 km/h)
Maximum 10-Minute Wind: 40 knots (75 km/h)
Maximum 3-Second Wind Gust: 55 knots (100 km/h)
Central Pressure: 994 hPa
Radius of 34-knot winds NE quadrant: 20 nm (35 km)
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant: 40 nm (75 km)
Radius of 48-knot winds NE quadrant:
Radius of 48-knot winds SE quadrant:
Radius of 48-knot winds SW quadrant:
Radius of 48-knot winds NW quadrant:
Radius of 64-knot winds: nm ( km)
Radius of Maximum Winds: nm ( km)
Dvorak Intensity Code: T2.0/2.0/D1.0/24HRS STT
0.5/06HRS
Pressure of outermost isobar: 1004 hPa
Radius of outermost closed isobar: 170 nm (315 km)
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
(UTC) : degrees : nm (km): knots(km/h): hPa
+06: 25/0000: 16.5S 110.2E: 040 (080): 045 (085): 990
+12: 25/0600: 16.6S 109.7E: 050 (090): 040 (075): 993
+18: 25/1200: 16.7S 109.1E: 060 (110): 040 (075): 993
+24: 25/1800: 16.9S 108.4E: 065 (120): 040 (075): 994
+36: 26/0600: 17.3S 106.6E: 085 (155): 040 (075): 994
+48: 26/1800: 17.2S 104.6E: 105 (190): 045 (085): 991
+60: 27/0600: 17.1S 102.5E: 120 (220): 045 (085): 992
+72: 27/1800: 16.8S 100.4E: 120 (225): 045 (085): 991
+96: 28/1800: 17.0S 95.7E: 165 (300): 060 (110): 982
+120: 29/1800: 18.3S 91.6E: 205 (380): 070 (130): 971
REMARKS:
Tropical Low 27U lies well to the northwest of Western Australia and is
forecast to slowly develop as it tracks westwards over the Indian Ocean.
The system was located using animated satellite imagery and an ASCAT-B pass at
1421UTC. The low level centre continues to be covered by cirrus blow off.
Confidence is moderate in the location.
Dvorak analysis based on both a shear pattern yielding a 3-hourly average DT of
2.5, however there is no tight gradient, so this is unreliable. The 24 trend is
D- which gives MET of 2.0, no adj so PAT is also 2.0, FT biased to PAT. FT/CI
is 2.0. Objective aids (all 1 min mean) at 1730UTC are ADT 35 kn, AiDT 34 kn,
DPRINT 36 kn, SATCON 41 kn (1630 UTC). Analysis intensity set at 40 knots in
the northern quadrants based on ASCAT pass at 1421 UTC.
In general the environment is favourable for development with warm SSTs and
deep moisture supplied by the active monsoon. However it is apparent that 27U
is currently affected by strong vertical wind shear of about 20 knots, model
guidance indicate this may persist for the next 1 to 3 days and as a result the
development into a tropical cyclone may be slowed. During Wednesday an upper
trough passes to the south of 27U and the guidance suggests the environment may
be more favourable for development from this point onwards.
The majority of 00 UTC guidance indicate 27U could develop into a category 3
system towards Thursday or Friday. However of the latest 12 UTC guidance
available, most have the system taking a track slightly further north and
remaining in a higher sheared environment. This stagnates development during
the week and intensity and structure could fluctuate for the remainder of the
week.
The environmental steering is consistent in models, with generally westwards
motion forecast throughout the week due to a ridge to the south. Although a
weak upper trough does move over the southern Indian Ocean, it is not expected
to amplify and significantly affect the steering. As 27U leaves the Australian
region later on the weekend motion becomes more southwest as the ridge retreats
ahead of another upper trough developing in the central Indian Ocean.
Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 25/0130 UTC.
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1904 UTC 24/03/2025
Name: Tropical Low
Identifier: 27U
Data At: 1800 UTC
Latitude: 16.5S
Longitude: 110.7E
Location Accuracy: within 30nm (55 km)
Movement Towards: west southwest (251 deg)
Speed of Movement: 8 knots (14 km/h)
Maximum 10-Minute Wind: 40 knots (75 km/h)
Maximum 3-Second Wind Gust: 55 knots (100 km/h)
Central Pressure: 994 hPa
Radius of 34-knot winds NE quadrant: 20 nm (35 km)
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant: 40 nm (75 km)
Radius of 48-knot winds NE quadrant:
Radius of 48-knot winds SE quadrant:
Radius of 48-knot winds SW quadrant:
Radius of 48-knot winds NW quadrant:
Radius of 64-knot winds: nm ( km)
Radius of Maximum Winds: nm ( km)
Dvorak Intensity Code: T2.0/2.0/D1.0/24HRS STT
0.5/06HRSPressure of outermost isobar: 1004 hPa
Radius of outermost closed isobar: 170 nm (315 km)
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
(UTC) : degrees : nm (km): knots(km/h): hPa
+06: 25/0000: 16.5S 110.2E: 040 (080): 045 (085): 990
+12: 25/0600: 16.6S 109.7E: 050 (090): 040 (075): 993
+18: 25/1200: 16.7S 109.1E: 060 (110): 040 (075): 993
+24: 25/1800: 16.9S 108.4E: 065 (120): 040 (075): 994
+36: 26/0600: 17.3S 106.6E: 085 (155): 040 (075): 994
+48: 26/1800: 17.2S 104.6E: 105 (190): 045 (085): 991
+60: 27/0600: 17.1S 102.5E: 120 (220): 045 (085): 992
+72: 27/1800: 16.8S 100.4E: 120 (225): 045 (085): 991
+96: 28/1800: 17.0S 95.7E: 165 (300): 060 (110): 982
+120: 29/1800: 18.3S 91.6E: 205 (380): 070 (130): 971
REMARKS:
Tropical Low 27U lies well to the northwest of Western Australia and is
forecast to slowly develop as it tracks westwards over the Indian Ocean.
The system was located using animated satellite imagery and an ASCAT-B pass at
1421UTC. The low level centre continues to be covered by cirrus blow off.
Confidence is moderate in the location.
Dvorak analysis based on both a shear pattern yielding a 3-hourly average DT of
2.5, however there is no tight gradient, so this is unreliable. The 24 trend is
D- which gives MET of 2.0, no adj so PAT is also 2.0, FT biased to PAT. FT/CI
is 2.0. Objective aids (all 1 min mean) at 1730UTC are ADT 35 kn, AiDT 34 kn,
DPRINT 36 kn, SATCON 41 kn (1630 UTC). Analysis intensity set at 40 knots in
the northern quadrants based on ASCAT pass at 1421 UTC.
In general the environment is favourable for development with warm SSTs and
deep moisture supplied by the active monsoon. However it is apparent that 27U
is currently affected by strong vertical wind shear of about 20 knots, model
guidance indicate this may persist for the next 1 to 3 days and as a result the
development into a tropical cyclone may be slowed. During Wednesday an upper
trough passes to the south of 27U and the guidance suggests the environment may
be more favourable for development from this point onwards.
The majority of 00 UTC guidance indicate 27U could develop into a category 3
system towards Thursday or Friday. However of the latest 12 UTC guidance
available, most have the system taking a track slightly further north and
remaining in a higher sheared environment. This stagnates development during
the week and intensity and structure could fluctuate for the remainder of the
week.
The environmental steering is consistent in models, with generally westwards
motion forecast throughout the week due to a ridge to the south. Although a
weak upper trough does move over the southern Indian Ocean, it is not expected
to amplify and significantly affect the steering. As 27U leaves the Australian
region later on the weekend motion becomes more southwest as the ridge retreats
ahead of another upper trough developing in the central Indian Ocean.
Copyright Commonwealth of Australia
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The next bulletin for this system will be issued by: 25/0130 UTC.
BoM has yet to upgrade Tropical Low 27U (JTWC's Tropical Cyclone 27S) to a TC. The next name is Courtney. Meanwhile, Invest 93S (Tropical Low 28U) is getting together slowly, and the GFS expects the system to possibly form around March 27th or March 28th. If and when it forms it will likely be designated as Tropical Cyclone 28S by the JTWC. The next name on the Australian Region list after Courtney is Dianne.
Breaking: The BoM has upgraded Tropical Low 27U to Tropical Cyclone Courtney.
| IDW24000 Australian Bureau of Meteorology Tropical Cyclone Warning Centre TROPICAL CYCLONE INFORMATION BULLETIN Issued at 2:31 am WST on Wednesday 26 March 2025 Tropical Cyclone Courtney (Category 1) was located at 2:00 am AWST near 17.2S 107.3E,that is 890 km northwest of Exmouth and 770 km south southeast of Christmas Island and moving west southwest at 17 kilometres per hour. Tropical Cyclone Courtney has developed well to the northwest of the Pilbara coast and is expected to continue to move westwards, further away from the Australian mainland. It is slowly developing and likely to see some fluctuations in intensity and size over the next couple of days. Tropical Cyclone Courtney will not impact the Western Australian coast, the Cocos (Keeling) Islands or Christmas Island. The next Information Bulletin will be issued at 9:00 am AWST Wednesday 26 March. |