SIO: ZELIA - Post-Tropical

[Subtrop]

96S INVEST 250207 1200 13.9S 126.3E SHEM 15 1002

[cycloneye]

Developing tropical low near the north Kimberley coast potentially becoming a tropical cyclone on Monday.

Areas Affected:
Warning Zone
None.

Watch Zone
Cockatoo Island to Bidyadanga, including Broome.

Cancelled Zone
None.

Details of Tropical Low 18U at 2:00 am AWST:
Intensity: Tropical Low, sustained winds near the centre of 35 kilometres per hour with wind gusts to 85 kilometres per hour.

Location: within 55 kilometres of 14.5 degrees South 123.9 degrees East, estimated to be 425 kilometres north northeast of Broome and 130 kilometres north northwest of Kuri Bay.

[Hurricane2022]

This is going to be a big one. Not really sure if it will affect AUS coast yet but bears watching.

[Hurricane2022]

Otis II? Frontal low Milton?
 https://x.com/KacperWx/status/1888562003289022845

[cycloneye]

Details of Tropical Low 18U at 8:00 pm AWST:
Intensity: Tropical Low, sustained winds near the centre of 35 kilometres per hour with wind gusts to 85 kilometres per hour.

Location: within 75 kilometres of 14.8 degrees South 123.4 degrees East, estimated to be 370 kilometres north northeast of Broome and 140 kilometres west northwest of Kuri Bay.

Movement: slow moving.

A tropical low (18U) is slowly forming near the north Kimberley coast. The low is forecast to move southwest off the Kimberley coast and develop, potentially reaching cyclone intensity on Tuesday. The system is then forecast to move further to the southwest towards the Pilbara coast while strengthening further.

Hazards:
Gales with DAMAGING WIND GUSTS to 100 kilometres per hour may develop near the Kimberley coast between Cape Leveque and Beagle Bay from Tuesday morning, if the system moves further south than forecast. These DAMAGING WIND GUSTS may extend further towards Broome and Bidyadanga during Tuesday and to De Grey on Tuesday night.

Locally heavy falls are possible near the Kimberley coast between Cape Leveque and Broome from Monday afternoon, potentially becoming more widespread and shifting to the coast between Beagle Bay and De Grey during Tuesday.

Abnormally high tides are possible tonight and Monday between Kuri Bay and Cape Leveque, extending further south to Broome and Bidyadanga on Tuesday. The sea level should not exceed the highest tide of the year around the Kimberley coast.

[Hurricane2022]

Australian Boreau of Met. is predicting a C4 STC (AUS Scale) making landfall between Port Hedland and Karratha

[cycloneye]

Details of Tropical Low 18U at 2:00 am AWST:
Intensity: Tropical Low, sustained winds near the centre of 35 kilometres per hour with wind gusts to 85 kilometres per hour.

Location: within 55 kilometres of 14.7 degrees South 122.2 degrees East, estimated to be 360 kilometres north of Broome and 265 kilometres west northwest of Kuri Bay.

Movement: west at 13 kilometres per hour.

A tropical low (18U) is slowly forming northwest of the Kimberley coast. The low is forecast to move southwest and gradually develop, potentially reaching cyclone intensity on Tuesday. The system is then forecast to move further to the southwest towards the Pilbara coast while strengthening further.

Hazards:
Gales with DAMAGING WIND GUSTS to 100 kilometres per hour may develop near the Kimberley coast between Cape Leveque and Beagle Bay from Tuesday, if the system moves further south than forecast. These DAMAGING WIND GUSTS may extend further towards Broome and Bidyadanga during Tuesday afternoon and to De Grey on Tuesday night.

Locally heavy falls are possible near the Kimberley coast between Cape Leveque and Broome from Monday afternoon, potentially becoming more widespread and shifting to the coast between Beagle Bay and De Grey during Tuesday.

Abnormally high tides are possible Monday between Kuri Bay and Cape Leveque, extending further south to Broome and Bidyadanga on Tuesday. The sea level should not exceed the highest tide of the year around the Kimberley coast.

[cycloneye]

Details of Tropical Low 18U at 8:00 am AWST:
Intensity: Tropical Low, sustained winds near the centre of 35 kilometres per hour with wind gusts to 85 kilometres per hour.

Location: within 75 kilometres of 15.1 degrees South 121.8 degrees East, estimated to be 320 kilometres north of Broome and 185 kilometres northwest of Cape Leveque.

Movement: southwest at 11 kilometres per hour.

A weak tropical low (18U) is slowly forming northwest of the Kimberley coast. The low is forecast to move southwest and slowly develop, potentially reaching cyclone intensity on Wednesday. The system is then forecast to move further towards the Pilbara coast but be slow moving on Thursday and Friday while strengthening further. There is high variability in location and intensity of the system by landfall.

[cycloneye]

Details of Tropical Low 18U at 8:00 pm AWST:
Intensity: Tropical Low, sustained winds near the centre of 35 kilometres per hour with wind gusts to 85 kilometres per hour.

Location: within 110 kilometres of 15.0 degrees South 121.1 degrees East, estimated to be 350 kilometres north northwest of Broome and 250 kilometres northwest of Cape Leveque.

Movement: west at 7 kilometres per hour.

A weak tropical low (18U) off the northwest of the Kimberley is expected to move south and slowly develop over the next few days. There is high uncertainty regarding the forecast intensity and track from mid-week, but it may develop further and approach the coast as a significant system later in the week.

Hazards:
Gales with DAMAGING WIND GUSTS to 100 kilometres per hour may develop along the coast between Cape Leveque and Port Hedland during Wednesday or Thursday.

Locally heavy falls may develop along the coast between Cape Leveque and Port Hedland during Wednesday or Thursday. The slow movement of the system as it approaches the coast may result in very high falls near the track. Refer to Flood Watch for further information.

Abnormally high tides are possible between Cape Leveque and Port Hedland on Wednesday but sea levels should not exceed the highest tide of the year. Higher tides may occur as the system nears the coast.

Recommended Action:

[cycloneye]

What the heck.

[Hurricane2022]

What the heck.

https://i.imgur.com/OKSCgZj.png

 https://x.com/hurricane_chase/status/1888966830779236830



Very Hot take here. I think that future STC Zelia will peak at around 75 - 180 mph before landfall.

[cycloneye]

Tropical low (18U) off the northwest Kimberley developing slowing and moving southwest.

Areas Affected:
Warning Zone
None.

Watch Zone
Cape Leveque to Port Hedland, including Broome.

Cancelled Zone
None.

Details of Tropical Low 18U at 2:00 am AWST:
Intensity: Tropical Low, sustained winds near the centre of 45 kilometres per hour with wind gusts to 85 kilometres per hour.

Location: within 75 kilometres of 15.7 degrees South 120.9 degrees East, estimated to be 290 kilometres north northwest of Broome and 230 kilometres west northwest of Cape Leveque.

Movement: southwest at 9 kilometres per hour.

A tropical low (18U) to the northwest of the Kimberley coast is expected to move south and slowly develop over the next few days. It is expected to approach the coast as a significant system later in the week. There is high uncertainty regarding its forecast intensity and track from mid-week.

[cycloneye]

Details of Tropical Low 18U at 2:00 pm AWST:
Intensity: Tropical Low, sustained winds near the centre of 75 kilometres per hour with wind gusts to 100 kilometres per hour.

Location: within 55 kilometres of 16.7 degrees South 119.6 degrees East, estimated to be 315 kilometres west northwest of Broome and 415 kilometres north northeast of Port Hedland.

Movement: south southwest at 13 kilometres per hour.

A tropical low (18U), currently located to the northwest of Broome, is expected to move south and develop into a tropical cyclone during Wednesday. The system is forecast to continue moving south and intensify, possibly reaching Category 3 while still north of the Pilbara coast. 18U may be slow moving during Thursday and Friday before crossing the east Pilbara or west Kimberley coast as a severe tropical cyclone later this week.

[cycloneye]

JTWC begin warnings.

[cycloneye]

Organizing at a good rate.

[cycloneye]

Looks like BoM will name it at the next warning.

TROPICAL CYCLONE ADVICE NUMBER 16
Issued at 8:47 pm WST on Tuesday 11 February 2025

Headline:
Tropical low 18U is forecast to develop into a tropical cyclone early Wednesday before impacting the east Pilbara or west Kimberley coast later this week.

Areas Affected:
Warning Zone
Broome to Port Hedland, including Port Hedland and not including Broome.

Watch Zone
Port Hedland to Dampier and inland to Marble Bar including Marble Bar

Cancelled Zone
None.

Details of Tropical Low 18U at 8:00 pm AWST:
Intensity: Tropical Low, sustained winds near the centre of 75 kilometres per hour with wind gusts to 100 kilometres per hour.

Location: within 75 kilometres of 17.4 degrees South 119.6 degrees East, estimated to be 285 kilometres west northwest of Broome and 340 kilometres north northeast of Port Hedland.

Movement: south at 13 kilometres per hour.

Tropical low 18U is expected to develop into a tropical cyclone during Wednesday as it continues moving south. 18U is likely to become slow moving during Thursday while offshore of the east Pilbara coast where it is expected to strengthen further, possibly reaching Category 3. 18U is then expected to cross the east Pilbara or west Kimberley coast as a severe tropical cyclone later this week.

[cycloneye]

REMARKS:
Tropical cyclone Zelia has been located using infra-red and microwave imagery
(GMI at 1606UTC). The centre lies northeast of the deep convection reflecting
ongoing northeasterly wind shear. Persistent strong gales have been observed
at Rowley Shoals (west of the centre).
Dvorak analysis: DT is 2.5 based on a shear pattern. MET is 2.5 based on a D 24
hour trend with no adjustment made. FT and CI are both 2.5. Intensity is set at
45 knots from Rowley Shoals observations. Objective guidance: CIMSS SATCON
47kn, ADT 43 kn, AIDT 36 kn, DPRINT 39 kn, DMINT 38kn (all 1-minute mean).
Other than the ongoing northeasterly wind shear (CIMSS 22kn), the environment
is favourable for development: the sea surface temperatures are very warm
(above 31C) with very good upper outflow and divergence. The upper trough will
maintain the upper divergence and the shear is forecast to decrease supporting
the intensification of Zelia. The available moisture may be somewhat limited at
times according to some model guidance. The intensity forecast increases to
85kn (category 3) on Friday prior to landfall, although some guidance such as
HFSA would indicate a much higher intensity.
Tropical cyclone Zelia is currently being steered slowly to the south by a weak
mid-level ridge to the east. The ridge is forecast to weaken further as the
mid-level trough passes to the south resulting in Zelia moving very slowly in
the next 36-48h. During Friday most guidance indicates that the strong and deep
circulation will take a more defined southeast track to make landfall and move
inland, although the exact timing remains a challenge.

[WaveBreaking]

This is either a surprise clearing eye or the most ridiculous CCC pattern I’ve ever seen

[cycloneye]

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 0058 UTC 12/02/2025
Name: Tropical Cyclone Zelia
Identifier: 18U
Data At: 0000 UTC
Latitude: 18.1S
Longitude: 119.6E
Location Accuracy: within 30nm (55 km)
Movement Towards: south (180 deg)
Speed of Movement: 4 knots (6 km/h)
Maximum 10-Minute Wind: 45 knots (85 km/h)
Maximum 3-Second Wind Gust: 65 knots (120 km/h)
Central Pressure: 985 hPa
Radius of 34-knot winds NE quadrant: 50 nm (95 km)
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant: 70 nm (130 km)
Radius of 34-knot winds NW quadrant: 60 nm (110 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: 25 nm (45 km)
Dvorak Intensity Code: T3.0/3.0/D1.5 24HRS STT: D0.5/06 HRS
Pressure of outermost isobar: 1000 hPa
Radius of outermost closed isobar: 150 nm (280 km)
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
(UTC) : degrees : nm (km): knots(km/h): hPa
+06: 12/0600: 18.6S 119.6E: 040 (080): 050 (095): 985
+12: 12/1200: 18.7S 119.5E: 055 (100): 055 (100): 984
+18: 12/1800: 18.8S 119.4E: 070 (125): 060 (110): 980
+24: 13/0000: 19.0S 119.2E: 080 (145): 065 (120): 978
+36: 13/1200: 19.2S 118.9E: 095 (180): 070 (130): 974
+48: 14/0000: 19.6S 119.0E: 130 (240): 085 (155): 974
+60: 14/1200: 20.7S 119.4E: 150 (275): 065 (120): 981
+72: 15/0000: 21.9S 119.7E: 165 (310): 035 (065): 992
+96: 16/0000: 24.8S 119.5E: 220 (410): 030 (055): 999
+120: 17/0000: 26.2S 120.6E: 280 (520): 025 (045): 1002
REMARKS:
Tropical Cyclone Zelia is difficult to locate with the centre located near or
just under deep convection. Convection remains to the southwest of the centre,
reflecting the ongoing impact of northeasterly wind shear. The centre is
estimated using the few low cloud lines that we can see on visible imagery.

Persistent gales have been observed at Rowley Shoals (west of the centre).

Dvorak analysis: DT is 3.0 based on a shear pattern. MET is 2.5 based on a D 24
hour trend with no adjustment made. FT and CI are both 3.0. Intensity is set at
45 knots from Rowley Shoals observations. Objective guidance at 2340UTC: CIMSS
SATCON 49kn(2030UTC), ADT 49 kn, AIDT 40 kn, DPRINT 56 kn, (all 1-minute mean).

Other than the ongoing northeasterly wind shear, or about 20 knots, the
environment is favourable for development: the sea surface temperatures are
extremely warm (above 31C) with very good upper outflow and divergence. The
upper trough will maintain the upper divergence and the shear is forecast to
decrease, hence intensification of Zelia until landfall is likely. There is
some drier air in the mid-levels to the west of Zelia, though this is generally
forecast to stay to the west and is not expected to limit intensification
before landfall. The intensity forecast increases to 85kn (category 3) on
Friday prior to landfall later that day, although some guidance such as HFSA
would indicate a much higher intensity is possible.

Tropical Cyclone Zelia is currently being steered slowly to the south by a
mid-level ridge to the east. The ridge is forecast to weaken further as the
mid-level trough passes to the south Wednesday resulting in Zelia moving very
slowly in the next 36-48h. During Friday most guidance indicates that the
strong and deep circulation will take a more defined southeast track to make
landfall and move inland, although the exact timing remains a challenge.

[cycloneye]

Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 0647 UTC 12/02/2025
Name: Tropical Cyclone Zelia
Identifier: 18U
Data At: 0600 UTC
Latitude: 18.9S
Longitude: 118.7E
Location Accuracy: within 15nm (30 km)
Movement Towards: south southwest (213 deg)
Speed of Movement: 8 knots (14 km/h)
Maximum 10-Minute Wind: 55 knots (100 km/h)
Maximum 3-Second Wind Gust: 75 knots (140 km/h)
Central Pressure: 980 hPa
Radius of 34-knot winds NE quadrant: 65 nm (120 km)
Radius of 34-knot winds SE quadrant: 75 nm (140 km)
Radius of 34-knot winds SW quadrant: 85 nm (155 km)
Radius of 34-knot winds NW quadrant: 80 nm (150 km)
Radius of 48-knot winds NE quadrant: 40 nm (75 km)
Radius of 48-knot winds SE quadrant: 40 nm (75 km)
Radius of 48-knot winds SW quadrant: 40 nm (75 km)
Radius of 48-knot winds NW quadrant: 40 nm (75 km)
Radius of 64-knot winds: nm ( km)
Radius of Maximum Winds: 20 nm (40 km)
Dvorak Intensity Code: T3.5/3.5/D1.5 24HRS STT: D0.5/06 HRS
Pressure of outermost isobar: 1002 hPa
Radius of outermost closed isobar: 180 nm (335 km)
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
(UTC) : degrees : nm (km): knots(km/h): hPa
+06: 12/1200: 19.0S 118.7E: 030 (050): 055 (100): 977
+12: 12/1800: 19.0S 118.6E: 035 (065): 060 (110): 973
+18: 13/0000: 19.1S 118.5E: 055 (105): 065 (120): 969
+24: 13/0600: 19.2S 118.5E: 075 (140): 070 (130): 965
+36: 13/1800: 19.5S 118.5E: 100 (185): 080 (150): 957
+48: 14/0600: 20.1S 118.7E: 135 (245): 085 (155): 956
+60: 14/1800: 21.0S 119.0E: 150 (280): 050 (095): 982
+72: 15/0600: 22.6S 119.3E: 170 (315): 030 (055): 992
+96: 16/0600: 25.5S 119.7E: 230 (425): 030 (055): 992
+120: 17/0600: : : :
REMARKS:
An ASCAT pass at 0030 UTC and the centre now able to be tracked on the Port
Hedland Radar mean we now have much more confidence in the centre location.
This has also seen a jump to the southwest compared to our earlier analysis.

Convection has improved, and while there is still some influence of wind shear,
we are now seeing improved curved banding, AMSU microwave at 0151 UTC nicely
shows this.
Zelia has moved to the south of Rowley Shoals (north of the centre), and
previous gales have eased.
Dvorak analysis: DT is 3.0 based on a curved band pattern with a wrap of 0.7.
MET is 3.5 based on a D+ 24 hour trend with no adjustment made. FT and CI are
both 3.5 based on MET. Intensity is set at 55 knots based on earlier ASCAT at
0030 with a 50 knot system and the fact that we have developed further since
then. Objective guidance at 0500UTC: CIMSS SATCON 61kn(0210UTC), ADT 57 kn,
AIDT 47 kn, DPRINT 62 kn, (all 1-minute mean).

Northeasterly wind shear is easing and is now about 15 knots and the remaining
environmental factors are favourable for development: the sea surface
temperatures are extremely warm (above 31C) with very good upper outflow and
divergence. An upper trough will maintain the upper divergence and the shear is
forecast to further decrease, hence intensification of Zelia until landfall is
likely. There is some drier air in the mid-levels to the west of Zelia, though
this is generally forecast to stay to the west and is not expected to limit
intensification before landfall. The intensity forecast increases to 85kn
(category 3) on Friday prior to landfall later that day, although some guidance
would indicate a much higher intensity is possible and there is much variation
in the timing of coastal crossing.

Tropical Cyclone Zelia is currently being steered slowly to the south, in a
weak steering pattern. Zelia sits in a col with a mid-level high either side
and an upper trough to the south. Over the last 3 hours the speed of motion has
slowed, and we are forecasting continued slow motion over the next 36-48h.
Motion is currently most likely to the south, however, there is a lot of
variation in ensemble guidance over the direction that Zelia may move. During
Friday most guidance indicates that the strong and deep circulation will take a
more defined southeast track to make landfall and move inland, although the
exact timing remains a challenge.