IDW27700
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 2249 UTC 30/04/2017
Name: Ex-Tropical Cyclone Greg
Identifier: 30U
Data At: 2100 UTC
Latitude: 10.5S
Longitude: 98.8E
Location Accuracy: within 20 nm [35 km]
Movement Towards: west [270 deg]
Speed of Movement: 9 knots [16 km/h]
Maximum 10-Minute Wind: 30 knots [55 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 1002 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant:
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:
Radius of Maximum Winds:
Dvorak Intensity Code: T2.0/2.5/S0.0/24HRS STT:W0.5/06HRS
Pressure of outermost isobar: 1010 hPa
Radius of outermost closed isobar: 80 nm [150 km]
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+06: 01/0300: 10.5S 97.9E: 040 [080]: 030 [055]: 1004
+12: 01/0900: 10.4S 97.1E: 055 [100]: 030 [055]: 1005
+18: 01/1500: 10.4S 96.1E: 065 [125]: 030 [055]: 1006
+24: 01/2100: 10.4S 95.0E: 080 [145]: 030 [055]: 1006
+36: 02/0900: 10.4S 93.2E: 100 [185]: 025 [045]: 1008
+48: 02/2100: 10.8S 91.3E: 120 [220]: 025 [045]: 1008
+60: 03/0900: 10.9S 89.4E: 140 [255]: 025 [045]: 1008
+72: 03/2100: 11.0S 87.6E: 155 [290]: 025 [045]: 1008
+96: 04/2100: 12.0S 83.7E: 200 [370]: 025 [045]: 1008
+120: 05/2100: : : :
REMARKS:
TC Greg has been located by microwave and IR imagery with the IR showing the low
level centre well west of the deep convection.
With the LLC about 1.25 degrees from the deep convection, Dvorak shear pattern
gives a DT of 1.5. A weakening trend gives MET of 2.0, PAT adjusted to 1.5. FT
is 2.0 due to constraints and CI is held 0.5 higher at 2.5. This gives a max 10
minute wind of 30 knots and the system is below tropical cyclone intensity.
The environment is forecast to further deteriorate during Monday as shear
increases and with the possible entrainment of dry air. Thus, further weakening
is likely.
With steering being dominated by a high pressure ridge to the south, Greg is
forecast to continue to move to the west. Model guidance is consistent in this
forecast track as well as a weakening trend in the intensity.
Copyright Commonwealth of Australia
==
There will be no further bulletins for this system unless it reintensifies.
Australian Government Bureau of Meteorology
Western Australia
Tropical Cyclone Warning Centre
Media: The Standard Emergency Warning Signal should NOT be used with this warning.
PRIORITY
TROPICAL CYCLONE ADVICE NUMBER 2
Issued at 2:56 pm WST on Sunday 30 April 2017
Headline:
Tropical Cyclone Greg to move west and pass just north of the Cocos Islands late Monday night or early Tuesday.
Areas Affected:
Warning Zone
None.
Watch Zone
the Cocos (Keeling) Islands.
Cancelled Zone
None.
Details of Tropical Cyclone Greg at 12:30 pm CCT:
Intensity: Category 1, sustained winds near the centre of 65 kilometres per hour with wind gusts to 95 kilometres per hour.
Location: within 35 kilometres of 10.4 degrees South 101.3 degrees East, estimated to be 525 kilometres east northeast of Cocos Island and 480 kilometres west of Christmas Island.
Movement: southwest at 12 kilometres per hour.
Tropical Cyclone Greg developed quickly overnight and during this morning. It may reach category 2 intensity tonight as it continues moving generally west but then start weakening later Monday. It is forecast to pass to the north of the Cocos Islands late Monday or early Tuesday.
Hazards:
GALES with gusts to 100 km/hr may develop over the Cocos Islands as early as Monday afternoon if the tropical low takes a more southerly track.
Recommended Action:
The Australian Federal Police advise that there are no community alerts at present.
Communities on Home and West Island should listen for the next advice.
Next Advice:
The next advice will be issued by 7:30 pm CCT Sunday 30 April.
Cyclone advices and DFES Alerts are available by dialling 13 DFES (13 3337)
IDW27700
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0309 UTC 30/04/2017
Name: Tropical Low
Identifier: 30U
Data At: 0000 UTC
Latitude: 10.0S
Longitude: 101.8E
Location Accuracy: within 30 nm [55 km]
Movement Towards: south southwest [206 deg]
Speed of Movement: 2 knots [4 km/h]
Maximum 10-Minute Wind: 30 knots [55 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 1006 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant:
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:
Radius of Maximum Winds:
Dvorak Intensity Code: T2.5/2.5/D1.5/24HRS STT : D0.5/06HRS
Pressure of outermost isobar: 1010 hPa
Radius of outermost closed isobar: 90 nm [165 km]
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+06: 30/0600: 10.2S 101.6E: 040 [080]: 035 [065]: 1002
+12: 30/1200: 10.3S 101.0E: 055 [100]: 040 [075]: 1002
+18: 30/1800: 10.4S 100.3E: 065 [125]: 045 [085]: 1000
+24: 01/0000: 10.4S 99.5E: 080 [145]: 045 [085]: 997
+36: 01/1200: 10.1S 97.6E: 100 [185]: 040 [075]: 1000
+48: 02/0000: 10.2S 95.5E: 120 [220]: 030 [055]: 1006
+60: 02/1200: 10.1S 93.7E: 140 [255]: 030 [055]: 1005
+72: 03/0000: 10.4S 92.0E: 155 [290]: 025 [045]: 1008
+96: 04/0000: 10.7S 88.4E: 200 [370]: 025 [045]: 1008
+120: 05/0000: 12.4S 85.6E: 290 [535]: 025 [045]: 1008
REMARKS:
The tropical low was located using microwave imagery and animated visible and
infrared imagery with some confidence.
Microwave imagery overnight showed a small tight circulation in the low levels
and upper levels [1806UTC and 2119UTC passes]. Dvorak is problematic due to the
small size and rapid development of the system. Initial classification could be
re-analysed to 00Z Saturday. Based on this and a D+ development, FT and CI are
2.5 at 00Z. Soon to arrive ASCAT should provide more information as to the
surface circulation.
Current intensity is set to 30 knots based on a CI of 2.5.
Shear is currentkly 5 to 10 knots [low] and forecast to remain that way until
mid Monday when it starts to increase. Thus, a strengthening trend is forecast
for the short term. Due to the small size, the system may reach category 2
tonight. A weakening trend is forecast for late Monday. The track has the system
moving over cooler SST's which should further weaken the system.
Track is based on a concensus of global models [ECMWF, UK, US-GFS and ACCESS-G].
Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 30/0730 UTC by Perth TCWC.
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