IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 2324 UTC 17/02/2018
Name: Tropical Cyclone Kelvin
Identifier: 17U
Data At: 2230 UTC
Latitude: 19.2S
Longitude: 121.4E
Location Accuracy: within 15 nm [30 km]
Movement Towards: east [090 deg]
Speed of Movement: 5 knots [9 km/h]
Maximum 10-Minute Wind: 55 knots [100 km/h]
Maximum 3-Second Wind Gust: 80 knots [150 km/h]
Central Pressure: 980 hPa
Radius of 34-knot winds NE quadrant: 50 nm [95 km]
Radius of 34-knot winds SE quadrant: 35 nm [65 km]
Radius of 34-knot winds SW quadrant: 35 nm [65 km]
Radius of 34-knot winds NW quadrant: 50 nm [95 km]
Radius of 48-knot winds NE quadrant: 20 nm [35 km]
Radius of 48-knot winds SE quadrant: 20 nm [35 km]
Radius of 48-knot winds SW quadrant: 20 nm [35 km]
Radius of 48-knot winds NW quadrant: 20 nm [35 km]
Radius of 64-knot winds:
Radius of Maximum Winds: 10 nm [20 km]
Dvorak Intensity Code: T4.0/4.0/D1.5/24HRS STT:D0.5/06HRS
Pressure of outermost isobar: 998 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: 18/0430: 19.4S 121.7E: 030 [055]: 040 [075]: 986
+12: 18/1030: 19.8S 122.1E: 050 [095]: 035 [065]: 987
+18: 18/1630: 20.4S 122.4E: 060 [110]: 035 [065]: 990
+24: 18/2230: 21.1S 122.5E: 075 [140]: 035 [065]: 993
+36: 19/1030: 22.7S 122.8E: 100 [185]: 030 [055]: 992
+48: 19/2230: 24.2S 122.9E: 120 [220]: 030 [055]: 991
+60: 20/1030: 25.8S 123.1E: 140 [255]: 030 [055]: 991
+72: 20/2230: 27.5S 123.8E: 155 [290]: 030 [055]: 992
+96: 21/2230: : : :
+120: 22/2230: : : :
REMARKS:
Tropical Cyclone Kelvin crossed the west Kimberley coast [southwest of Broome]
between 6 and 7am AWST [18/22-23UTC]. The cyclone developed rapidly in the six
hours prior to landfall to be an estimated 55kn [category 2] system. Broome
radar, IR imagery and particularly microwave [SSMIS at 1932UTC and 2127UTC]
indicated this development.
Dvorak analysis: FT/CI estimated at 4.0. The previous estimate at 18UTC has been
upgraded to 3.5 which just avoids breaking intensification constraints. The most
recent IR images near 23UTC show indications of an eye, suggesting a DT=4.5. A
ragged eye on the initial Vis images of the day suggests a 3.5 [0.5 degree less
adjustment], however being a small system the intensity is likely to be higher
than the Vis eye pattern suggests. The latest SATCON at 70kn [corrected to 10min
average] is higher.
Kelvin is a small system having gales estimated to less than 100km from the
centre.
The cyclone should now move over land and gradually weaken but at a slower rate
than normal given the favourable atmospheric environment [low shear and upper
level divergence], the flat terrain and slow movement.
Gales may be sustained on the eastern flank for longer supported by a ridge to
the southeast.
Copyright Commonwealth of Australia
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The next bulletin for this system will be issued by: 18/0700 UTC by Perth TCWC.
