
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0708 UTC 26/01/2011
Name: Tropical Cyclone Bianca
Identifier: 12U
Data At: 0600 UTC
Latitude: 19.4S
Longitude: 118.2E
Location Accuracy: within 15 nm [30 km]
Movement Towards: west southwest [237 deg]
Speed of Movement: 15 knots [27 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: 60 nm [110 km]
Radius of 34-knot winds SE quadrant: 60 nm [110 km]
Radius of 34-knot winds SW quadrant: 60 nm [110 km]
Radius of 34-knot winds NW quadrant: 60 nm [110 km]
Radius of 48-knot winds NE quadrant: 30 nm [55 km]
Radius of 48-knot winds SE quadrant: 30 nm [55 km]
Radius of 48-knot winds SW quadrant: 30 nm [55 km]
Radius of 48-knot winds NW quadrant: 30 nm [55 km]
Radius of 64-knot winds:
Radius of Maximum Winds: 15 nm [30 km]
Dvorak Intensity Code: T4.0/4.0/D1.5/24HRS STT:D0.5/6HRS
Pressure of outermost isobar: 1000 hPa
Radius of outermost closed isobar: 70 nm [130 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 26/1800: 20.3S 115.6E: 045 [085]: 070 [130]: 968
+24: 27/0600: 21.2S 113.1E: 075 [140]: 080 [150]: 958
+36: 27/1800: 22.5S 110.5E: 110 [200]: 085 [155]: 953
+48: 28/0600: 24.6S 108.3E: 140 [260]: 075 [140]: 961
+60: 28/1800: 26.9S 107.0E: 190 [345]: 055 [100]: 976
+72: 29/0600: 29.4S 106.9E: 235 [435]: 040 [075]: 985
REMARKS:
1.1 banding on recent VIS imagery gives 4.0 DT. MET is 4.0 based on a D+ trend,
PAT 4.0. FT is set to 4.0 within constraints and hence CI is 4.0. SATCON at 23Z
indicated 60 knots 1-min wind, with ADT at 48 knots and CIMSS AMSU at 64 knots.
1-min winds at Bedout Island have reached a maximum of 54 knots [0405Z] as the
system centre passed close by. Bedout is on the southern side and appears to
have gone through the eyewall so will have likely experienced close to the
maximum winds at that time. Final intensity estimate is set at 55 knots 10-min
wind with relatively high confidence given the lower bounds provided by the
offshore obs and the subjective assessment of the radar and microwave imagery in
agreement with Dvorak estimates.
Radar shows inner eye wall radius of around 20-25nm with recent evidence that an
intense Cb has generated an asymmetry in the NW of the eyewall. Shear has
increased slightly [8.1m/s at 06Z] but is expected to increase only marginally
over the next 48 hours. Ocean heat content is high along the forecast track
over the next 36 hours. Hence further intensification is forecast. By late
Wednesday or Thursday it is likely to reach severe cyclone [hurricane]
intensity. Weakening is then likely from late Friday as the system moves over
cooler SSTs and experiences increasing shear.
The system is expected to be steered steadily towards the west southwest by a
strong mid-level ridge until late Friday when an amplifying trough will result
in the system being steered towards the south. On Sunday the remnants of the
system will experience very high shear as a strong surface ridge pushes in
beneath the mid level trough.
Copyright Commonwealth of Australia
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The next bulletin for this system will be issued by: 26/1300 UTC by Perth TCWC.