IDQ20018
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by BRISBANE TROPICAL CYCLONE WARNING CENTRE
at: 0716 UTC 27/03/2017
Name: Severe Tropical Cyclone Debbie
Identifier: 24U
Data At: 0700 UTC
Latitude: 19.5S
Longitude: 150.1E
Location Accuracy: within 15 nm [30 km]
Movement Towards: southwest [220 deg]
Speed of Movement: 3 knots [6 km/h]
Maximum 10-Minute Wind: 85 knots [155 km/h]
Maximum 3-Second Wind Gust: 120 knots [220 km/h]
Central Pressure: 952 hPa
Radius of 34-knot winds NE quadrant: 110 nm [205 km]
Radius of 34-knot winds SE quadrant: 140 nm [260 km]
Radius of 34-knot winds SW quadrant: 140 nm [260 km]
Radius of 34-knot winds NW quadrant: 110 nm [205 km]
Radius of 48-knot winds NE quadrant: 80 nm [150 km]
Radius of 48-knot winds SE quadrant: 80 nm [150 km]
Radius of 48-knot winds SW quadrant: 80 nm [150 km]
Radius of 48-knot winds NW quadrant: 80 nm [150 km]
Radius of 64-knot winds: 35 nm [65 km]
Radius of Maximum Winds: 20 nm [35 km]
Dvorak Intensity Code: T5.0/5.0/D1.0/24HRS
Pressure of outermost isobar: 1002 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: 27/1300: 19.7S 149.6E: 025 [050]: 090 [170]: 951
+12: 27/1900: 20.0S 148.9E: 040 [070]: 095 [175]: 950
+18: 28/0100: 20.2S 148.2E: 050 [095]: 085 [155]: 962
+24: 28/0700: 20.4S 147.5E: 065 [120]: 055 [100]: 985
+36: 28/1900: 21.0S 146.1E: 085 [155]: 035 [065]: 998
+48: 29/0700: 21.9S 145.5E: 105 [190]: 030 [055]: 1000
+60: 29/1900: 22.9S 146.2E: 125 [230]: 030 [055]: 1001
+72: 30/0700: 23.9S 148.4E: 140 [265]: 025 [050]: 1003
+96: 31/0700: 25.7S 152.9E: 185 [345]: 025 [045]: 1003
+120: 01/0700: 27.8S 156.3E: 275 [505]: 025 [045]: 1001
REMARKS:
Tropical cyclone Debbie has shown rapid development through today. Deep
convection rapidly developed around the system centre this morning, with a clear
eye developing during the day. The latest Dvorak analysis was therefore based on
an eye pattern in IR, with a LG surround and OW eye, with +0.5 for eye
adjustment DT of 5.5. MET and PT are 5.0. FT was based on DT but constrained to
5.0 due to Dvorak rules. SATCON has jumped dramatically during the day to about
90 knots. ADT from both agencies are around 5.5. Forecast system to become
category 4 in the next 6 hours.
Confidence in the centre position is rated as good based on a combination of
radar imagery from Willis Island and Bowen radars and animated visible satellite
imagery.
The mid-level ridge building to the south of the system has become the primary
steering influence. However, animated WV imagery suggests that the shortwave
trough moving north into SE Queensland may have a little more amplitude than the
models are suggesting, leading to a slight weakening of the ridge and a slightly
more southerly track which has been evident over the past 12 hours. There may
also be some influence from internal processes within the cyclone core, where it
remains somewhat disorganised. Overall, the system is most likely to remain on a
general west-southwest track for the next 24 hours up to landfall on the
Queensland coast. There is still reasonably high confidence in this track,
although there is more uncertainty on the southern side.
The system remains located in an area of weak vertical wind shear over sea
surface temperatures of 29 to 30 degrees Celsius. Conditions will remain
favourable for development right up until landfall, and this has been reflected
in an intensity forecast at a standard rate following the recent period of rapid
intensification.

Copyright Commonwealth of Australia
==