AXAU01 APRF 161909
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1909 UTC 16/01/2021
Name: Tropical Cyclone Joshua
Identifier: 07U
Data At: 1800 UTC
Latitude: 17.3S
Longitude: 91.4E
Location Accuracy: within 25 nm [45 km]
Movement Towards: west southwest [242 deg]
Speed of Movement: 6 knots [12 km/h]
Maximum 10-Minute Wind: 40 knots [75 km/h]
Maximum 3-Second Wind Gust: 55 knots [100 km/h]
Central Pressure: 992 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant: 70 nm [130 km]
Radius of 34-knot winds SW quadrant: 70 nm [130 km]
Radius of 34-knot winds NW quadrant: 40 nm [75 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:
Radius of Maximum Winds: 25 nm [45 km]
Dvorak Intensity Code: T2.5/3.0/D0.5/24HRS STT:W0.5/06HRS
Pressure of outermost isobar: 1002 hPa
Radius of outermost closed isobar: 100 nm [185 km]
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+06: 17/0000: 17.6S 90.7E: 040 [080]: 040 [075]: 992
+12: 17/0600: 18.0S 90.0E: 055 [100]: 040 [075]: 992
+18: 17/1200: 18.3S 89.4E: 060 [115]: 040 [075]: 991
+24: 17/1800: 18.6S 88.7E: 070 [130]: 040 [075]: 991
+36: 18/0600: 19.1S 87.4E: 080 [150]: 035 [065]: 991
+48: 18/1800: 19.2S 85.8E: 100 [185]: 035 [065]: 994
+60: 19/0600: 19.4S 84.0E: 115 [210]: 030 [055]: 998
+72: 19/1800: 19.8S 81.7E: 125 [235]: 030 [055]: 998
+96: 20/1800: : : :
+120: 21/1800: : : :
REMARKS:
Following a day-time period of vigorous convection over the centre, since 11UTC convection has dramatically weakened exposing the centre on IR imagery. The
ost
recent IR imagery is showing some renewed convection in southern quadrants with curvature evident. Whilst the cloud structure is quite symmetrical under low wind shear, without renewed convection the circulation may struggle as a TC and intensity forecasts have been eased back somewhat.

None of the ascending scat passes [ASCAT/SCATSAT/HY2B] provided coverage over the circulation, so intensity of 40kn based on Dvorak with some influence from ADT/SATCON [-45kn]. Dvorak FT estimated at 2.5 [3h curved band 0.5 wrap] but CI held at 3.0.

The environment remains moderately favourable for the circulation, shear is low easterly, with upper level outflow assisted by an upper trough to the south, with deep moisture connected to the tropics. However SSTs are only marginal at around 27C and there is limited low-level inflow from the north - factors that may ultimately account for the lack of development.

Latest model guidance have eased back on intensification, and restrict the area of gales largely to southern quadrants before weakening after about +48h.

A general west southwest track is expected to persist associated with a weak mid-level ridge to the south.

Copyright Commonwealth of Australia
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The next bulletin for this system will be issued by: 17/0130 UTC.
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