AXAU01 APRF 251821
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1820 UTC 25/02/2021
Name: Tropical Low
Identifier: 15U
Data At: 1800 UTC
Latitude: 13.8S
Longitude: 102.5E
Location Accuracy: within 35 nm [65 km]
Movement Towards: west southwest [256 deg]
Speed of Movement: 17 knots [31 km/h]
Maximum 10-Minute Wind: 35 knots [65 km/h]
Maximum 3-Second Wind Gust: 50 knots [95 km/h]
Central Pressure: 994 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant: 150 nm [280 km]
Radius of 34-knot winds SW quadrant: 150 nm [280 km]
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: 35 nm [65 km]
Dvorak Intensity Code: T2.5/2.5/D1.0/24HRS STT:S0.0/06HRS
Pressure of outermost isobar: 1004 hPa
Radius of outermost closed isobar: 200 nm [370 km]
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+06: 26/0000: 14.2S 100.8E: 055 [100]: 035 [065]: 995
+12: 26/0600: 14.5S 99.1E: 065 [115]: 040 [075]: 993
+18: 26/1200: 14.6S 97.7E: 070 [130]: 040 [075]: 992
+24: 26/1800: 14.7S 96.4E: 075 [145]: 045 [085]: 989
+36: 27/0600: 15.3S 94.6E: 090 [165]: 050 [095]: 985
+48: 27/1800: 15.9S 93.3E: 110 [200]: 055 [100]: 981
+60: 28/0600: 16.5S 92.4E: 130 [240]: 065 [120]: 973
+72: 28/1800: 17.1S 91.7E: 145 [265]: 070 [130]: 969
+96: 01/1800: 17.8S 90.8E: 195 [355]: 065 [120]: 972
+120: 02/1800: 18.2S 91.6E: 240 [445]: 055 [100]: 979
REMARKS:
Over the last few hours convection has increased to the west of tropical low 15U. It has is gradually strengthened although still under the constraining influence of easterly wind shear. The system was located using EIR and microwave imagery, with average confidence.

Dvorak analysis of 2.5 based upon curved band pattern 0.3-0.4 - DT of 2.5, and MET of 2.5. NOAA ADT has been consistent at 2.2 though raw T values have increased to 2.5. Scatterometer winds have 30-35 knots in southern quadrants. The system's intensity was determined to be 35 knots.

The combined synoptic influences of the monsoonal flow and the sub-tropical ridge to the south will assist in developing a larger circulation than is typical for this region. Being a large system it may also take a little longer than normal to intensify further reducing the chance of rapid intensification within the next 72 hours. Model guidance does sustain the system through 5 to 7 days in a marginally favourable environment [cooler waters].

The mid-level ridge to the south is expected to dominate the steering with a
SW
motion forecast through to Monday. From then a developing mid-latitude trough is expected to erode the ridge and slow the system.

In the longer term there is higher uncertainty - a slow drift south or southwest
over cooler waters contrasts with a potential recurvature to the southeast as the mid-latitude trough amplifies off the western Australian coast.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 26/0130 UTC.
$$
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