AXAU01 APRF 020637
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 0636 UTC 02/04/2023
Name: Ex-Tropical Cyclone Herman
Identifier: 21U
Data At: 0600 UTC
Latitude: 19.8S
Longitude: 105.6E
Location Accuracy: within 15nm (30 km)
Movement Towards: west southwest (255 deg)
Speed of Movement: 6 knots (11 km/h)
Maximum 10-Minute Wind: 35 knots (65 km/h)
Maximum 3-Second Wind Gust: 50 knots (95 km/h)
Central Pressure: 996 hPa
Radius of 34-knot winds NE quadrant: 
Radius of 34-knot winds SE quadrant: 
Radius of 34-knot winds SW quadrant: 40 nm (75 km)
Radius of 34-knot winds NW quadrant: 30 nm (55 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:  nm ( km)
Radius of Maximum Winds: 15 nm (30 km)
Dvorak Intensity Code: T2.5/3.0/W2.0/24HRS STT:W0.5/06HRS
Pressure of outermost isobar: 1006 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:  02/1200: 19.8S 105.2E:     035 (065):  030  (055):  996
+12:  02/1800: 19.8S 104.9E:     050 (090):  030  (055): 1000
+18:  03/0000: 19.8S 104.7E:     065 (120):  030  (055): 1000
+24:  03/0600: 19.8S 104.4E:     080 (150):  025  (045): 1003
+36:  03/1800: 19.3S 103.6E:     115 (215):  025  (045): 1005
+48:  04/0600: 18.7S 102.3E:     135 (255):  025  (045): 1005
+60:  04/1800: 18.0S 100.8E:     160 (290):  025  (045): 1004
+72:  05/0600: 17.6S  99.3E:     190 (355):  025  (045): 1003
+96:  06/0600:             :              :            :     
+120: 07/0600:             :              :            :     
REMARKS:
Ex-Tropical Cyclone Herman has weakened rapidly as it moves to the west
southwest. 

Deep convection has dissipated near the centre as a result of dry air being
ingested into the circulation, revealing a distinct low level centre on visible
imagery.   

Intensity 35kn based on recent ASCAT-B and C that shows a small region of gales
west of the centre, well less than 50% around the centre. This is slightly
lower than standard metrics -these are not capturing the rapid weakening from
such a small system. Dvorak analysis: unable to determine DT; MET 2.5 (adjusted
down) but FT constrained to 2.5 and CI held at 3.0. Objective guidance (1minute
mean): ADT raw Tno 1.5 but CI constrained higher to 3.3 (51kn); AiDT 47kn;
SATCON 44kn. 

Gales may continue for up to 6 hours in the southwest quadrant, somewhat
assisted by the storm motion and synoptic flow. 

While there may be renewed bursts of deep convection near the centre, there is
little chance of redevelopment and this is reflected in the range of model
guidance.  

The motion is now more definitively to the west southwest and a gradual shift
to the west northwest should occur.  

Copyright Commonwealth of Australia
==
There will be no further bulletins for this system.