AXAU01 APRF 131906
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1906 UTC 13/04/2023
Name: Severe Tropical Cyclone Ilsa
Identifier: 23U
Data At: 1800 UTC
Latitude: 20.4S
Longitude: 120.1E
Location Accuracy: within 10nm (20 km)
Movement Towards: southeast (137 deg)
Speed of Movement: 14 knots (25 km/h)
Maximum 10-Minute Wind: 95 knots (175 km/h)
Maximum 3-Second Wind Gust: 135 knots (250 km/h)
Central Pressure: 951 hPa
Radius of 34-knot winds NE quadrant: 70 nm (130 km)
Radius of 34-knot winds SE quadrant: 40 nm (75 km)
Radius of 34-knot winds SW quadrant: 40 nm (75 km)
Radius of 34-knot winds NW quadrant: 70 nm (130 km)
Radius of 48-knot winds NE quadrant: 50 nm (95 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: 50 nm (95 km)
Radius of 64-knot winds: 30 nm (30 km)
Radius of Maximum Winds: 10 nm (20 km)
Dvorak Intensity Code: n/a
Pressure of outermost isobar: 1006 hPa
Radius of outermost closed isobar: 190 nm (350 km)
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
(UTC)        : degrees     :      nm  (km): knots(km/h): hPa
+06:  14/0000: 21.2S 121.4E:     025 (050):  065  (120):  968
+12:  14/0600: 21.9S 123.2E:     040 (070):  050  (095):  983
+18:  14/1200: 22.5S 125.3E:     045 (085):  045  (085):  992
+24:  14/1800: 22.8S 127.8E:     055 (100):  040  (075):  998
+36:  15/0600: 23.0S 133.3E:     065 (120):  035  (065): 1002
+48:  15/1800:             :              :            :     
+60:  16/0600:             :              :            :     
+72:  16/1800:             :              :            :     
+96:  17/1800:             :              :            :     
+120: 18/1800:             :              :            :     
REMARKS:
Severe Tropical Cyclone Ilsa, category 4, was located just inland from the West
Australian Coast. 

Ilsa crossed the coast about 120km east northeast of Port Hedland around
1600UTC with an estimated intensity of 115 knots (category 5). The cyclone is
currently moving towards the southeast and was located on radar about 60km
inland from the coast at 1800UTC. There is good confidence in the cyclone's
position based on Port Hedland weather radar and an eye is visible on satellite
imagery. 

Dvorak intensity analysis is no longer valid as the cyclone is over land.
Intensity was estimated using the overland decay model and set at 95 knots
(category 4). 

The cyclone is forecast to weaken as it accelerates towards the east southeast
while passing over the Pilbara region Friday morning and the Northern Interior
of Western Australia later on Friday. The primary steering influence is an
upper trough over southern Western Australia.  

The cyclone is forecast to lose its tropical cyclone structure early on
Saturday but strong to gale force winds may persist in the northern semicircle
as it transitions to a deep, sub-tropical system over central Australia.  

Copyright Commonwealth of Australia
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The next bulletin for this system will be issued by: 14/0130 UTC.