AXAU01 APRF 281259
IDW27600

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1259 UTC 28/02/2021

Name: Severe Tropical Cyclone Marian
Identifier: 15U
Data At: 1200 UTC
Latitude: 17.5S
Longitude: 91.3E
Location Accuracy: within 15 nm [30 km]
Movement Towards: southwest [224 deg]
Speed of Movement: 6 knots [10 km/h]
Maximum 10-Minute Wind: 80 knots [150 km/h]
Maximum 3-Second Wind Gust: 110 knots [205 km/h]
Central Pressure: 962 hPa
Radius of 34-knot winds NE quadrant: 100 nm [185 km]
Radius of 34-knot winds SE quadrant: 150 nm [280 km]
Radius of 34-knot winds SW quadrant: 130 nm [240 km]
Radius of 34-knot winds NW quadrant: 120 nm [220 km]
Radius of 48-knot winds NE quadrant: 60 nm [110 km]
Radius of 48-knot winds SE quadrant: 60 nm [110 km]
Radius of 48-knot winds SW quadrant: 90 nm [165 km]
Radius of 48-knot winds NW quadrant: 100 nm [185 km]
Radius of 64-knot winds:
Radius of Maximum Winds: 15 nm [30 km]
Dvorak Intensity Code: T5.0/5.0/D1.0/24HRS STT:D0.5/6HRS
Pressure of outermost isobar: 1002 hPa
Radius of outermost closed isobar: 220 nm [405 km]
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+06: 28/1800: 17.9S 90.8E: 035 [065]: 085 [155]: 957
+12: 01/0000: 18.1S 90.4E: 040 [080]: 085 [155]: 953
+18: 01/0600: 18.3S 90.1E: 045 [085]: 085 [155]: 952
+24: 01/1200: 18.5S 89.9E: 045 [080]: 085 [155]: 952
+36: 02/0000: 18.7S 89.8E: 045 [085]: 080 [150]: 955
+48: 02/1200: 18.8S 90.2E: 060 [115]: 080 [150]: 957
+60: 03/0000: 19.0S 91.1E: 085 [155]: 075 [140]: 962
+72: 03/1200: 19.6S 92.3E: 105 [190]: 070 [130]: 967
+96: 04/1200: 21.3S 94.8E: 145 [270]: 050 [095]: 982
+120: 05/1200: 23.5S 96.9E: 205 [380]: 045 [085]: 985
REMARKS:
Microwave satellite imagery during the afternoon and evening has given good confidence in the location and structure of Severe Tropical Cyclone Marian. The microwave imagery showed a complete eye wall structure at 0700 UTC however subsequent imagery has shown some erosion of the eastern side of the eye wall.

A consistent eye has appeared in IR imagery and despite some warming of the surrounding cold cloud Marian has intensified.

DVK eye pattern with LG surrounding temperature with an OW eye in B surround yields DT of 5.0. The eye has been symmetric in appearance and no adjustment downward has been made. A trend of D was applied to get a MET of 5.0, PAT is also at 5.0. SATCON estimates continue to show elevated values with 1-min winds now at 110 knots. ADT 1-min estimates are also over 100 knots. The 10-minute intensity has been increased to 80 knots, held slightly below objective guidance due to the warming in the cold cloud surrounding the eye.

The system continues to lie under northeasterly shear [CIMSS analysed shear at 28/0900 UTC was 15 knots from the east-northeast] though this shear appears to be in the upper levels [above 400hPa]. More favourable conditions are expected for the system overnight with a continued decreasing trend in shear, and system motion is likely to slow. Intensification is still expected over the next 12 to 24 hours. The system is likely to be slow moving for a period on Monday before taking a track to the southeast on Tuesday.

SST's are cooler to the south, with sub 26 degrees south of about 18S. This could limit development from Monday and then assist in the system weakening as it moves further south. The circulation is expected to remain at TC strength over open waters for the next 5-7 days.


Copyright Commonwealth of Australia
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The next bulletin for this system will be issued by: 28/1930 UTC.
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