SIO: MARIAN - Post-Tropical

[Nancy Smar]

At 2pm WST 23 February a weak tropical low (15U) was located near 13.3S 120.9E, about 540 kilometres north northwest of Broome. It is expected to track to the west and gradually develop, and by Friday there is a high chance of it reach tropical cyclone intensity.
It will move to the south of Christmas Island during Friday, and although it is unlikely to produce gales at the Island, it will result in an freshening of the northwesterly monsoonal flow, and an increase in shower and thunderstorm activity. It should then continue to develop over the weekend, well the the northwest of mainland WA.

Likelihood of this system being a tropical cyclone in the Western Region on:
Wednesday:Very Low
Thursday:Moderate
Friday:High

[Nancy Smar]

98S INVEST 210223 0600 13.6S 122.5E SHEM 15 0

[Subtrop]

(1) AN AREA OF CONVECTION (INVEST 98S) HAS PERSISTED NEAR
13.7S 116.3E, APPROXIMATELY 526 NM NORTH-NORTHEAST OF LEARMONTH,
AUSTRALIA. ANIMATED ENHANCED INFRARED IMAGERY AND A 231900Z GMI
89GHZ MICROWAVE IMAGE DEPICT A CONSOLIDATING LOW LEVEL CIRCULATION
CENTER WITH PERSISTENT DEEP CONVECTION. RADIAL OUTFLOW, LOW VERTICAL
WIND SHEAR (10-15KTS) AND WARM SEA SURFACE TEMPERATURES (29-30C)
CREATE FAVORABLE CONDITIONS FOR FURTHER DEVELOPMENT. GLOBAL MODELS
INDICATE INVEST 98S WILL TRACK WESTWARD AND INTENSIFY QUICKLY OVER
THE NEXT 36-48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED
AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE
NEAR 1002 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS MEDIUM.

[aspen]

The JTWC has only just upgraded this to a bona-fide TC, but just looking at its satellite presentation suggests it has been one for a while, and the agencies are lagging behind in intensity — again.

[Subtrop]

IDW24000
Australian Bureau of Meteorology
Tropical Cyclone Warning Centre

TROPICAL CYCLONE INFORMATION BULLETIN
Issued at 2:52 pm WST on Friday 26 February 2021

Tropical Cyclone Marian (Category 1) was located at 2:00 pm AWST near 14.5S
98.9E,

that is 340 km southeast of Cocos Island and 860 km west southwest of Christmas
Island and moving west southwest at 31 kilometres per hour.
Tropical Cyclone Marian will continue tracking to the west southwest passing
south of Cocos (Keeling) Islands tonight but not having any direct impact upon
the islands.

During Saturday it is likely to be moving away from the islands.

The next Information Bulletin will be issued at 9 pm AWST.

[Iceresistance]

Don't forget the JTWC!

[mrbagyo]

[cycloneye]

 https://twitter.com/jnmet/status/1365672425434808325

[aspen]

Marian is having a really hard time getting a nice, solid eyewall, both on IR and microwave imagery. The latter shows that the SE quadrant of the eyewall is much weaker, probably due to dry air eroding at it.

[Subtrop]

IDW24000
Australian Bureau of Meteorology
Tropical Cyclone Warning Centre

TROPICAL CYCLONE INFORMATION BULLETIN
Issued at 8:30 am WST on Sunday 28 February 2021

Severe Tropical Cyclone Marian (Category 3) was located at 8:00 am AWST near
16.8S 92.2E, that is 720 km southwest of Cocos Island and moving southwest at
13 kilometres per hour.
Severe Tropical Cyclone Marian will continue tracking to the southwest over the
Indian Ocean during Sunday and Monday. On Tuesday it is expected to start
moving to the southeast and start a gradual weakening trend.

The next Information Bulletin will be issued at 3 pm AWST.

[aspen]

This is the best Marian has looked so far, although a microwave pass from 21z still showed a weak and dry SE side. The 00z best track intensity is 75 kt.

[mrbagyo]

[Subtrop]

22S MARIAN 210228 1200 17.4S 91.3E SHEM 100 952