IDQ20018
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 0143 UTC 05/03/2021
Name: Severe Tropical Cyclone Niran
Identifier: 17U
Data At: 0000 UTC
Latitude: 16.6S
Longitude: 154.4E
Location Accuracy: within 10 nm [20 km]
Movement Towards: east southeast [114 deg]
Speed of Movement: 20 knots [37 km/h]
Maximum 10-Minute Wind: 90 knots [165 km/h]
Maximum 3-Second Wind Gust: 125 knots [230 km/h]
Central Pressure: 954 hPa
Radius of 34-knot winds NE quadrant: 180 nm [335 km]
Radius of 34-knot winds SE quadrant: 90 nm [165 km]
Radius of 34-knot winds SW quadrant: 110 nm [205 km]
Radius of 34-knot winds NW quadrant: 150 nm [280 km]
Radius of 48-knot winds NE quadrant: 70 nm [130 km]
Radius of 48-knot winds SE quadrant: 40 nm [75 km]
Radius of 48-knot winds SW quadrant: 40 nm [75 km]
Radius of 48-knot winds NW quadrant: 50 nm [95 km]
Radius of 64-knot winds: 25 nm [45 km]
Radius of Maximum Winds: 10 nm [20 km]
Dvorak Intensity Code: T5.5/5.5/D1.0/24HRS SST:D0.5/06HRS
Pressure of outermost isobar: 1000 hPa
Radius of outermost closed isobar: 180 nm [335 km]
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+06: 05/0600: 17.5S 156.2E: 030 [055]: 100 [185]: 943
+12: 05/1200: 18.5S 158.2E: 045 [085]: 105 [195]: 935
+18: 05/1800: 19.6S 160.4E: 060 [110]: 105 [195]: 935
+24: 06/0000: 20.7S 162.4E: 075 [135]: 095 [175]: 944
+36: 06/1200: 22.9S 167.2E: 095 [175]: 080 [150]: 957
+48: 07/0000: 25.3S 172.3E: 125 [235]: 065 [120]: 969
+60: 07/1200: 27.6S 178.1E: 150 [280]: 050 [095]: 980
+72: 08/0000: 29.6S 177.0W: 200 [365]: 045 [085]: 981
+96: 09/0000: : : :
+120: 10/0000: : : :
REMARKS:
Severe Tropical Cyclone Niran continues to move quickly to the east southeast
well off the Queensland coast. Recent microwave imagery SSMIS at 2020UTC and EIR
imagery show a clear and tight eye emerging by 1900UTC. Deep convection has been
sustained around the eye for the last 5 hours.
Dvorak yields an eye pattern with a MG/CMG eye temperature and a White
surrounding temperature yielding a DT of 6.0. However the eye temperature and
surrounding temperature has been fluctuating over the last 6 hours with a 3 hour
trend DT of 5.5. PT and MET [D1.0/24HRS] agree with 5.5. FT based on MET. CI is
5.5 with an intensity of 90 knots. ADT guidance does fluctuate from 85 knot to
150 knots [CIMSS AMSU 2249 UTC], however some are not using an eye pattern and
may be under estimating the intensity. SATCON estimates 119 knots [1-min mean]
at 2249 UTC 4 March.
The NE'ly shear has decreased to low to moderate [10KT] in the CIMMS 0000 UTC
analysis. CIMSS satellite winds indicate dual outflow channels across the
system; sea surface temperatures are above 29C along the forecast track. The
easterly shear is expected to ease further and shift to be northwesterly in
time. Hence, intensification is forecast to continue over the next 12 to 24
hours.
There is high confidence that the system will maintain an east-southeast track
away from the Queensland coast over the next few days before approaching New
Caledonia over the weekend. This motion will continue as a result of an upper
trough that is currently moving across eastern Australia. In the longer term, a
combination of increased vertical wind shear associated with this upper trough
and cooler sea surface temperatures should lead to a gradual weakening of the
system as it moves further across the Coral Sea into the weekend.
Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 05/0730 UTC.
H. REMARKS: 07A/PBO IRREG EYE/ANMTN. DG EYE SURROUNDED BY W
YIELDS AN E# OF 6.0. ADDED 0.5 EYE ADJUSTMENT FOR CMG, TO YIELD
A DT OF 6.5. MET/PT AGREE. DBO DT.
