Aust: Tropical Low 10U 21
From
Weather Alert@21:1/175 to
All on Fri Jan 22 00:04:00 2021
AXAU02 APRF 211916
IDW27700
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1915 UTC 21/01/2021
Name: Tropical Low
Identifier: 10U
Data At: 1800 UTC
Latitude: 12.9S
Longitude: 97.6E
Location Accuracy: within 20 nm [35 km]
Movement Towards: southeast [128 deg]
Speed of Movement: 2 knots [5 km/h]
Maximum 10-Minute Wind: 40 knots [75 km/h]
Maximum 3-Second Wind Gust: 55 knots [100 km/h]
Central Pressure: 994 hPa
Radius of 34-knot winds NE quadrant: 80 nm [150 km]
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant: 80 nm [150 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:
Radius of Maximum Winds:
Dvorak Intensity Code: T1.5/2.0/S0.0/24HRS STT:W0.5/06HRS
Pressure of outermost isobar: 1008 hPa
Radius of outermost closed isobar: 240 nm [445 km]
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+06: 22/0000: 13.1S 97.7E: 035 [070]: 040 [075]: 994
+12: 22/0600: 13.3S 97.8E: 050 [090]: 035 [065]: 996
+18: 22/1200: 13.5S 98.0E: 055 [105]: 035 [065]: 996
+24: 22/1800: 13.8S 98.2E: 065 [120]: 035 [065]: 996
+36: 23/0600: 14.6S 98.3E: 075 [140]: 035 [065]: 996
+48: 23/1800: 15.6S 98.5E: 095 [175]: 035 [065]: 994
+60: 24/0600: 16.6S 98.2E: 110 [200]: 035 [065]: 994
+72: 24/1800: 17.4S 98.0E: 120 [225]: 035 [065]: 994
+96: 25/1800: 18.8S 98.3E: 155 [290]: 040 [075]: 992
+120: 26/1800: 18.8S 97.6E: 185 [340]: 045 [085]: 990
REMARKS:
The low level centre remains well exposed from the CDO, and as a result the position accuracy is good. An ASCAT pass from 1529UTC showed gales are present within about 80nm of the system centre in the northern semicircle, with maximum winds of 40 knots. Winds in the southern semicircle are 25 knots or less.
Tropical low 10U continues to show a weakening trend over the last 6 hours with deep convection remaining displaced well to the northwest of the low level centre. A time averaged shear pattern yields a DT of 1.5-2.0. Dvorak assessment based on MET and PAT gives an FT of 1.5. CI was held at 2.0 during weakening.
10U is in an area of moderate to strong vertical wind shear on the northern side
of the upper ridge, under a divergent easterly flow of around 25kt at 200hPa. The middle level circulation is weak, and displaced well to the west of the low level circulation. As a result, the system will likely take some time to re-consolidate into a deep circulation [if it does at all], and the forecast for development into a tropical cyclone has been delayed until Sunday.
A trough at 700hPa over the southern Indian Ocean appears to be guiding this system in a south southeasterly direction over the next 48 hours. As the system moves into an area of lower shear, the vertical alignment should improve, and from Sunday it is forecast to move southerly under the influence of a mid level ridge developing to the east of the system. On Monday a mid level trough passes to the south of the system, and in some of the guidance this results in an easterly movement, whereas other guidance has it slow moving. From Tuesday a mid
level ridge should develop to the south of the system, pushing it towards the west.
If the system does manage to regain its vertical structure as it moves south, then the environment will be marginally favourable for development from Sunday, with decreased wind shear, sufficiently warm SSTs, and potential poleward outflow from an upper trough to the south.
Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 22/0130 UTC.
ia
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From
Dumas Walker@21:1/175 to
All on Fri Jan 22 00:04:00 2021
AXAU02 APRF 211916
IDW27700
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1915 UTC 21/01/2021
Name: Tropical Low
Identifier: 10U
Data At: 1800 UTC
Latitude: 12.9S
Longitude: 97.6E
Location Accuracy: within 20 nm [35 km]
Movement Towards: southeast [128 deg]
Speed of Movement: 2 knots [5 km/h]
Maximum 10-Minute Wind: 40 knots [75 km/h]
Maximum 3-Second Wind Gust: 55 knots [100 km/h]
Central Pressure: 994 hPa
Radius of 34-knot winds NE quadrant: 80 nm [150 km]
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant: 80 nm [150 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:
Radius of Maximum Winds:
Dvorak Intensity Code: T1.5/2.0/S0.0/24HRS STT:W0.5/06HRS
Pressure of outermost isobar: 1008 hPa
Radius of outermost closed isobar: 240 nm [445 km]
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+06: 22/0000: 13.1S 97.7E: 035 [070]: 040 [075]: 994
+12: 22/0600: 13.3S 97.8E: 050 [090]: 035 [065]: 996
+18: 22/1200: 13.5S 98.0E: 055 [105]: 035 [065]: 996
+24: 22/1800: 13.8S 98.2E: 065 [120]: 035 [065]: 996
+36: 23/0600: 14.6S 98.3E: 075 [140]: 035 [065]: 996
+48: 23/1800: 15.6S 98.5E: 095 [175]: 035 [065]: 994
+60: 24/0600: 16.6S 98.2E: 110 [200]: 035 [065]: 994
+72: 24/1800: 17.4S 98.0E: 120 [225]: 035 [065]: 994
+96: 25/1800: 18.8S 98.3E: 155 [290]: 040 [075]: 992
+120: 26/1800: 18.8S 97.6E: 185 [340]: 045 [085]: 990
REMARKS:
The low level centre remains well exposed from the CDO, and as a result the position accuracy is good. An ASCAT pass from 1529UTC showed gales are present within about 80nm of the system centre in the northern semicircle, with maximum winds of 40 knots. Winds in the southern semicircle are 25 knots or less.
Tropical low 10U continues to show a weakening trend over the last 6 hours with deep convection remaining displaced well to the northwest of the low level centre. A time averaged shear pattern yields a DT of 1.5-2.0. Dvorak assessment based on MET and PAT gives an FT of 1.5. CI was held at 2.0 during weakening.
10U is in an area of moderate to strong vertical wind shear on the northern side
of the upper ridge, under a divergent easterly flow of around 25kt at 200hPa. The middle level circulation is weak, and displaced well to the west of the low level circulation. As a result, the system will likely take some time to re-consolidate into a deep circulation [if it does at all], and the forecast for development into a tropical cyclone has been delayed until Sunday.
A trough at 700hPa over the southern Indian Ocean appears to be guiding this system in a south southeasterly direction over the next 48 hours. As the system moves into an area of lower shear, the vertical alignment should improve, and from Sunday it is forecast to move southerly under the influence of a mid level ridge developing to the east of the system. On Monday a mid level trough passes to the south of the system, and in some of the guidance this results in an easterly movement, whereas other guidance has it slow moving. From Tuesday a mid
level ridge should develop to the south of the system, pushing it towards the west.
If the system does manage to regain its vertical structure as it moves south, then the environment will be marginally favourable for development from Sunday, with decreased wind shear, sufficiently warm SSTs, and potential poleward outflow from an upper trough to the south.
Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 22/0130 UTC.
ia
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)