Australian Government Bureau of Meteorology
Northern Territory
Tropical Cyclone Warning Centre
Media: The Standard Emergency Warning Signal should NOT be used with this
warning.
PRIORITY
TROPICAL CYCLONE WATCH
TROPICAL CYCLONE ADVICE NUMBER 1
Issued at 4:55 pm CST on Wednesday 21 December 2011
A Cyclone WATCH has been declared for a developing tropical low for coastal
areas from Dundee Beach to Nhulunbuy, including Darwin.
At 3:30 pm CST a Tropical Low was estimated to be
175 kilometres north of Croker Island and
350 kilometres north northeast of Darwin and
moving west northwest at 4 kilometres per hour away from the coast.
A tropical cyclone is expected to develop late on Friday or during Saturday
north of the Top End. GALES are not expected in coastal areas in the next 24
hours, however gales could develop later.
The Territory Controller advises communities under Watch that now is the time
to put together your emergency kit, clear your yards and balconies, and
commence home shelter preparations.
Residents of Darwin and Rural Area are advised that if you DO NOT have
accommodation constructed to the Building Code or are unsure of your present
accommodation you should determine which public emergency shelter to use. This
advice is issued to allow you sufficient time in which to take the necessary
precautions before winds reach a dangerous level.
Details of Tropical Low at 3:30 pm CST:
.Centre located near...... 9.6 degrees South 132.3 degrees East
.Location accuracy........ within 120 kilometres
.Recent movement.......... towards the west northwest at 4 kilometres per hour
.Wind gusts near centre... 85 kilometres per hour
.Severity category........ below cyclone intensity
.Central pressure......... 1000 hectoPascals
Please ensure that neighbours have heard and understood this message,
particularly new arrivals or those who may not fully understand English.
The next advice will be issued by 11:00 pm CST Wednesday 21 December.


IDD20020
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - NORTHERN REGION
Issued by DARWIN TROPICAL CYCLONE WARNING CENTRE
at: 0739 UTC 21/12/2011
Name: Tropical Low
Identifier: 04U
Data At: 0600 UTC
Latitude: 9.6S
Longitude: 132.3E
Location Accuracy: within 65 nm [120 km]
Movement Towards: west northwest [300 deg]
Speed of Movement: 2 knots [4 km/h]
Maximum 10-Minute Wind: 20 knots [35 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 1000 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant:
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:
Dvorak Intensity Code: Not Assessed
Pressure of outermost isobar: 1006 hPa
Radius of outermost closed isobar: 120 nm [220 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 21/1800: 9.3S 131.5E: 095 [175]: 025 [045]: 1001
+24: 22/0600: 8.8S 131.9E: 125 [230]: 030 [055]: 1000
+36: 22/1800: 9.2S 132.4E: 160 [290]: 030 [055]: 1000
+48: 23/0600: 9.8S 132.7E: 190 [350]: 035 [065]: 997
+60: 23/1800: 10.3S 132.6E: 240 [440]: 045 [085]: 991
+72: 24/0600: 10.5S 131.9E: 285 [530]: 055 [100]: 985
REMARKS:
Surface position estimated on strongest region of vorticity associated with
monsoonal westerlies - position estimate is therefore poor.
Upper level trough passage to south in 24 to 48 hours, together with low level
easterly burst is expected to produce strongly favourable upper conditions
suited for rapid development of a small system.
Widely varying model guidance, with little intra run or intra model consistency,
suggests a conservative foreacst policy is warranted. Longer term motion could
be ESE driven by capture of the mid to upper level trough, or by subsequent post
trough ridging, forcing a WSW track.
No Dvorak assessment undertaken.
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