BoM 18Z降TD，但還沒登陸。

IDD20020
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - NORTHERN REGION
Issued by DARWIN TROPICAL CYCLONE WARNING CENTRE
at: 2010 UTC 20/02/2017
Name: Ex-Tropical Cyclone Alfred
Identifier: 19U
Data At: 1800 UTC
Latitude: 16.1S
Longitude: 137.7E
Location Accuracy: within 30 nm [55 km]
Movement Towards: southeast [130 deg]
Speed of Movement: 2 knots [4 km/h]
Maximum 10-Minute Wind: 30 knots [55 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 999 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:   
Radius of Maximum Winds:   
Dvorak Intensity Code: T1.5/2.5/W1.5/24HRS
Pressure of outermost isobar: 1006 hPa
Radius of outermost closed isobar: 120 nm [220 km]
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
[UTC]        : degrees     :      nm  [km]: knots[km/h]: hPa
+06:  21/0000: 16.3S 137.9E:     030 [055]:  030  [055]: 1000
+12:  21/0600: 16.4S 137.9E:     030 [055]:  030  [055]: 1000
+18:  21/1200: 16.5S 137.9E:     030 [055]:  030  [050]: 1000
+24:  21/1800: 16.5S 137.9E:     040 [075]:  025  [045]: 1000
+36:  22/0600: 16.4S 137.6E:     060 [110]:  025  [045]: 1000
+48:  22/1800: 16.1S 136.7E:     080 [150]:  025  [045]: 1001
+60:  23/0600: 15.8S 135.2E:     100 [185]:  025  [045]: 1003
+72:  23/1800: 15.4S 133.0E:     110 [205]:  020  [040]: 1004
+96:  24/1800: 14.9S 127.9E:     150 [280]:  020  [035]: 1004
+120: 25/1800: 14.6S 124.5E:     190 [350]:  020  [035]: 1004
REMARKS:
The centre was located using a combination of a 1300UTC ASCAT pass, surface
observations and satellite imagery. Animated near-infrared shows that a well
defined circulation still persists over the far southern Gulf of Carpentaria.

Winds at Centre Island and Morninton Island during the last 6 hours have
reported winds of 15-20 knots and easing. The ASCAT pass 1300UTC showed broad
area of 25-30 knots and marginally 35 knots around the system. Recent satellite
imagery has shown dry air dominating the environment and an absence of deep
convection near the LLCC for more than 6 hours. FT=1.5, based on MET, while CI
is maintained  at 2.5.

As such, Tropical Cyclone Alfred was downgraded to a tropical low at 1800UTC.

The tropical cyclone has moved slowly southeast under the influence of a
mid-level ridge to the NE and a mid-latitude trough to the southeast. A ridge
building to the south is expected to slow the southeast movement today, causing
the system to stall close to the coast.

Vertical wind shear is around 10-15 knots and is forecast to remain at this
amount during the next day or two. Outflow is good in the southern semicircle
due to an upper trough to the west. So there is the potential for renewed bursts
of convection to develop near the LLCC while it remains over water. However
significant dry air in the western and northern sectors of the circulation,
together with land interaction means there is now only a low chance the system
could redevelop into a tropical cyclone.

From later Tuesday and on Wednesday the remnant tropical low is forecast to
track towards the west over land south of the Top End as southeasterly steering
winds establish.

Copyright Commonwealth of Australia
==
There will be no further bulletins for this system unless it reintensifies.

22Z命名Alfred

Details of Tropical Cyclone Alfred at 6:30 am ACST [7:00 am AEST]:
Intensity: Category 1, sustained winds near the centre of 65 kilometres per hour with wind gusts to 95 kilometres per hour.

Location: within 45 kilometres of 15.0 degrees South 137.3 degrees East, estimated to be 160 kilometres northeast of Borroloola and 160 kilometres southeast of Alyangula.

Movement: southeast at 12 kilometres per hour.

Tropical cyclone Alfred has formed in the southwest Gulf of Carpentaria and has recently commenced a track towards the southeast. Heavy rain and squally winds associated with the system are likely. The cyclone is forecast to weaken in the southern Gulf of Carpentaria prior to landfall during Tuesday.

JTWC 20Z把評級降為Medium

(2) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 19.9S
145.7W, IS NOW LOCATED NEAR 21.4S 145.0W, APPROXIMATELY 315 NM
SOUTHEAST OF PAPEETE, TAHITI, FRENCH POLYNESIA. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS A DEFINED, PARTIALLY EXPOSED LOW-
LEVEL CIRCULATION CENTER (LLCC) WITH PERSISTENT DEEP CONVECTION OVER
THE EASTERN SEMI-CIRCLE. A 171214Z SSMI 85GHZ IMAGE SHOWS SHALLOW
BANDING WRAPPING INTO AN ORGANIZED LLCC WITH DEEP CONVECTIVE BANDING
OVER THE EASTERN SEMI-CIRCLE. THIS SYSTEM IS LOCATED ALONG THE
LEADING EDGE OF AN UPPER-LEVEL TROUGH WITH STRONG DIFFLUENCE FUELING
THE PERSISTENT CONVECTION. THE SYSTEM IS LOCATED UNDER STRONG
VERTICAL WIND SHEAR (20-30 KNOTS). THE GLOBAL MODELS INDICATE A
SOUTHWARD TRACK AND INTENSIFICATION TREND AS THE SYSTEM MOVES UNDER
THE UPPER-LEVEL TROUGH AND TRANSITIONS TO A FULLY SUBTROPICAL
CYCLONE WITHIN THE NEXT ONE TO TWO DAYS. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS MEDIUM.

神奇的預測路徑

稍早中心通過莫寧頓半島機場附近
看似實測未達標所以沒升 不過也差一點點了

系統中心已經登陸昆士蘭州，BoM編號19U，看好出海後能至少達到二級熱帶氣旋強度。

IDD20020
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - NORTHERN REGION
Issued by DARWIN TROPICAL CYCLONE WARNING CENTRE
at: 0152 UTC 17/02/2017
Name: Tropical Low  
Identifier: 19U
Data At: 0000 UTC
Latitude: 16.8S
Longitude: 138.5E
Location Accuracy: within 10 nm [20 km]
Movement Towards: west southwest [252 deg]
Speed of Movement: 7 knots [12 km/h]
Maximum 10-Minute Wind: 30 knots [55 km/h]
Maximum 3-Second Wind Gust: 50 knots [95 km/h]
Central Pressure: 998 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:   
Radius of Maximum Winds:   
Dvorak Intensity Code: T2.5/2.5/D1.0/24HRS
Pressure of outermost isobar: 1008 hPa
Radius of outermost closed isobar: 80 nm [150 km]
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
[UTC]        : degrees     :      nm  [km]: knots[km/h]: hPa
+06:  17/0600: 17.0S 138.3E:     030 [055]:  025  [045]: 1000
+12:  17/1200: 16.9S 138.0E:     050 [095]:  025  [045]: 1002
+18:  17/1800: 16.7S 137.5E:     070 [130]:  025  [045]: 1002
+24:  18/0000: 16.4S 137.3E:     090 [165]:  030  [055]: 1000
+36:  18/1200: 15.9S 137.4E:     130 [240]:  030  [055]:  998
+48:  19/0000: 15.7S 138.1E:     170 [315]:  045  [085]:  994
+60:  19/1200: 15.3S 139.1E:     220 [405]:  055  [100]:  988
+72:  20/0000: 15.2S 139.5E:     270 [500]:  060  [110]:  983
+96:  21/0000: 16.0S 139.7E:     340 [620]:  045  [085]:  993
+120: 22/0000: 16.5S 139.5E:     400 [740]:  035  [065]: 1000
REMARKS:
The tropical low is crossing the coast in the southern Gulf of Carpentaria.
Mornington Island radar has shown that convection is still tightly wrapped
around the low level centre, although cloud top temperatures have warmed
significantly. Scatterometer winds at 1148UTC last night indicated an area of
marginal gale force winds on the eastern flank of the system and gales were
observed briefly at Mornington Island early in the morning.

The latest Dvorak analysis was based on a curved band pattern with a 0.5 degree
wrap, giving a DT of 2.5. MET and PAT 2.0 and 2.5 respectively. FT based on DT
as it appeared fairly clear.

The CIMMS satellite winds indicate that the system lies in an environment
favourable for development with low vertical wind shear and dual outflow
channels evident. Sea surface temperatures are sufficiently warm at 30 degrees
around the southern Gulf of Carpentaria waters. As a result, it is anticipated
that the system may form into a tropical cyclone if it moves back over water and
that it could reach category 2 intensity on Sunday, but this will be highly
dependent on the system taking a track over water during the next 24 to 48
hours.

The recent movement of the system has been towards the southwest, presumably
under the influence of a mid-level ridge situated to the northeast. It is
expected that the system will start to track westwards as a middle level ridge
builds to the south, turning towards the northwest on Saturday when an
amplifying upper trough from the southwest breaks down the steering influence,
resulting in a recurving of the system towards the east.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 17/0800 UTC by Darwin TCWC.

JTWC 18Z發佈TCFA

WTPS21 PGTW 161830
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
A 200 NM RADIUS OF 16.4S 139.2E WITHIN THE NEXT 12 TO 24 HOURS.
AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL
CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO
BE 25 TO 30 KNOTS. METSAT IMAGERY AND RADAR DATA AT 161800Z
INDICATE THAT A CIRCULATION CENTER IS LOCATED NEAR 16.4S 139.2E.
THE SYSTEM IS MOVING SOUTH-SOUTHWESTWARD AT 04 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91P) PREVIOUSLY LOCATED
NEAR 15.8S 138.6E IS NOW LOCATED NEAR 16.4S 139.2E, APPROXIMATELY
16NM NORTH OF MORNINGTON ISLAND, AUSTRALIA. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS A SLIGHT WEAKENING IN DEEP
CONVECTION, HOWEVER, RADAR IMAGERY FROM THE MORNINGTON ISLAND RADAR
SHOWS A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER WITH BANDING
WRAPPING IN FROM THE NORTH. SURFACE OBSERVATIONS FROM MORNINGTON
ISLAND SHOW EAST-SOUTHEASTERLY WINDS AT 20 TO 25 KNOTS GUSTING TO 30
TO 35 KNOTS WITH A SLP VALUE OF 1000.3MB AND A 24-HOUR SLP DECREASE
OF 5.9MB. ENVIRONMENTAL CONDITIONS ARE DYNAMICALLY FAVORABLE FOR
FURTHER DEVELOPMENT WITH DUAL CHANNEL OUTFLOW, LOW TO MODERATE
VERTICAL WIND SHEAR AND WARM SST (29 TO 30C). MODEL GUIDANCE DEPICTS
QUASI-STATIONARY MOTION WITH CONTINUED DEVELOPMENT OVER THE SOUTHERN
GULF OF CARPENTARIA WITHIN THE NEXT DAY OR TWO. HOWEVER, SOME MODELS
SHOW THE DISTURBANCE MOVING INLAND AND DELAYING FURTHER
INTENSIFICATION. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25
TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000
MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.

JTWC提升評級至Medium

(2) THE AREA OF CONVECTION (INVEST 91P) PREVIOUSLY LOCATED
NEAR 15.8S 138.6E IS NOW LOCATED NEAR 16.1S 139.6E, APPROXIMATELY
20NM NORTH-NORTHEAST OF MORNINGTON ISLAND, AUSTRALIA. ANIMATED
ENHANCED INFRARED SATELLITE IMAGERY DEPICTS DEEP CONVECTION
DECREASING IN AREAL EXTENT, HOWEVER, RADAR IMAGERY FROM THE
MORNINGTON ISLAND RADAR SHOWS A CONSOLIDATING LOW-LEVEL CIRCULATION
CENTER WITH BANDING WRAPPING INTO A WELL-DEFINED CENTER. A 160914Z
SSMIS 91GHZ IMAGE SHOWS A COMPACT SYSTEM WITH CONVECTIVE BANDING
WRAPPING INTO A WEAK MICROWAVE EYE FEATURE. SURFACE OBSERVATIONS
FROM MORNINGTON ISLAND SHOW SOUTHEASTERLY WINDS AT 15 TO 20 KNOTS
GUSTING TO 25 TO 30 KNOTS WITH A SLP VALUE OF 1004.3MB AND A 24-HOUR
SLP DECREASE OF 2.6MB. IF THIS AREA REMAINS OVER WATER,
ENVIRONMENTAL CONDITIONS ARE DYNAMICALLY FAVORABLE FOR FURTHER
DEVELOPMENT WITH GOOD DIFFLUENCE ALOFT, LOW TO MODERATE VERTICAL
WIND SHEAR AND WARM SST (29 TO 30C). THE GLOBAL MODELS DEPICT A
QUASI-STATIONARY MOTION AND SLOW DEVELOPMENT AS THE SYSTEM
TRACKS ALONG THE SOUTHERN GULF OF CARPENTARIA OVER THE NEXT TWO
DAYS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM.

BoM非常看好發展

Potential Cyclones:

A tropical low over the southern Gulf of Carpentaria is expected to be slow moving during the next few days with an increasing risk of a tropical cyclone forming.

Likelihood of a tropical cyclone in the Northern Region on:
Friday : Low.
Saturday:Moderate.
Sunday:High.