2014/15 South Pacific & Coral Sea TC Season

[Nev]

The Tropical Cyclone Season officially began in our neck of the woods on Nov 1st, so thought it might be worth starting a thread about any potential TC development.

The likelihood of at least a weak El Nino this summer means a slight increase for the chances of TC development in the South Pacific, but more likely around or east of the dateline.

[Nev]

Currently there is an interesting area of convection about 400 km N of Samoa (NE of Fiji) that's been flaring up nicely overnight and perhaps worth keeping an eye on in the coming days…

Comments from JTWC yesterday evening…

ABPW10 PGTW 230600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/230600Z-240600ZNOV2014//
RMKS/
…
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 8.2S
177.1W, IS NOW LOCATED NEAR 11.5S 174.4W, APPROXIMATELY 204 NM NORTH
OF PAGO PAGO, AMERICAN SAMOA. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS UNORGANIZED FLARING CONVECTION ASSOCIATED WITH AN
ELOGATED LOW-LEVEL CIRCULATION CENTER. A 230354Z NOAA-19 MICROWAVE
IMAGE REVEALS VERY FRAGMENTED CONVECTIVE BANDING ON THE EASTERN SIDE
BROADLY WRAPPING INTO THE CENTER. ALSO, A CIMMS 230300Z 850MB
RELATIVE VORTICITY PRODUCT SHOWS AN ELONGATED VORTICITY SIGNATURE.
UPPER-LEVEL ANALYSIS INDICATES THE DISTURBANCE IS LOCATED NORTH OF
THE RIDGE AXIS IN A FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (05
TO 15 KNOT) VERTICAL WIND SHEAR AND EXCELLENT POLEWARD OUTFLOW.
ADDITIONALLY, SEA SURFACE TEMPERATURES WITH A RANGE OF 26 TO 28
DEGRESS CELCIUS IN THE AREA ARE FAVORABLE FOR DEVELOPMENT. 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 REMAINS LOW.

And from Fiji Met…

Tropical Disturbance Summary For area Equator to 25S, 160E to 120W
ISSUED FROM RSMC NADI Nov 23/0904 UTC 2014 UTC.

TROPICAL DEPRESSION 01F [1005HPA] ANALYSED NEAR 9.6S 177.1W AT
230600UTC. SLOW MOVING. POSITION POOR BASED ON MTSAT IR IMAGERY AND
PERIPHERAL SURAFCE OBSERVATIONS. SST AROUND 30 DEGREES CELCIUS.

CONVECTION PERSISTENT PAST 24 HOURS. ORGANISATION HAS SLIGHTLY
IMPROVED PAST 24 HOURS. SYSTEM LIES UNDER AN UPPER DIFFLUENT REGION
IN A LOW SHEARED ENVIRONMENT. CYCLONIC CIRCULATION EXTENDS UPTO
500HPA.

GLOBAL MODELS HAVE PICKED UP THE SYSTEM AND MOVE IT SOUTHEASTWARDS
WITH LITTLE INTENSIFICATION.

THE POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN
THE NEXT 24-48 HOURS IS LOW TO MODERATE.

NO OTHER SIGNIFICANT TROPICAL DISTURBANCE ANALYSED OR FORECAST IN THE
AREA.

[Nev]

Both JTWC and Nadi now have a moderate chance of seeing the Sth Pacific Season's first TC forming around the Cook Islands area in the next day or two…

ABPW10 PGTW 231200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS REISSUED/231200Z-240600ZDEC2014//
RMKS/
…
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 14.4S
160.2W, IS NOW LOCATED NEAR 13.7S 159.9W, APPROXIMATELY 495 NM WEST-
NORTHWEST OF BORA BORA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS BUILDING DEEP CONVECTION DISPLACED TO NORTHEAST OF A POORLY
DEFINED LOW LEVEL CIRCULATION CENTER (LLCC). HOWEVER, A 230843Z
ASCAT PASS REVEALED AN INCREASE IN CONSOLIDATION OF THE LLCC AS WIND
SPEEDS HAVE INCREASED ALONG THE PERIPHERIES WITH THE MAX WINDS
LOCATED IN THE DEEP CONVECTION AND DISPLACED FROM THE CENTER BY
APPROXIMATELY 60 NM. UPPER LEVEL ANALYSIS REVEALS A FAVORABLE
ENVIRONMENT HAS PERSISTED WITH LOW TO MODERATE VERTICAL WIND SHEAR
AND DIVERGENT OUTFLOW. 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 UPGRADED TO MEDIUM.
(2) NO OTHER SUSPECT AREAS.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA 2.B.(1) TO
MEDIUM.//
NNNN

TROPICAL DISTURBANCE ADVISORY NUMBER A4 ISSUED FROM RSMC NADI
Dec 23/1328 UTC 2014 UTC.

TROPICAL DEPRESSION 03F CENTER [1000HPA] ANALYSED NEAR 12.6S 159.2W
AT 231200UTC. DEPRESSION MOVING NORTHEAST AT ABOUT 3 KNOTS. MAXIMUM
10-MINUTE AVERAGE WINDS NEAR THE CENTRE ESTIMATED AT ABOUT 25 KNOTS.

OVERALL ORGANISATION WAS GOOD IN THE LAST 24 HOURS. DEEP CONVECTION
HAS INCREASED IN THE PAST 6 HOURS BUT REMAINS TO THE NORTHEAST OF THE
SYSTEM. SYSTEM LIES JUST TO THE SOUTH OF AN UPPER DIFFLUENT REGION IN
A LOW TO MODERATE SHEARED ENVIRONMENT. OUTFLOW GOOD TO THE EAST AND
NORTH BUT RESTRICTED ELSEWHERE. CYCLONIC CIRCULATION EXTENDS UPTO
500HPA. SYSTEM IS BEING STEERED TO THE NORTHEAST BY WEST-SOUTHWEST
DEEP LAYER MEAN WIND. SST AROUND 29 DEGREES CELCIUS.

GLOBAL MODELS AGREE ON A EAST-NORTHEAST MOVEMENT THEN SOUTHEAST WITH
FURTHER INTENSIFICATION.

POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN THE
NEXT 24 TO 48 HOURS IS MODERATE.

THE NEXT TROPICAL DISTURBANCE ADVISORY ON TD03F WILL BE ISSUED AT OR
AROUND 232000UTC

[Manukau heads obs]

typicaly El Nino will see TC form futher east...as is the case here...

[Nev]

Yep. There's also an area of interest NE of Fiji that might be worth keepin an eye on.

JTWC have issued a Formation Alert for the Cooks/Tahiti area…

WTPS21 PGTW 231700
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 13.4S 159.6W TO 16.2S 156.8W
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 AT
231630Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 13.8S
159.0W. THE SYSTEM IS MOVING EASTWARD AT 12 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 13.7S
159.9W IS NOW LOCATED NEAR 13.8S 159.0W, APPROXIMATELY 445 NM WEST-
NORTHWEST OF BORA BORA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH AN
AREA OF INTENSE DEEP CONVECTION OVER THE EASTERN SEMI-CIRCLE OF THE
LLCC. A 231500Z TRMM 37 GHZ IMAGE SHOWS PERSISTENT DEEP CONVECTIVE
BANDING OVER THE NORTHERN QUADRANT WRAPPING INTO THE EASTERN
QUADRANT OF THE LLCC WITH IMPROVED SHALLOW BANDING ELSEWHERE. A
230843Z ASCAT IMAGE REVEALS A SYMMETRIC CIRCULATION WITH 30 TO 35
KNOT WINDS DISPLACED OVER THE NORTHEAST QUADRANT AND 25 TO 30 KNOT
WINDS OVER THE SOUTHWEST QUADRANT. UPPER-LEVEL ANALYSIS REVEALS A
FAVORABLE ENVIRONMENT WITH LOW TO MODERATE VERTICAL WIND SHEAR AND
STRONGLY DIVERGENT OUTFLOW, ENHANCED BY STRONG SUBTROPICAL
WESTERLIES. 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.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 241700Z.//
NNNN

[bjb]

Looks like there might be some activity in Solomon Islands and Vanuatu over the next few days.
Vanuatu Met Services are watching the low in the Solomons at present.

"Tropical Cyclone Outlook for Vanuatu's Area (12S to 23S and 160E to 175E)

Tropical Cyclone five-day outlook for Vanuatu Area (12.0S160E 23.0S160E 12.0S175.0E to 23.0S175.0E) issued by the Vanuatu Meteorology and Geo-Hazards Department, Port Vila at 6:00 am Wednesday, January 07, 2015

Existing Cyclones in the Vanuatu Area
Nil

Potential Cyclone
There are currently no Tropical Cyclone or Tropical Low within Vanuatu’s Area. However, a low pressure area is currently over the Solomon Islands and expected to move southeast closer to the Northwest of Vanuatu by Wednesday."

[Nev]

Yes, JTWC also keeping an eye on it…

ABPW10 PGTW 060600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/060600Z-070600ZJAN2015//
RMKS/
...
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION HAS PERSISTED NEAR 6.1S 155.1E,
APPROXIMATELY 515 NM EAST-NORTHEAST OF PORT MORESBY, PAPUA NEW
GUINEA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A BROAD,
BUT CONSOLIDATING LOW LEVEL CIRCULATION CENTER WITH FORMATIVE,
ALBEIT BROKEN, CONVECTIVE BANDING THAT IS BEGINNING TO DEVELOP.
UPPER LEVEL ANALYSIS REVEALS AN OVERALL FAVORABLE ENVIRONMENT WITH
MODERATE (05 TO 15 KNOTS) VERTICAL WIND SHEAR AND GOOD OUTFLOW. SEA
SURFACE TEMPERATURES IN THE AREA ARE FAVORABLE FOR DEVELOPMENT.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. NUMERIC
MODEL GUIDANCE IS AGGRESSIVELY DEVELOPING THIS SYSTEM IN THE NEXT 48
TO 72 HOURS. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.
...

[Nev]

This low near the Solomon's is still hanging in there, with another developing on its heels near PNG.
BoM currently have a good risk of TC development this weekend...

Australian Government Bureau of Meteorology
Queensland

Tropical Cyclone Three Day Outlook for the Coral Sea
Issued at 2:46 pm EST on Thursday 8 January 2015
for the period until midnight EST Sunday 11 January 2015.
...
Potential Cyclones:

A monsoon trough currently lies over the far northern Coral Sea, with a weak
low embedded in the trough south of Papua New Guinea and another near the
Solomon Islands. The monsoon trough is expected to develop further as it drifts
south into the Coral Sea into the weekend. There is an increasing risk of
tropical cyclone development over the weekend and into early next week. The
lows are expected to remain offshore of the Queensland coast in the short term
but the situation will continue be monitored carefully.

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

[Manukau heads obs]

models are indicating a low that was formely a tropical low from NW australia will be in the NZ area at the same time as this one from the north...

[Nev]

BoM now not quite as optimistic of TC development by Sunday or Monday.
Conditions still favourable though, so something to keep an eye on over the next few days…

Australian Government Bureau of Meteorology
Queensland

Tropical Cyclone Three Day Outlook for the Coral Sea
Issued at 2:34 pm EST on Friday 9 January 2015
for the period until midnight EST Monday 12 January 2015.
…
Potential Cyclones:

A monsoon trough currently lies over the far northern Coral Sea, with a weak
low embedded in the trough south of Papua New Guinea and another near the
Solomon Islands. There remains an increasing risk of tropical cyclone
development into early next week. The lows are expected to remain offshore of
the Queensland coast in the short term but the situation will continue be
monitored carefully.

Likelihood of a tropical cyclone in the Eastern Region on:
Saturday: Low
Sunday: Moderate
Monday: Moderate

[bjb]

All the conditions are right for the Solomon Islands low to develop.
High SST, High humidity and low wind shear.
Fiji Met Service still have not even listed the low (as it has not passed the magical 160E).

Barry

[Nev]

Hi Barry, Yes, JTWC have just upgraded the Solomon low's chances of forming a TC in the next 24 hrs to medium. They've also acknowledged the PNG low with a current low risk…

ABPW10 PGTW 092200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS REISSUED/092200Z-100600ZJAN2015//
RMKS/
…
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:

(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.5S
155.8E IS NOW LOCATED NEAR 11.0S 159.1E, APPROXIMATELY 110 NM SOUTH-
SOUTHWEST OF HONIARA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
SHOWS AN IMPROVING LOW LEVEL CIRCULATION CENTER (LLCC). A 091757Z
SSMIS IMAGE DEPICTS FORMATIVE BANDING WRAPPING INTO THE LLCC WITH
DEEP CONVECTION ALONG THE NORTHERN AND WESTERN PERIPHERIES. UPPER
LEVEL ANALYSIS INDICATES THAT THE SYSTEM IS CURRENTLY LOCATED IN A
MARGINAL ENVIRONMENT WITH MODERATE (20 KNOTS) VERTICAL WIND SHEAR
(VWS). THE UPPER LEVEL TROUGH CURRENTLY IMPEDING DEVELOPMENT IS
FORECAST TO WEAKEN AND SHIFT EASTWARD REDUCING VWS AND IMPROVING THE
OVERALL UPPER LEVEL ENVIRONMENT. THE SYSTEM IS CURRENTLY IN A
COMPETING STEERING ENVIRONMENT WITH A NEAR EQUATORIAL RIDGE TO THE
NORTH AND A SUB-TROPICAL RIDGE EXTENSION TO THE SOUTH. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 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 UPGRADED TO MEDIUM.

(2) AN AREA OF CONVECTION HAS PERSISTED NEAR 14.6S 148.7E,
APPROXIMATELY 126 NM NORTHWEST OF WILLIS ISLAND. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY SHOWS AN EXPOSED LOW LEVEL CIRCULATION
CENTER (LLCC) WITH AN AREA OF DEEP LINEAR CONVECTION DISPLACED WELL
TO THE NORTHWEST. A 091615Z METOP-B IMAGE DEPICTS WEAK BANDING
WRAPPING INTO A BROAD LLCC WITH LIMITED CONVECTION. WILLIS ISLAND
OBSERVATIONS CONTINUE TO SHOW PERSISTENT 20 TO 25 KT EAST-
SOUTHEASTERLY GRADIENT WINDS ENHANCED BY THE STRONG SUB-TROPICAL
RIDGE (STR) TO THE SOUTH. UPPER LEVEL ANALYSIS INDICATES THAT THE
SYSTEM IS CURRENTLY LOCATED IN AN UNFAVORABLE ENVIRONMENT WITH 30 TO
40 KTS OF VERTICAL WIND SHEAR. THE SYSTEM IS CURRENTLY TRACKING
ALONG THE NORTHERN PERIPHERY OF THE STR LOCATED OVER AUSTRALIA.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 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 LOW.
(3) NO OTHER SUSPECT AREAS.

3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARAGRAPH 2.B.(1) TO
MEDIUM AND ADDED LOW AREA IN PARAGRAPH 2.B.(2).//
NNNN

[Nev]

BoM now back to a high risk of our Solomon's low becoming a TC tomorrow…

Australian Government Bureau of Meteorology
Queensland

Tropical Cyclone Three Day Outlook for the Coral Sea
Issued at 2:30 pm EST on Saturday 10 January 2015
for the period until midnight EST Tuesday 13 January 2015.
…
Potential Cyclones:

A monsoon trough currently lies over the northern Coral Sea with two lows
embedded in it. A low near the Solomon islands lies in a favourable environment
for development and is expected to intensify during the weekend, possibly to
tropical cyclone strength, before moving to the southeast early next week and
remaining well away from Queensland. A second low lies northeast of Queensland
and is expected to remain offshore and in an unfavourable environment during
the weekend. There remains the risk that this low may develop further and move
towards the Queensland Coast during next week.

Likelihood of the low near the Solomon Islands becoming a tropical cyclone in
the Eastern Region on:
Sunday: High
Monday: Moderate
Tuesday: Low

Likelihood of a tropical cyclone in the northwest Coral Sea on:
Sunday: Low
Monday: Moderate
Tuesday: Moderate

Edit: Updated sat-pic

[Nev]

BoM issued its first advisories for the Solomon's Low last night and expect TC genesis by this morning, then reaching Cat 2 by tomorrow morning…

Australian Government Bureau of Meteorology
Queensland Region
Tropical Cyclone Warning Centre

TROPICAL CYCLONE INFORMATION BULLETIN
For 9:08 pm EST on Saturday 10 January 2015
At 8 pm EST Saturday, a Tropical Low with central pressure 999 hPa was located
over the Solomon Sea near latitude 11.5 south longitude 159.4 east, which is
about 160 km northwest of Indispensable Reef and 240 km south southwest of
Honiara.

The low is moving south southeast at about 6 kilometres per hour and should
intensify over the next 24 hours.

This system is not expected to move towards Queensland.

Another system in the northwest Coral Sea is also being monitored, and advice
will be provided for that if necessary.

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by BRISBANE TROPICAL CYCLONE WARNING CENTRE
at: 1247 UTC 10/01/2015
Name: Tropical Low
…
REMARKS:
During the afternoon period the deep convection was rather limited in extent,
but was nonetheless within about 20nm of the low level centre evident on the
visible imagery. Held the T to 2.5 during the afternoon using the Dvorak 1995
discression for shear patterns based on limited convection strength and extent.
The latest image shows more substantial convection now near the probable centre,
in line with our overnight intensification forecast, however it's only the first
image, so we'll hold at 2.5 yet reiterate the policy is for possible TC genesis
within 6 hours. Two channel outflow to NW and SE as the system lies flanked by
an upper trough to the south and monsoon return flow to the north. Very high
SST [-30C]. Shear moderate and forecast to remain that way for 24-36 hours,
then increasing as the system perhaps gets more of a baroclinic structure.

[Nev]

The Solomon's low making progress, but still taking its time…

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by BRISBANE TROPICAL CYCLONE WARNING CENTRE
at: 0049 UTC 11/01/2015
Name: Tropical Low
Identifier: 07U
Data At: 0000 UTC
Latitude: 12.7S
Longitude: 159.2E
Location Accuracy: within 20 nm [35 km]
Movement Towards: south southwest [192 deg]
Speed of Movement: 6 knots [11 km/h]
Maximum 10-Minute Wind: 30 knots [55 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 998 hPa
...
REMARKS:
Overnight the deep convection has continued, with the cloud still separated from
the low level centre. Shear pattern used for Dvorak, less than 0.75 deg from
LLC. Location good with GMI Microwave Image at 22:36Z. TC genesis still possible
through the next 12 to 24 hours. Two channel outflow to NW and SE as the system
lies flanked by an upper trough to the south and monsoon return flow to the
north. Very high SST [30C]. Shear generally moderate, though forecast to
increase in the next 48 hours, which will then lead to more of a baroclinic
structure.

[bjb]

Nev

Yes, it is taking a while.
Vanuatu Met Service are tracking as well.
But they are suggesting it will hold as Cat. 2 for longer than BOM suggest.

Barry

[Nev]

Yes, I suspect Vanuatu Met may be playing catch-up. Their latest track-map is very similar to BoM's earlier track-maps…

Information Number 1 on a Tropical Low issued by the Vanuatu Meteorology
and Geo-Hazards Department, Port Vila at 12:02pm VUT Sunday 11 January 2015.

At 11:00am local time today, a tropical low (997 hPa) was located near
12.1S 159.9E. This is about 740 KM west of Torres and still out of the
Vanuatu Area of Responsibility and the Vanuatu Tropical Cyclone Tracking
Map. The system is moving south southeast at 7 KM/HR. The potential for
the tropical low to become a tropical cyclone within the next 48 hours
and move towards the Vanuatu group is moderate.
…
The system is not a threat to any island of Vanuatu at this time.
However, heavy rainfall and flooding is expected throughout Vanuatu
in the next 12 to 24 hours.

[Nev]

Starting to look a little less likely now. Good convection and SST's but too much shear aloft...

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by BRISBANE TROPICAL CYCLONE WARNING CENTRE
at: 0716 UTC 11/01/2015
Name: Tropical Low
Identifier: 07U
Data At: 0600 UTC
Latitude: 13.4S
Longitude: 158.3E
Location Accuracy: within 40 nm [75 km]
Movement Towards: south southwest [214 deg]
Speed of Movement: 9 knots [16 km/h]
Maximum 10-Minute Wind: 30 knots [55 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 998 hPa
…
REMARKS:
Deep convection continues to be displaced to the north of the low level
circulation centre evident in vis imagery, consistent with southerly vertical
shear near 20 knots over the system as estimated from AMSU. Dvorak based on
curved band averaging 0.3 wrap, yielding DT of 2.0. Shear pattern yields DT of
3.0, although less confidence is given to this pattern at this point in the
system's life cycle. MET is 3.0, PAT is 2.5. FT set at 2.5 based mainly on PAT.

The system is located in an environment characterised by moderate southerly
vertical wind shear, which is forecast to only slightly weaken in the next 24
hours, before gradually increasing once more. Dual outflow channel structure
aloft remains in place. SSTs are 29 to 30C over the forecast track. Slight
intensification to reach weak TC strength remains a moderate possibility through
the next 12 to 24 hours in this neutral to marginally favourable environment,
however if the system reaches this threshold it is unlikely to sustain it for
long given the increasingly hostile environment beyond 24 hours.

Some weak interaction with the tropical low [06U] to the west may be influencing
the track at present, leading to a recent SSW or even SW motion. This
interaction should end in the next 12 to 24 hours, with the upper level trough
to the south becoming the dominant steering feature. This in turn should lead to
a change to a SE and eventually ESE track from the latter half of Monday, with
increasing forward speed.

[Nev]

Chances of either low becoming a TC now look doubtful. BoM issued their last TC advisories this morn…

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by BRISBANE TROPICAL CYCLONE WARNING CENTRE
at: 1920 UTC 11/01/2015
Name: Tropical Low
Identifier: 07U
Data At: 1800 UTC
Latitude: 14.4S
Longitude: 155.9E
Location Accuracy: within 45 nm [85 km]
Movement Towards: south [184 deg]
Speed of Movement: 3 knots [6 km/h]
Maximum 10-Minute Wind: 25 knots [45 km/h]
Maximum 3-Second Wind Gust: 40 knots [75 km/h]
Central Pressure: 999 hPa
...
REMARKS:
Despite a transitory puff of convection near the LLCC during the last few hours,
the main deep convection associated with this system continues to be displaced
to the north of the low level circulation centre. This is consistent with
southerly vertical shear near 20 knots over the system as estimated from AMSU.
Dvorak based on a shear pattern with DT of 1.5. MET is 2.0 and PAT is 1.5. Final
T 1.5 with CI 2.0.

The system is located in an environment characterised by moderate southerly
vertical wind shear, which is forecast to only slightly weaken in the next 24
hours, before gradually increasing once more. Intensification to weak TC
strength is no longer considered likely, with little dynamic or statistical
guidance forecasting this and a brief window of opportunity in a marginal
environment at best.

Some interaction with the tropical low [06U] to the west likely influenced the
track yesterday, leading to a rather rapid SW to WSW motion. This motion appears
to have ended during the last 6 hours based on microwave fixes. The upper level
trough to the south should become the dominant steering feature today, leading
to a change to a SE and eventually ESE track with increasing forward speed.

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

[Nev]

As mentioned in the NZ Weather thread, there are currently 2 areas of interest for potential cyclogenesis.

The one just south of the Solomon's has been progged by Australia's Access-G model for TC development for the last few days, with other models now seeming to come in line, and JTWC issuing its first Tropical Disturbance Summary last night with a low risk of becoming a TC in the next 24 hours. RSMC Nadi also issued a Tropical Disturbance Advisory last night as it crossed to its AoR, with moderate to high risk in the next 24 to 48 hours…

ABPW10 PGTW 290600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/290600Z-300600ZJAN2015//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION HAS PERSISTED NEAR 17.8S 159.0E,
APPROXIMATELY 516 NM WEST-NORTHWEST OF NOUMEA, NEW CALEDONIA.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS FLARING DEEP
CONVECTION BROADLY WRAPPING INTO AN ILL-DEFINED LOW-LEVEL
CIRCULATION CENTER. A 290300Z NOAA-19 MICROWAVE IMAGE REVEALS WEAK
AND FRAGMENTED CONVECTIVE BANDING OVER THE NORTHERN PERIPHERY
WRAPPING TOWARDS THE CENTER. AN OLDER 282228Z ASCAT PASS SHOWED A
WELL-DEFINED, BUT WEAK (10 TO 15 KNOT) CIRCULATION WITH 20 TO 25
KNOT WIND BARBS ALONG THE NORTHERN PERIPHERY. UPPER-LEVEL ANALYSIS
INDICATES THE DISTURBANCE IS LOCATED AN AREA OF FAVORABLE
ENVIRONMENT WITH LOW TO MODERATE (10 TO 20 KNOT) VERTICAL WIND SHEAR
WITH GOOD POLEWARD OUTFLOW. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 15 TO 20 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 LOW.
(2) NO OTHER SUSPECT AREAS.//
NNNN

TROPICAL DISTURBANCE ADVISORY NUMBER A1 ISSUED FROM RSMC NADI
Jan 29/1355 UTC 2015 UTC.

TROPICAL DEPRESSION 09F CENTRE 1000HPA WAS LOCATED NEAR 17.5S 160.0E
AT 291200 UTC. POSITION POOR BASED ON HR GMS EIR IMAGERY AND
PERIPHERAL SURFACE REPORTS. DEPRESSION MOVING EAST NORTHEAST AT ABOUT
10 KNOTS. MAXIMUM 10-MINUTE AVERAGE WINDS NEAR THE CENTRE ESTIMATED
AT ABOUT 20 KNOTS.

DEEP CONVECTION HAS INCREASED AND OVERALL ORGANINSATION HAS IMPROVED
PAST 24 HOURS.
SYSTEM LIES UNDER AN UPPER RIDGE IN A LOW SHEARED ENVIRONMENT.
CYCLONIC CIRCULATION EXTEND TO 700HPA. SST AROUND 30 DEGREES CELSIUS.

GOBAL MODELS HAVE PICKED THE SYSTEM AND MOVE IT EAST-NORTHEAST WITH
FURTHER INTENSIFICATION.

POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN THE
NEXT 24 TO 48 HOURS IS MODERATE TO HIGH.
...

RSMC Nadi has also been issuing Tropical Disturbance Summaries for the other one north of FIji for the last few days, with a current low to moderate risk of it becoming a TC in the next 24 to 48 hours (down from a moderate to high risk earlier yesterday).…

Tropical Disturbance Summary For area Equator to 25S, 160E to 120W
ISSUED FROM RSMC NADI Jan 29/0825 UTC 2015 UTC.

TROPICAL DISTRURBANCE 08F [1003HPA] ANALYSED NEAR 14.2S 176.4W AT
290600UTC. SLOW MOVING. POSITION POOR BASED ON GOES IR IMAGERY AND
PERIPHERAL SURFACE REPORTS. SST AROUND 30 DEGREES CELCIUS.

CONVECTION REMAINS PERSISTENT IN THE LAST 24 HOURS BUT DISPLACED TO
THE NORTH. ORGANISATION HAS IMPROVED SLIGHTLY IN THE PAST 12 HOURS.
SYSTEM LIES JUST SOUTH OF AN UPPER LEVEL RIDGE IN A LOW SHEARED
ENVIRONMENT. CYCLONINC CIRCULATION EXTENDS UPTO 850HPA.

GLOBAL MODELS HAVE PICKED UP THE SYSTEM AND MOVE IT SOUTHEAST WITH
SLIGHT INTENSIFICATION.

POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN THE
NEXT 24 TO 48 HOURS IS LOW TO MODERATE.

NO OTHER SIGNIFICANT TROPICAL DISTURBANCE ANALYSED OR FORECAST IN THE
AREA.

Edit: updated.