Tropical Cyclones Winston & Tatiana

[jamie]

I see GFS is toying with the idea of a decent cyclone to the north of us. Something to keep an eye on.

[Nev]

Yes, there's actually 2 areas of interest for potential development atm, that one north of Fiji and another just below the Solomon's…

[Nev]

RSMC Nadi issued a Disturbance Summary not long ago for the low NW of Fiji. Although still fairly disorganised, convection skirting the LLCC has been flaring fairly intensely this morn.

(Meanwhile, the low south of the Solomon's is struggling.)

Tropical Disturbance Summary For area Equator to 25S, 160E to 120W
ISSUED FROM RSMC NADI Feb 072320 UTC.

TROPICAL DISTURBANCE 09F [1005HPA] ANALYSED NEAR 8.4S 170.6E AT
072100UTC SLOW MOVING. POSITION BASED ON IR IMAGERY WITH ANIMATION
AND PERIPHERAL OBSERVATIONS. SST AROUND AROUND 30 DEGREES CELCIUS.

CONVECTION REMAINS PERSISTENT, HOWEVER, ORGANIZATION IS POOR.
CONVECTION IS DISPLACED TO THE NORTHWEST OF THE SUPPOSED LLCC.
CYCLONIC CIRCULATION EXTENDS FROM THE SURFACE UP TO 500HPA. TD09F
LIES IN A LOW SHEARED ENVIRONMENT. OUTFLOW GOOD TO THE NORTHWEST AND
SOUTH BUT RESTRICTED ELSEWHERE.

MOST GLOBAL MODELS HAVE PICKED UP THE SYSTEM AND ARE MOVING IT
SOUTHEAST WITH GRADUAL INTENSIFICATION.

POTENTIAL FOR TD09F TO DEVELOP INTO A TROPICAL CYCLONE IN THE NEXT 24
TO 48 HOURS IS LOW.

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

[Nev]

JTWC issued their first advisory on these 2 potential systems earlier this morning. And last night the chances of low now north of Vanuatu (TD 09F/98P) becoming a TC in the next 24-48 hours was upgraded to low-to-moderate by RSMC Nadi.

Tropical Disturbance Summary For area Equator to 25S, 160E to 120W
ISSUED FROM RSMC NADI Feb 080931 UTC.

TROPICAL DISTURBANCE 09F [1003HPA] ANALYSED NEAR 9.1S 169.5E AT
080600UTC SLOW MOVING. POSITION BASED ON IR IMAGERY WITH ANIMATION
AND PERIPHERAL OBSERVATIONS. SST AROUND AROUND 30 DEGREES CELCIUS.

CONVECTION REMAINS PERSISTENT. ORGANIZATION POOR. CYCLONIC
CIRCULATION EXTENDS UPTO 700HPA. SYSTEM LIES IN A LOW SHEARED
ENVIRONMENT UNDER MODERATE UPPER DIVERGENCE REGION.

MOST GLOBAL MODELS HAVE PICKED UP THE SYSTEM AND ARE MOVING IT SOUTH
WITH GRADUAL INTENSIFICATION.

POTENTIAL FOR TD09F TO DEVELOP INTO A TROPICAL CYCLONE IN THE NEXT 24
TO 48 HOURS IS LOW TO MODERATE.

ABPW10 PGTW 081400
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS REISSUED/081400Z-090600ZFEB2016//
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 (INVEST 97P) HAS PERSISTED NEAR
16.2S 156.9E, APPROXIMATELY 650 NM WEST-NORTHWEST OF NOUMEA, NEW
CALEDONIA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A
COMPACT WEAK LOW LEVEL CIRCULATION CENTER (LLCC) WITH FLARING
CONVECTION CONSOLIDATING ON THE WESTERN PERIPHERY OF THE LLCC. UPPER
LEVEL CONDITIONS ARE MARGINAL WITH MODERATE (15 TO 20 KNOTS)
VERTICAL WIND SHEAR (VWS) OFFSET BY DUAL OUTFLOW CHANNELS. GLOBAL
MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE DEVELOPMENT OF THIS
SYSTEM. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS LOW.

(2) AN AREA OF CONVECTION (INVEST 98P) HAS PERSISTED NEAR 9.4S
167.9E, APPROXIMATELY 470 NM EAST OF HONIARA, SOLOMON ISLANDS.
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A BROAD LOW
LEVEL CIRCULATION CENTER (LLCC) WITH DEEP FLARING CONVECTION
CONSOLIDATING INTO BANDS CONVERGING TOWARDS THE LLCC. A 081001Z
ASCAT PASS CONFIRMS THE LLCC HAS CONSOLIDATED FROM AN AREA OF
TROUGHING OVER THE PAST 12 HOURS, WITH A LARGE SWATH OF 15-20 KNOT
WINDS ON THE NORTHERN SIDE OF THE LLCC. THE UPPER LEVEL ENVIRONMENT
IS MARGINAL WITH MODERATE (15 TO 20 KNOTS) VERTICAL WIND SHEAR (VWS)
BEING OFFSET BY GOOD RADIAL OUTFLOW. GLOBAL MODELS ARE IN GOOD
AGREEMENT ON THE DEVELOPMENT OF THIS SYSTEM. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS LOW.

[Nev]

The Coral Sea low SW of the Solomon's looks to have become a lot more organised with deep convection today and JTWC has upgraded its chances of becoming a TC in the next 24-48 hrs to medium. The BoM (and MetService) still gave it a low chance earlier today.

Meanwhile the low north of Vanuatu looks less organised today. JTWC still only rate its chances of becoming a TC in the next 24-48 hrs at low, while RSMC Nadi (and MetService) rate its chances at medium.

ABPW10 PGTW 090600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS 090600Z-100600ZFEB2016//
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
16.2S 156.9E IS NOW LOCATED NEAR 16.3S 155.0E, APPROXIMATELY 723 NM
WEST-NORTHWEST OF NOUMEA, NEW CALEDONIA. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS A SLOWLY CONSOLIDATING LOW-LEVEL
CIRCULATION CENTER WITH PERSISTENT DEEP CONVECTION WRAPPING INTO THE
SYSTEM. A 090439Z SSMI 37 GHZ IMAGE REVEALS CURVED CONVECTIVE
BANDING ALONG THE NORTHERN AND SOUTHERN PERIPHERIES. RECENT
SCATTEROMETRY DATA SHOW A DEFINED CENTER, IN GOOD AGREEMENT WITH THE
ANALYZED POSITION, WITH 15 TO 20 KNOTS ALONG THE NORTHERN PERIPHERY
AND 20 TO 25 KNOTS TO THE SOUTHWEST. UPPER LEVEL ANALYSIS INDICATES
A FAVORABLE ENVIRONMENT WITH LIGHT-MODERATE (15 TO 20 KNOTS)
VERTICAL WIND SHEAR AND GOOD DUAL CHANNEL OUTFLOW. GLOBAL MODELS ARE
IN GOOD AGREEMENT ON THE DEVELOPMENT OF THIS SYSTEM OVER THE NEXT 24
TO 48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO
25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1001
MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM.

(2) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.4S 167.9E
IS NOW LOCATED NEAR 11.8S 168.2E, APPROXIMATELY 470 NM EAST-
SOUTHEAST OF HONIARA, SOLOMON ISLANDS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS A BROAD LOW-LEVEL CIRCULATION CENTER
(LLCC) WITH FLARING DEEP CONVECTION WRAPPING INTO THE SYSTEM. A
090437Z SSMIS 91 GHZ IMAGE REVEALS FRAGMENTED CONVECTIVE BANDING
AROUND THE PERIPHERY OF THE LLCC. RECENT SCATTEROMETRY DATA SHOW 10
TO 15 KNOT WINDS ALONG THE SOUTHERN PERIPHERY AND 15 TO 20 KNOT
WINDS TO THE NORTH. UPPER LEVEL ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT WITH LIGHT-MODERATE (10 TO 20 KNOTS) VERTICAL WIND SHEAR
AND GOOD OUTFLOW. GLOBAL MODELS ARE IN FAIR AGREEMENT ON THE GRADUAL
DEVELOPMENT OF THIS SYSTEM. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1002 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.
...

[jamie]

The thing I like about these two systems is they are on a crash course for each other just north of NZ.

[Nev]

Nearby twin TC's tend to initially attract then orbit each, with the dominant one often absorbing the other, known the 'Fujiwhara effect'. Question is, which is now more likely to be the dominant one?

[jamie]

Yea I'm excited by the super large amount of moisture. Yes one will die but some of it's moisture should be transferred should it not?

[David]

Wow, 12Z GFS showing a direct hit on NZ with the low centre moving down Coromandel and into BOP at 975hPa

[jamie]

Wow, 12Z GFS showing a direct hit on NZ with the low centre moving down Coromandel and into BOP at 975hPa

That's some weather forecast maps worth saving! Looks awesome!

[Nev]

JTWC have issued a TC Formation Alert for the Coral Sea low this arvo, while the BoM upgraded it chances to moderate this morning…

WTPS21 PGTW 100130
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 15.8S 154.2E TO 17.3S 158.3E
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 100000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 16.0S 154.5E. THE SYSTEM IS MOVING NORTHWARD AT 01 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR
16.3S 155.0E IS NOW LOCATED NEAR 16.0S 154.5E, APPROXIMATELY 775 NM
WEST-NORTHWEST OF NOUMEA, NEW CALEDONIA. RECENT ANIMATED
MULTISPECTRAL SATELLITE IMAGERY SHOWS PATCHY DEEP CONVECTION
DEVELOPING OVER A CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC)
EVIDENT IN A 092313Z AMSU IMAGE. RECENT SCATTEROMETRY DATA DEPICT
25 TO 30 KNOT WINDS ALONG THE SOUTHERN PERIPHERY OF THE LLCC. UPPER
LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT, WITH LIGHT-
MODERATE (15 TO 20 KNOTS) VERTICAL WIND SHEAR AND A STRONG POLEWARD
OUTFLOW CHANNEL. GLOBAL MODELS PREDICT CONTINUED DEVELOPMENT OF THIS
SYSTEM OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 999 MB. BASED ON THE IMPROVING LOW LEVEL SIGNATURE AND
PERSISTENT UPPER LEVEL SUPPORT, 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
110130Z.//
NNN

BoM - Updated Tropical Cyclone Outlook for Coral Sea
Issued at 5:18 am EST on Wednesday 10 February 2016
for the period until midnight EST Friday 12 February 2016.
Existing Cyclones in the Eastern Region:

Nil.

Potential Cyclones:

A slow moving low pressure system is currently located over the central Coral Sea well offshore of the east Queensland coast. The low is expected to remain slow moving during today and Thursday and should then shift southeastwards from late Thursday. An increasing monsoonal flow to the north of the system will combine with a southeasterly wind surge to the south to result in a deepening of the low over the next few days. Upper atmospheric conditions are now more favourable for further intensification, resulting in a moderate chance of TC development late Thursday or Friday.

The low is expected to remain well offshore and does not pose an immediate threat to the Queensland coast.

Likelihood of a tropical cyclone in the Eastern Region on:
Wednesday:Low
Thursday:Moderate
Friday:Moderate

[Nev]

JTWC have also issued a TC Formation Alert for the low just to the NE of Vanuatu this evening…

WTPS22 PGTW 100500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
140 NM EITHER SIDE OF A LINE FROM 13.7S 169.6E TO 17.5S 172.7E
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 SYNOPTIC DATA AT 100000Z INDICATE THAT A CIRCULATION
CENTER IS LOCATED NEAR 14.1S 170.0E. THE SYSTEM IS MOVING
SOUTHEASTWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 14.1S
170.0E IS NOW LOCATED NEAR 14.1S 170.0E, APPROXIMATELY 480 NM WEST-
NORTHWEST OF NADI, FIJI. RECENT ANIMATED MULTISPECTRAL SATELLITE
IMAGERY REVEALS IMPROVED, DEEP CONVECTIVE BANDING WRAPPING INTO A
WELL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC). A 100216Z GPM 36
GHZ IMAGE ALSO DEPICTS A CONSOLIDATING LLCC WITH GOOD SPIRAL BANDING
WRAPPING IN FROM THE NORTH. RECENT SCATTEROMETRY DATA SHOWS 25 TO 30
KNOT WINDS ALONG THE SOUTHERN PERIPHERY WHICH IS IN LINE WITH LATEST
DVORAK INTENSITY ESTIMATES RANGING FROM T1.5-2.0. UPPER LEVEL
ANALYSIS SHOWS A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH NEAR
RADIAL OUTFLOW AND LOW-MODERATE (10 TO 20 KNOTS) VERTICAL WIND
SHEAR. GLOBAL MODEL GUIDANCE IS IN GOOD AGREEMENT ON THE DEVELOPMENT
OF THE SYSTEM OVER THE NEXT 24 TO 36 HOURS. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. BASED ON THE CONSOLIDATING
LLCC AND FAVORABLE UPPER LEVEL CONDITIONS, 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
110500Z.//

[Nev]

JTWC upgraded the low east of Vanuatu to a TC earlier this morning (based on 1-minute winds).
RSMC Nadi also began issuing TD Advisories last night, and I expect they'll probably name her later this morning or today. Central pressure 998 hPa and max 10-minute winds of about 45 km/h…

WTPS31 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 11P (ELEVEN) WARNING NR 001//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/100451ZFEB16//
AMPN/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. TROPICAL CYCLONE 11P (ELEVEN) WARNING NR 001
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
101200Z --- NEAR 15.3S 170.9E
MOVEMENT PAST SIX HOURS - 150 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
...
REMARKS:
101500Z POSITION NEAR 15.7S 171.1E.
TROPICAL CYCLONE (TC) 11P (ELEVEN), LOCATED APPROXIMATELY 463 NM WEST-
NORTHWEST OF SUVA, FIJI, HAS TRACKED SOUTH-SOUTHEASTWARD AT 09 KNOTS
OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS
A RAPIDLY CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH
IMPROVED CONVECTIVE BANDING. A 101003Z METOP-A 89GHZ IMAGE SHOWS
DEEP CONVECTIVE BANDING WRAPPING INTO A WELL-DEFINED CENTER. OVERALL,
THERE IS GOOD CONFIDENCE IN THE CURRENT POSITION. THE CURRENT INTENSITY
IS ASSESSED AT 35 KNOTS BASED ON A PGTW DVORAK ESTIMATE OF T2.5 (35
KNOTS). TC 11P IS FORECAST TO TRACK POLEWARD ALONG THE WESTERN PERIPHERY
OF THE SUBTROPICAL RIDGE THROUGH TAU 72. AFTER TAU 72, TC 11P SHOULD
ENCOUNTER STRONG SUBTROPICAL WESTERLIES AND WILL WEAKEN SIGNIFICANTLY
WHILE TURNING EASTWARD. TC 11P IS NOT FORECAST TO UNDERGO EXTRA-TROPICAL
TRANSITION AND SHOULD SLOW AFTER TAU 96 AS A STRONG LOW-LEVEL RIDGE BUILDS
TO THE EAST AND SOUTH. DYNAMIC GUIDANCE IS IN GOOD AGREEMENT. TC 11P IS
FORECAST TO RAPIDLY INTENSIFY TO A PEAK INTENSITY OF 105 KNOTS BY TAU 60
DUE TO EXCELLENT POLEWARD OUTFLOW, WARM SST AND LOW VERTICAL WIND SHEAR (VWS).
SIGNIFICANT WEAKENING IS EXPECTED SOUTH OF 25S DUE TO COOLER SST AND STRONG
VWS. THIS WARNING SUPERSEDES AND CANCELS REF A, JOINT TYPHOON WRNCEN PEARL
HARBOR HI 100500Z FEB 16 TROPICAL CYCLONE FORMATION ALERT (WTPS22 PGTW 100500).//
NNNN

TROPICAL DISTURBANCE ADVISORY NUMBER A2 ISSUED FROM RSMC NADI
Feb 101338 UTC.

TROPICAL DEPRESSION 09F CENTRE 998HPA WAS LOCATED NEAR 15.2S 170.8E
AT 101200 UTC. POSITION POOR BASED ON HR MTSAT IR IMAGERY AND SURFACE
OBSERVATIONS. TD09F MOVING SOUTHEAST-SOUTHEAST AT ABOUT 07 KTS.
MAXIMUM 10 MINUTE AVERAGE WINDS NEAR THE CENTRE ESTIMATED AT ABOUT 25
KNOTS.

DEEP CONVECTION HAS INCREASED WITH BANDS TRYING TO WRAP AROUND LLCC.
ORGANIZATION HAS IMPROVED IN THE PAST 24 HOURS. CYCLONIC CIRCULATION
EXTENDS TO 400HPA. SST AROUND 31 DEGREES CELSIUS. SYSTEM LIES UNDER
AN UPPER HIGH IN A LOW SHEARED ENVIRONMENT. OUTFLOW GOOD. SYSTEM IS
BEING STEERED TO THE SOUTH-SOUTHEAST BY THE SUBTROPICAL RIDGE LOCATED
TO THE SOUTHEAST. DVORAK ANALYSIS BASED ON 0.35 WRAP YIELDS DT=2.0.
MET AND PT AGREE. THUS, YEILDING T2.0/2.0/D1.0/24HRS.

GLOBAL MODELS MOVE THE SYSTEM SOUTH-SOUTHEASTWARDS WITH FURTHER
INTENSIFICATION.

POTENTIAL FOR TD09F TO DEVELOP INTO A TROPICAL CYCLONE IN THE NEXT 12
TO 18 HOURS IS TO HIGH.
...

[Manukau heads obs]

if the remains can get far enough south and arrive in the NZ area at the same time as the next tasman low/southerly change, then the idea of the models have of that resulting in a large low pressure system developing right over NZ is an interesting one and one to watch

[Nev]

Not surprisingly, the BoM earlier this morning upgraded the Coral Sea low's chance of becoming a TC today as moderate and tomorrow as high. Be interesting to see you gets to name it.

BoM - Updated Tropical Cyclone Outlook for Coral Sea
Issued at 3:33 am EST on Thursday 11 February 2016
for the period until midnight EST Saturday 13 February 2016.
…
Potential Cyclones:

A tropical low situated over the central Coral Sea is gradually intensifying while moving in a general eastwards direction. The low is expected to continue moving in this direction over the next couple of days and is rated a high chance of forming into tropical cyclone before exiting the region on Friday.

The low is expected to remain well offshore and does not pose a threat to the Queensland coast.


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

BPW10 PGTW 101600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS REISSUED/101600Z-110600ZFEB2016//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/101352ZFEB2016//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/100121ZFEB2016//
NARR/REF A IS A TROPICAL CYCLONE WARNING. REF B IS A TROPICAL
/CYCLONE FORMATION ALERT.//
RMKS/
…
B. TROPICAL DISTURBANCE SUMMARY:
...
(2) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 16.3S
155.0E IS NOW LOCATED NEAR 16.0S 154.5E, APPROXIMATELY 775 NM
WEST-NORTHWEST OF NOUMEA, NEW CALEDONIA. RECENT ANIMATED
MULTISPECTRAL SATELLITE IMAGERY SHOWS PATCHY DEEP CONVECTION
DEVELOPING OVER A CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC)
EVIDENT IN A 092313Z AMSU IMAGE. RECENT SCATTEROMETRY DATA DEPICT
25 TO 30 KNOT WINDS ALONG THE SOUTHERN PERIPHERY OF THE LLCC. UPPER
LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT, WITH LIGHT-
MODERATE (15 TO 20 KNOTS) VERTICAL WIND SHEAR AND A STRONG POLEWARD
OUTFLOW CHANNEL. GLOBAL MODELS PREDICT CONTINUED DEVELOPMENT OF
THIS SYSTEM OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS
ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 999 MB. SEE REF B (WTPS21 PGTW 100130) FOR
FURTHER DETAILS. BASED ON THE IMPROVING LOW LEVEL SIGNATURE AND
PERSISTENT UPPER LEVEL SUPPORT, THE POTENTIAL FOR THE DEVELOPMENT
OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS
HIGH.
...

[Nev]

JTWC now referring to the Coral Sea low as TC (based on 1-minute winds)…

WTPS32 PGTW 102100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 12P (TWELVE) WARNING NR 001//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/100121Z FEB 16//
AMPN/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. TROPICAL CYCLONE 12P (TWELVE) WARNING NR 001
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
101800Z --- NEAR 16.7S 156.3E
MOVEMENT PAST SIX HOURS - 145 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
…
REMARKS:
102100Z POSITION NEAR 16.8S 156.5E.
TROPICAL CYCLONE 12P (TWELVE), LOCATED APPROXIMATELY 603 NM EAST
OF CAIRNS, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT 06 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFARED SATTELITE IMAGERY
DEPICTS AN AREA OF STRONG CONVECTION WRAPPING TIGHTLY INTO A LOW
LEVEL CIRCULATION CENTER (LLCC) AND CONFIRMED BY A 101716Z SSMIS 91
GHZ MICROWAVE IMAGE. A 101144Z METOP-A ASCAT IMAGE DEPICTS THE LLCC
WITH 35 KNOT WINDS ON THE WESTERN PERIPHERY SUPPORTING THE INITIAL
INTENSITY AND POSITION WITH HIGH CONFIDENCE. UPPER-LEVEL ANALYSIS
INDICATES THE PRESENCE OF A STRONG POLEWARD OUTFLOW CHANNEL BEING
OFFSET BY MODERATE (20 TO 25 KNOTS) OF VERTICAL WIND SHEAR (VWS).
THE PRIMARY STEERING MECHANISM IS AN INDUCED NORTH-SOUTH ORIENTED
RIDGE POSITIONED BETWEEN TC 11P AND TC 12P WHICH WILL GUIDE 12P
SOUTH. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT FOR THE FIRST 36
HOURS GIVING HIGH CONFIDENCE TO THE NEAR-TERM FORECAST TRACK. AFTER
36 HOURS, MODEL GUIDANCE UNCERTAINTY INCREASES AS THE RIDGE BETWEEN
TC 11P AND TC 12P IS EXPECTED TO BREAK DOWN AND INTERACTION
WITH TC 12P IS POSSIBLE GIVING LOW CONFIDENCE TO THE LONG-TERM
FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 101800Z IS 12
FEET. NEXT WARNINGS AT 110900Z AND 112100Z. REFER TO TROPICAL
CYCLONE 11P (ELEVEN) WARNINGS (WTPS31 PGTW) FOR TWELVE-HOURLY
UPDATES. THIS SUPERSEDES AND CANCELS REF A (WTPS21 PGTW 100130).

[Nev]

TC Winston east of Vanuatu was named by RSMC Nadi this afternoon.

GALE WARNING 002 ISSUED FROM RSMC NADI Feb 110143 UTC.

TROPICAL CYCLONE WINSTON CENTRE 995HPA CATEGORY 1 WAS LOCATED NEAR
15.7 SOUTH 171.2 EAST AT 110000 UTC.
POSITION FAIR.
REPEAT POSITION 15.7S 171.22E AT 110000 UTC.
CYCLONE MOVING SOUTHEAST AT 05 KNOTS. CYCLONE INTENSIFYING.
EXPECT SUSTAINED WINDS OF 35 KNOTS CLOSE TO THE CENTRE INCREASING TO
45 KNOTS BY 120000 UTC.
...

Thought I'd split these 2 systems into a separate thread. Although the Coral Sea low is yet to be named, they're so closely interlinked, that it seems make more sense to keep them together in the same thread.

[Nev]

The BoM also began issuing Advisories for the Coral Sea low this afternoon…

Australian Government Bureau of Meteorology
Queensland Region
Tropical Cyclone Warning Centre

TROPICAL CYCLONE INFORMATION BULLETIN
For 11:01 am EST on Thursday 11 February 2016
At 10 am AEST Thursday, a Tropical Low with central pressure 999 hPa was
located over the central Coral Sea near latitude 16.5 south longitude 157.2
east, which is about 990 km east northeast of Mackay and 1220 km east of Cairns.

The low is moving east at about 10 kilometres per hour, and a curve onto a
southeasterly track is expected through the remainder of today into Friday.
This is likely to take the system out of the Queensland region late on Friday
or Saturday morning.

It is considered quite likely that the system will continue to slowly develop
and it may become a tropical cyclone overnight tonight or Friday morning.

The system is located well offshore and expected to move further away; it does
not pose a threat to the Queensland coast.

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by BRISBANE TROPICAL CYCLONE WARNING CENTRE
at: 0146 UTC 11/02/2016
Name: Tropical Low
Identifier: 10U
Data At: 0000 UTC
Latitude: 16.5S
Longitude: 157.2E
Location Accuracy: within 45 nm [85 km]
Movement Towards: east [098 deg]
Speed of Movement: 5 knots [10 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
…
REMARKS:
Location fix based primarily on animated visible imagery. The system has been
gaining in organisation, particularly in the past 12 hours, with curvature in
deep convection gradually improving. On the other hand, the deep convection
remains confined to the southwestern semi-circle, consistent with moderate N/NE
vertical wind shear over the system, consistent with CIMSS shear product. Dvorak
analysis based on shear pattern, with edge of deep convection over the low level
centre yields a DT of 3.0. Caution with using the shear pattern in development
stages suggests bias towards the PT of 2.5, hence the FT set at 2.5.

Recent motion has been to the East at about 5 knots, primarily under the
influence of low level monsoon flow to the north, and a mid level shortwave
trough to the south. The system is expected to curve to the southeast in the
next 12 to 24 hours, as the shortwave trough to the south lifts out to the
southeast, a second shortwave trough develops over eastern Queensland, and some
indirect interaction with 11P east of Vanuatu develops, manifest as shortwave
low to mid level ridging developing between the two systems.

The system remains in an environment marginally supportive of further
development, ample ocean heat content, and moderate northerly vertical wind
shear persisting for the next 24 hours or so. This should lead to at least
modest further strengthening overnight into Friday. Following this, vertical
shear is forecast to increase over the system as the second stronger shortwave
trough over eastern Queensland spreads its influence over the system, which
should lead to a weakening or at least a loss of tropical characteristics during
Saturday.
…

[Nev]

Latest RSMC Nadi Advisory for TC Winston…

TROPICAL DISTURBANCE ADVISORY NUMBER A4 ISSUED FROM RSMC NADI
Feb 110201 UTC.

TROPICAL CYCLONE WINSTON CENTRE 995HPA WAS LOCATED NEAR 15.7S 171.2E
AT 110000 UTC. POSITION FAIR BASED ON HR MTSAT IR IMAGERY AND SURFACE
OBSERVATIONS. CYCLONE MOVING SOUTHEAST AT ABOUT 05 KTS. MAXIMUM 10
MINUTE AVERAGE WINDS NEAR THE CENTRE ESTIMATED AT ABOUT 35 KNOTS.

EXPECT WINDS OVER 33 KNOTS WITHIN 150 NAUTICAL MILES IN N SEMICIRCLE,
WITHIN 090 NAUTICAL MILES IN SE QUADRANT,
AND WITHIN 120 NAUTICAL MILES IN SW QUADRANT.

DEEP CONVECTION HAS INCREASED WITH BANDS WRAPPING AROUND LLCC.
ORGANIZATION HAS IMPROVED IN THE PAST 24 HOURS. CYCLONIC CIRCULATION
EXTENDS TO 250HPA. SST AROUND 31 DEGREES CELSIUS. SYSTEM LIES UNDER
AN UPPER HIGH IN A LOW SHEARED ENVIRONMENT. OUTFLOW GOOD. SYSTEM IS
BEING STEERED TO THE SOUTHEAST BY A NORTHWESTERLY DEEP LAYER
MEANFLOW. DVORAK ANALYSIS BASED ON 0.65 WRAP YIELDS DT=3.0. MET AND
PT AGREE. THUS, YIELDING T3.0/3.0/D1.5/24HRS.

GLOBAL MODELS MOVE THE SYSTEM SOUTHEASTWARDS WITH FURTHER
INTENSIFICATION.
...

[Nev]

JTWC are expecting TC Winston to get close to Cat 4 on Saturday, compared to RSMC Nadi's Cat 2…

WTPS31 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 11P (ELEVEN) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 11P (ELEVEN) WARNING NR 002
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
110000Z --- NEAR 15.7S 171.1E
MOVEMENT PAST SIX HOURS - 155 DEGREES AT 04 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
…
REMARKS:
110300Z POSITION NEAR 16.0S 171.2E.
TROPICAL CYCLONE 11P (ELEVEN), LOCATED APPROXIMATELY 443 NM WEST-
NORTHWEST OF SUVA, FIJI, HAS TRACKED SOUTH-SOUTHEASTWARD AT 04
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS DEEPENED CONVECTION WITH TIGHTENING SPIRAL BANDING.
A 102204Z AMSU-B 89 GHZ MICROWAVE IMAGE DEPICTS A SYMMETRIC LOW
LEVEL CIRCULATION CENTER WITH DEEP CONVECTION ON THE NORTHERN AND
WESTERN PERIPHERIES GIVING HIGH CONFIDENCE TO THE INITIAL POSITION.
THE INITIAL INTENSITY OF 40 KNOTS IS BASED ON DVORAK ESTIMATES FROM
MULTIPLE AGENCIES IN CLOSE AGREEMENT. TC 11P IS CURRENTLY POSITIONED
OVER WARM SEA SURFACE TEMPERATURES (31 CELSIUS) AND HAS VERY GOOD
RADIAL OUTFLOW WITH 20 KNOTS OF VERTICAL WIND SHEAR INDICATING THE
POTENTIAL FOR SIGNIFICANT DEVELOPMENT OVER THE FORECAST PERIOD,
PEAKING AT 100 KNOTS BY TAU 48. TC 11P IS FORECASTED TO TRACK
POLEWARD ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE THROUGH
TAU 72. AFTER TAU 72 TC 11P IS EXPECTED TO ROUND THE RIDGE AXIS
TAKING AN EASTERN TRACK. DYNAMIC MODEL GUIDANCE IS IN RELATIVELY
GOOD AGREEMENT GIVING HIGH CONFIDENCE TO THE FORECAST TRACK AND
INTENSITY. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 110000Z IS 12 FEET.
NEXT WARNINGS AT 111500Z AND 120300Z. REFER TO TROPICAL CYCLONE 12P
(TWELVE) WARNINGS (WTPS32 PGTW)
FOR SIX-HOURLY UPDATES.
...

[Nev]

TC Tatiana in the Coral Sea was named by the BoM this evening…

Australian Government Bureau of Meteorology
Queensland Region
Tropical Cyclone Warning Centre

TROPICAL CYCLONE INFORMATION BULLETIN
For 6:56 pm EST on Thursday the 11th of February 2016

At 4 pm AEST Thursday, Tropical Cyclone Tatiana (Category 1) with central
pressure 994 hPa was located over the central Coral Sea near latitude 16.9 south
longitude 157.9 east, which is about 1030 km east northeast of Mackay.

The cyclone is moving east southeast at about 14 kilometres per hour, and a
curve onto a southeasterly track is expected through the remainder of today into
Friday. This is likely to take the system out of the Queensland region late on
Friday or Saturday morning.

It is likely that the system will continue to strengthen overnight and during
Friday.

The system is located well offshore and expected to move further away; it does
not pose a threat to the Queensland coast.

[Nev]

RSMC Nadi now have Winston as a Cat 3 by Saturday

TROPICAL DISTURBANCE ADVISORY NUMBER A5 ISSUED FROM RSMC NADI
Feb 110753 UTC.

TROPICAL CYCLONE WINSTON CENTRE 990HPA CATEGORY 1 WAS LOCATED NEAR
16.2S 171.4E AT 110600 UTC. POSITION POOR BASED ON HR MTSAT IR
IMAGERY AND SURFACE OBSERVATIONS. CYCLONE MOVING SOUTH-SOUTHEAST AT
ABOUT 05 KTS. MAXIMUM 10 MINUTE AVERAGE WINDS NEAR THE CENTRE
ESTIMATED AT ABOUT 40 KNOTS.
…
DEEP CONVECTION PERSISTENT WITH BANDS TIGHTLY WRAPPING AROUND LLCC.
ORGANIZATION HAS IMPROVED IN THE PAST 24 HOURS. SST AROUND 31 DEGREES
CELSIUS. SYSTEM LIES UNDER AN UPPER HIGH IN A LOW TO MODERATE SHEARED
ENVIRONMENT. OUTFLOW GOOD. SYSTEM IS BEING STEERED TO THE
SOUTH-SOUTHEAST BY THE NORTH-NORTHWEST DEEP LAYER MEANFLOW. DVORAK
ANALYSIS BASED ON 0.65 WRAP YIELDS DT=3.0. MET AND PT AGREE. THUS,
YIELDING T3.0/3.0/D1.5/24HRS.

GLOBAL MODELS MOVE THE SYSTEM SOUTH-SOUTHEASTWARDS WITH FURTHER
INTENSIFICATION.
...

[NZ Thunderstorm Soc]

Is this before it starts to "Peters" out?

[Nev]

This evening's JTWC and BoM remarks for Tatiana…

WTPS32 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL CYCLONE 12P (TATIANA) WARNING NR 002
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
110600Z --- NEAR 16.9S 157.9E
MOVEMENT PAST SIX HOURS - 090 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
…
REMARKS:
110900Z POSITION NEAR 17.0S 158.2E. TROPICAL CYCLONE 12P (TATIANA),
LOCATED APPROXIMATELY 559 NM WEST-NORTHWEST OF NOUMEA, NEW
CALEDONIA, HAS TRACKED EASTWARD AT 05 KNOTS OVER THE PAST SIX HOURS.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN AREA OF DEEP
CONVECTION WRAPPING TIGHTLY INTO A COMPACT LOW LEVEL CIRCULATION
CENTER (LLCC), WITH MOST OF THE CONVECTION BEING CONFINED TO THE
WESTERN SEMICIRCLE. AN 110551Z SSMIS 91GHZ MICROWAVE IMAGE DEPICTS
WELL DEFINED LOW LEVEL CLOUD BANDS AND A WEAK MICROWAVE EYE FEATURE,
SUPPORTING THE INITIAL POSITION WITH HIGH CONFIDENCE. THE INITIAL
INTENSITY IS BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T3.0 (45
KNOTS) FROM BOTH KNES AND PGTW WITH HIGH CONFIDENCE. UPPER-LEVEL
ANALYSIS CONTINUES TO INDICATE THE PRESENCE OF A STRONG POLEWARD
OUTFLOW CHANNEL, BEING PROVIDED BY AN UPSTREAM UPPER LEVEL TROUGH,
AND MODERATE (15 TO 20 KNOTS) VERTICAL WIND SHEAR (VWS). THE PRIMARY
STEERING MECHANISM FOR TC 12P IS CURRENTLY A WEAKENING INDUCED RIDGE
POSITIONED BETWEEN TC 11P (WINSTON) AND TC TATIANA, WHICH IS
ALLOWING TC TATIANA TO MOVE GENERALLY EAST-SOUTHEASTWARD. BY TAU 24
THIS INDUCED RIDGE WILL DISSIPATE AND THE PRIMARY STEERING MECHANISM
WILL BECOME THE DEEP-LAYER SUBTROPICAL RIDGE EAST OF THE SYSTEM,
TURNING TC TATIANA SOUTHWARD. TC TATIANA REMAINS IN A REGION OF HIGH
SEA SURFACE TEMPERATURE (SST), COMBINED WITH RELATIVELY LOW VERTICAL
WIND SHEAR, ALLOWING FOR A SHORT INTENSIFICATION PHASE FOR THE NEXT
12-24 HOURS. THEREAFTER, INCREASING VWS, COUPLED WITH INCREASINGLY
UNFAVORABLE SSTS, WILL BEGIN TO RAPIDLY WEAKEN TC TATIANA BEFORE THE
SYSTEM BECOMES COMPLETELY ABSORBED WITHIN THE UPPER LEVEL TROUGH BY
TAU 72. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT FOR THE FIRST 24
HOURS. AFTER 24 HOURS, MODEL GUIDANCE UNCERTAINTY INCREASES AS TC
TATIANA INTERACTS WITH THE UPPER LEVEL TROUGH, GIVING MODERATE
CONFIDENCE TO THE FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
110600Z IS 15 FEET. NEXT WARNINGS AT 112100Z AND 120900Z. REFER TO
TROPICAL CYCLONE 11P (WINSTON) WARNINGS (WTPS31 PGTW) FOR TWELVE-
HOURLY UPDATES.//

IDQ20018
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by BRISBANE TROPICAL CYCLONE WARNING CENTRE
at: 0912 UTC 11/02/2016
Name: Tropical Cyclone Tatiana
Identifier: 10U
Data At: 0600 UTC
Latitude: 16.9S
Longitude: 157.9E
Location Accuracy: within 30 nm (55 km)
Movement Towards: east southeast (121 deg)
Speed of Movement: 8 knots (14 km/h)
Maximum 10-Minute Wind: 35 knots (65 km/h)
Maximum 3-Second Wind Gust: 50 knots (95 km/h)
Central Pressure: 994 hPa
…
REMARKS:
Location fix based primarily on animated visible imagery. Convection and
curvature of the system has continued to improve during the day, however some
evidence of NE wind shear is still evident due to the more limited convection in
the NE quadrant. Dvorak analysis based on curved band pattern with an 0.6 wrap
giving DT3.0. MET supports. Final T 3.0.

Recent motion has been to the ESE at about 8 knots, primarily under the
influence of low level monsoon flow to the north, and a mid level shortwave
trough to the south. The system is expected to curve to the southeast in the
next 12 to 24 hours, as the shortwave trough to the south lifts out to the
southeast, a second shortwave trough develops over eastern Queensland, and some
indirect interaction with Winston east of Vanuatu develops, manifest as
shortwave low to mid level ridging developing between the two systems.

The system remains in an environment marginally supportive of further
development, ample ocean heat content, and moderate northerly vertical wind
shear persisting for the next 24 hours or so. This should lead to at least
modest further strengthening overnight into Friday. Following this, vertical
shear is forecast to increase over the system as the second stronger shortwave
trough over eastern Queensland spreads its influence over the system, which
should lead to a weakening or at least a loss of tropical characteristics during
Saturday.

[Nev]

Tatiana may get to Cat 2 overnight tonight before undergoing ETT tomorrow or Sunday according to both the BoM and JTWC…

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by BRISBANE TROPICAL CYCLONE WARNING CENTRE
at: 1251 UTC 11/02/2016
Name: Tropical Cyclone Tatiana
Identifier: 10U
Data At: 1200 UTC
Latitude: 17.0S
Longitude: 158.1E
Location Accuracy: within 45 nm [85 km]
Movement Towards: east southeast [120 deg]
Speed of Movement: 5 knots [9 km/h]
Maximum 10-Minute Wind: 40 knots [75 km/h]
Maximum 3-Second Wind Gust: 55 knots [100 km/h]
Central Pressure: 992 hPa
…
REMARKS:
Tropical cyclone Tatiana is currently moving towards the east-southeast under
the combined influence of westerly monsoon flow to the north of the system and a
short wave trough passing to the southeast of the system. An amplifyling upper
trough is expected to move into the western Coral Sea during Friday and as a
result should become the primary steering influence on Tatiana. This approaching
upper trough should lead to Tatiana adopting a track towards the southeast
during Friday.

The latetst Dvorak analysis was based on a curved band pattern with a 0.6 degree
wrap and added 0.5 for white band, giving a DT of 3.5. MET and PAT were 3.5 and
3.0 respectively. FT was based on PAT as the DT was not clear. Confidence in the
location of the low level centre is rated as fair. The latest ASCAT-B image at
1036UTC supports this analysis with winds of 40 knots near the centre of the
system.

Tatiana remains in an environment supportive of further development with ample
ocean heat content and moderate northeasterly vertical wind shear. Given the
environment is expected to remain fairly similar into Friday this should lead to
at least modest intensification over the next 24 hours, possibly even allowing
the system to reach category 2 strength by Friday night. Moving into Saturday,
vertical wind shear is forecast to increase over the system as the upper trough
moving over the Coral Sea spreads its influence over the system, which should
lead to a weakening or at least a loss of tropical characteristics by Saturday
afternoon. Some of the compuer model guidance indicate that Tatiana may continue
as a shallow, warm cored system with some gales into Sunday.

WTPS32 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL CYCLONE 12P (TATIANA) WARNING NR 002
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
110600Z --- NEAR 16.9S 157.9E
MOVEMENT PAST SIX HOURS - 090 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
…
REMARKS:
110900Z POSITION NEAR 17.0S 158.2E. TROPICAL CYCLONE 12P (TATIANA),
LOCATED APPROXIMATELY 559 NM WEST-NORTHWEST OF NOUMEA, NEW
CALEDONIA, HAS TRACKED EASTWARD AT 05 KNOTS OVER THE PAST SIX HOURS.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN AREA OF DEEP
CONVECTION WRAPPING TIGHTLY INTO A COMPACT LOW LEVEL CIRCULATION
CENTER (LLCC), WITH MOST OF THE CONVECTION BEING CONFINED TO THE
WESTERN SEMICIRCLE. AN 110551Z SSMIS 91GHZ MICROWAVE IMAGE DEPICTS
WELL DEFINED LOW LEVEL CLOUD BANDS AND A WEAK MICROWAVE EYE FEATURE,
SUPPORTING THE INITIAL POSITION WITH HIGH CONFIDENCE. THE INITIAL
INTENSITY IS BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T3.0 (45
KNOTS) FROM BOTH KNES AND PGTW WITH HIGH CONFIDENCE. UPPER-LEVEL
ANALYSIS CONTINUES TO INDICATE THE PRESENCE OF A STRONG POLEWARD
OUTFLOW CHANNEL, BEING PROVIDED BY AN UPSTREAM UPPER LEVEL TROUGH,
AND MODERATE (15 TO 20 KNOTS) VERTICAL WIND SHEAR (VWS). THE PRIMARY
STEERING MECHANISM FOR TC 12P IS CURRENTLY A WEAKENING INDUCED RIDGE
POSITIONED BETWEEN TC 11P (WINSTON) AND TC TATIANA, WHICH IS
ALLOWING TC TATIANA TO MOVE GENERALLY EAST-SOUTHEASTWARD. BY TAU 24
THIS INDUCED RIDGE WILL DISSIPATE AND THE PRIMARY STEERING MECHANISM
WILL BECOME THE DEEP-LAYER SUBTROPICAL RIDGE EAST OF THE SYSTEM,
TURNING TC TATIANA SOUTHWARD. TC TATIANA REMAINS IN A REGION OF HIGH
SEA SURFACE TEMPERATURE (SST), COMBINED WITH RELATIVELY LOW VERTICAL
WIND SHEAR, ALLOWING FOR A SHORT INTENSIFICATION PHASE FOR THE NEXT
12-24 HOURS. THEREAFTER, INCREASING VWS, COUPLED WITH INCREASINGLY
UNFAVORABLE SSTS, WILL BEGIN TO RAPIDLY WEAKEN TC TATIANA BEFORE THE
SYSTEM BECOMES COMPLETELY ABSORBED WITHIN THE UPPER LEVEL TROUGH BY
TAU 72. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT FOR THE FIRST 24
HOURS. AFTER 24 HOURS, MODEL GUIDANCE UNCERTAINTY INCREASES AS TC
TATIANA INTERACTS WITH THE UPPER LEVEL TROUGH, GIVING MODERATE
CONFIDENCE TO THE FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
110600Z IS 15 FEET. NEXT WARNINGS AT 112100Z AND 120900Z.