Topic: Tropical Cyclone Atu - RSMC Nadi TCWC

[Simon McCombe]

Hi everyone. A new tropical depression advisory from, and courtesy of, RSMC Nadi Tropical Cyclone Warning Centre as at yesterday (18/02/2011). With it having moderately favourable conditions (sitting near a surface trough and moderate shear,along with SST's around 30 degrees C.), there is a high chance of developing into a TC. Currently slow moving SSE and predicted to stay on this track, but as we all know, could turn any direction but will usually swing more towards the west. Former TC Yasi developed in approximately the same co-ordinates.                                                                                                                                                                                                                                        TROPICAL DISTURBANCE ADVISORY NUMBER A4 ISSUED FROM RSMC NADI
Feb 18/1946 UTC 2011 UTC.

TROPICAL DEPRESSION 11F CENTRE 997 HPA WAS LOCATED NEAR 15.6S 169.6E
AT 181800 UTC.
POSITION POOR BASED ON MTSAT IR IMAGERY AND PERIPHERAL SURFACE
OBSERVATIONS.  DEPRESSION SLOW MOVING. MAXIMUM 10-MINUTE AVERAGE
WINDS NEAR THE CENTRE ESTIMATED AT ABOUT 30 KNOTS.  

 
ORGANISATION IMPROVED PAST 24 HOURS WITH PRIMARY BANDS TRYING TO WRAP
AROUND LLCC. CONVECTION HAS INCREASED PAST 12 HOURS DUE TO DIURNAL
VARIATION MAKING LLCC CLOUD FILLED. CYCLONIC CIRCULATION EXTENDS TO
500HPA. SST AROUND 30 DEGREE CELSIUS. SYSTEM LIES ALONG A SURFACE
TROUGH UNDER AN UPPER DIFFLUENT REGION IN A MODERATE SHEARED
ENVIRONMENT. SYSTEM IS BEING STEERED SOUTH-SOUTHEAST BY A WEAK
NORTHWEST DEEP LAYER MEAN REGIME. MID-LEVEL RIDGE TO SOUTH OF SYSTEM
IS EXPECTED TO WEAKEN AND RECEDE TO THE WEST AS SYSTEM MOVES SOUTH.
DVORAK ASSESMENT BASED ON 0.40 WRAP ON LOG 10 SPIRAL YIELDING DT=2.5,
MET=2.5 PT=2.5 FT BASED ON DT, THUS T2.5/2.5/D1.0/24HRS.
GLOBAL MODELS ARE GRADUALLY DEVELOPING THE DEPRESSION AND MAINTAINING
A SSE TRACK. POTENTIAL FOR THE SYSTEM TO DEVELOP INTO A TROPICAL
CYCLONE IN THE NEXT 24 HOURS IS HIGH.

FORECAST:
AT 12 HRS VALID AT 190600 UTC 16.3S 169.6E MOV S AT 04 KT WITH 35 KT
CLOSE TO CENTRE
AT 24 HRS VALID AT 191800 UTC 17.0S 169.7E MOV SSE AT 03 KT WITH 40
KT CLOSE TO CENTRE

OUTLOOK :
AT 36 HRS VALID AT 200600 UTC 17.5S 170.0E MOV SSE AT 03 KT WITH 45
KT CLOSE TO CENTRE
AT 48 HRS VALID AT 201800 UTC 18.1S 170.4E MOV SSE AT 04 KT WITH 50
KT CLOSE TO CENTRE

THE NEXT TROPICAL DISTURBANCE ADVISORY ON TD 11F WILL BE ISSUED AT
AROUND 190200 UTC OR EARLIER.

[Simon McCombe]

Hi everyone. This tropical low has now formed into TC Atu. Currently a category 1 (987 hPa) and intensifying. Slow moving on a SSW track and will not affect Australia at this time. Issued by and courtesy of RSMC Nadi TCWC on 19/02/2011 1915 UTC and re-issued by BoM Brisbane.                                                         IDQ20080
40:2:2:24:16S154E999:11:00
Australian Government Bureau of Meteorology
Queensland


STORM WARNING 012 ISSUED FROM RSMC NADI Feb 19/1915 UTC 2011 UTC.

TROPICAL CYCLONE ATU CENTRE 987HPA CATEGORY 1 WAS LOCATED NEAR 16.7
SOUTH 169.2 EAST AT 191800UTC.
POSITION POOR.
REPEAT POSITION 16.7S 169.2E AT 191800 UTC.
CYCLONE MOVING SOUTH-SOUTHWEST AT 03 KNOTS. CYCLONE INTENSIFYING.
EXPECT SUSTAINED WINDS OF 45 KNOTS CLOSE TO THE CENTRE INCREASING TO
55 KNOTS WITHIN THE NEXT 6 TO 12 HOURS.
EXPECT WINDS OVER 33 KNOTS WITHIN 180 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 100 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 35 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 35 NAUTICAL MILES IN NW QUADRANT.

FORECAST POSITION NEAR 17.3S 169.3E AT 200600 UTC
              AND NEAR 17.8S 169.5E AT 201800 UTC.

ALL VESSELS WITHIN 300 NAUTICAL MILES OF CENTRE ARE REQUESTED TO SEND
REPORTS EVERY THREE HOURS TO RSMC NADI. VOS REPORTING SHIPS USE
NORMAL CHANNELS. OTHER VESSELS FAX PLUS 679 6720190 OR EMAIL NADITCC
AT MET DOT GOV DOT FJ.


THIS WARNING CANCELS AND REPLACES WARNING 011.

RE-ISSUED BY THE BUREAU OF METEOROLOGY, BRISBANE.

[Colin Maitland]

GFS has had an eye on this system for a several days now. Due to the steering influence dominating our waters and those of 160deg + east, the current modeling has it heading South/southeast and moving well to the north of New Zealand around Thursday the 24/02/2011.



This is in line with the forecast track map issued by JTWC

[Richary]

Now a Cat 4, glad the forecast track is keeping it away from us as a slight chance I have to go to Qld next week!