WTXS21 PGTW 251830
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97S) CANCELLATION//
REF/A/MSG JOINT TYPHOON WRNCEN PEARL HARBOR HI/242051ZDEC2021//
AMPN/REF IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. REMARKS: THIS CANCELS REF A (WTXS PGTW 242100). THE AREA OF
CONVECTION (INVEST 97S) PREVIOUSLY LOCATED NEAR 11.5S 130.5E IS NOW
LOCATED NEAR 12.9S 130.4E, APPROXIMATELY 37 NM SOUTHWEST OF DARWIN,
AUSTRALIA. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
DEPICTS A BROAD AREA OF SOMEWHAT ORGANIZED CONVECTION ROTATING
AROUND AN ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC). RADAR
ANALYSIS INDICATES THAT INVEST 97S HAS MADE LANDFALL ALONG THE
WESTERN SHORE OF THE TOP END REGION OF AUSTRALIA. ALBEIT OVER LAND,
JTWC HAS DOWNGRADED THE INVEST TO A LOW. GLOBAL MODELS AGREE THAT
THE VORTEX WILL TRACK TO THE EAST-SOUTHEAST WITH THE SLIGHT
POSSIBILITY OF RE-INTENSIFICATION OVER THE GULF OF CARPENTARIA IN
APPROXIMATELY 48-72 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 998 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS DOWNGRADED
TO LOW. //
NNNN
ABIO10 PGTW 270800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN
/REISSUED/270800Z-271800ZDEC2021//
RMKS/
1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH INDIAN OCEAN AREA (135E WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 97S) PREVIOUSLY LOCATED
NEAR 14.6S 131.2E IS NOW LOCATED NEAR 13.9S 132.5E, APPROXIMATELY
130 NM SOUTHEAST OF DARWIN. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
AND A 270438Z AMSR2 89GHZ COMPOSITE MICROWAVE IMAGE DEPICT A BROAD
LOW-LEVEL CIRCULATION CENTER (LLCC) WITH FORMATIVE CONVECTIVE
BANDING OVER THE NORTHERN AND SOUTHERN SEMICIRCLES. ANIMATED RADAR
IMAGERY FROM THE WARRUWI RADAR INDICATES MULTIPLE CONVECTIVE BANDS
OVER THE NORTHERN SEMICIRCLE WRAPPING INTO THE LLCC. THESE BANDS ARE
ASSOCIATED WITH VIGOROUS, CONVERGENT WESTERLY TO WEST-NORTHWESTERLY
FLOW AT 20 TO 25 KNOTS. SURFACE OBSERVATIONS FROM TINDAL (14.52S
132.38E), NEAR THE CENTER, REVEAL SOUTHEASTERLY GUSTS OF 20-25 KNOTS
WITH SLP NEAR 999MB. UPPER-LEVEL CONDITIONS ARE FAVORABLE WITH
ROBUST POLEWARD OUTFLOW AND LOW TO MODERATE VERTICAL WIND SHEAR.
FRICTIONAL EFFECTS OVER LAND ARE THE PRIMARY HINDRANCE, HOWEVER, THE
SYSTEM IS EXPECTED TO TRACK EASTWARD OVER THE GULF OF CARPENTARIA
WITHIN THE NEXT 24 TO 36 HOURS WITH POTENTIAL FOR DEVELOPMENT OF A
TROPICAL CYCLONE POSSIBLE BEFORE THE SYSTEM TRACKS OVER THE CAPE
YORK PENINSULA NEAR TAU 48 (29/06Z). REINTENSIFICATION IS LIKELY
AGAIN AFTER TAU 72 WHEN INVEST 97S TRACKS OVER THE CORAL SEA WITH
UPPER-LEVEL SUBTROPICAL WESTERLIES AIDING IN THE GRADUAL
STRENGTHENING TREND. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED
AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE
NEAR 999 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.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA. 2.B.(1) TO
MEDIUM.//
NNNN
ABPW10 PGTW 281800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS REISSUED/281800Z-290600ZDEC2021//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
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
(INVEST 97S) PREVIOUSLY LOCATED NEAR 13.9S 132.5E IS NOW LOCATED
NEAR 16.1S 130.9E,APPROXIMATELY 20 NM NORTH OF MORNINGTON ISLAND.
ANIMATED ENHANCED INFRARED SATELLITE, COMPOSITE RADAR REFLECTIVITY
FROM ABOM, AND RECENT ASCAT DATA DEPICT A BROAD AND GROSSLY
ELONGATED LOW-LEVEL CIRCULATION (LLC) THAT
STRETCHES ACROSS THE SOUTHERN GULF OF CARPENTARIA (GOC). THE MAIN
CONVECTION IS SHEARED SOUTHEASTWARD OF THE LLC. ENVIRONMENTAL
ANALYSIS INDICATES MARGINAL CONDITIONS FOR DEVELOPMENT WITH VERY
WARM (30-31C) SEA SURFACE TEMPERATURES AND ROBUST POLEWARD OUTFLOW
OFFSET BY MODERATE (15-20KT) RELATIVE VERTICAL WIND SHEAR AND CLOSE
PROXIMITY TO LAND. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT
THE SYSTEM WILL TRACK EAST-SOUTHEASTWARD OVER THE REMAINDER OF THE
GOC, ACROSS CAPE YORK PENINSULA, AND EXIT INTO THE CORAL SEA NEAR
CAIRNS WITHIN THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS
ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 997 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS
MEDIUM.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: TRANSFERRED THE AREA IN PARA 2.B(1)
TO THE ABPW.//
NNNN
A tropical low, located in the eastern Gulf of Carpentaria, near 15S 140.5E at 2pm AEST is moving eastwards at 30 km/h. The low will move into the Coral Sea during Thursday and track to the east southeast and then more to the south on the weekend. Southeasterly gales are possible between the low and the coast during this time, however, at this stage it has only a low chance of reaching tropical cyclone intensity in the Coral Sea. The system may develop further into Sunday and early next week but will be developing sub-tropical characteristics as it moves outside the tropics.
Likelihood of a tropical cyclone in the Eastern Region on:
Thursday: Low
Friday: Low
Saturday: Low
WTPS21 PGTW 300230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 17.0S 146.9E TO 19.2S 152.3E
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,
SYNOPTIC DATA AND RADAR DATA AT 300200Z INDICATE THAT A CIRCULATION
CENTER IS LOCATED NEAR 17.2S 147.3E. THE SYSTEM IS MOVING EAST-
SOUTHEASTWARD AT 11 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97S) PREVIOUSLY LOCATED
NEAR 16.6S 142.6E IS NOW LOCATED NEAR 17.2S 147.3E, APPROXIMATELY
92NM EAST-SOUTHEAST OF CAIRNS, AUSTRALIA. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY AND ANIMATED RADAR IMAGERY FROM THE CAIRNS RADAR
DEPICT A CONSOLIDATING SYSTEM WITH IMPROVED CONVECTIVE BANDING
WRAPPING INTO A BROAD LOW-LEVEL CIRCULATION CENTER (LLCC). A 292044Z
SSMIS 37GHZ MICROWAVE IMAGE INDICATES DISORGANIZED LOW-LEVEL BANDING
WITH A WEAKLY-DEFINED LLCC. A RECENT SCATTEROMETER IMAGE REVEALS AN
ELONGATED CIRCULATION WITH 25 TO 30 KNOT WINDS. THIS SYSTEM IS A
HYBRID SYSTEM WITH BOTH SUBTROPICAL AND TROPICAL CHARACTERISTICS,
AND IS LOCATED JUST NORTH OF A SUBTROPICAL JET. UPPER-LEVEL FEATURE
TRACK WINDS INDICATE A DEVELOPING ANTICYCLONE OVER THE SYSTEM WITH
IMPROVED EQUATORWARD AND POLEWARD OUTFLOW. ADDITIONALLY, VERTICAL
WIND SHEAR (VWS) HAS DECREASED FROM MODERATE TO LOW (10-15 KNOTS)
OVER THE PAST 12 HOURS. SEA SURFACE TEMPERATURES ARE CONDUCIVE AT 30-
31C. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN MARGINALLY-
FAVORABLE FOR ABOUT 24 TO 36 HOURS AS THE SYSTEM TRACKS EAST-
SOUTHEASTWARD, WHICH MAY ALLOW FOR FURTHER CONSOLIDATION. AFTER THIS
SHORT WINDOW, THE SYSTEM WILL TRACK SOUTHEASTWARD UNDER INCREASING
VWS (30-40 KNOTS) WITH SLIGHTLY COOLER SST VALUES, AND IS FORECASTED
TO TRANSITION TO A SUBTROPICAL GALE-FORCE LOW AFTER TAU 48. 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
310230Z.//
NNNN
WTPS21 PGTW 310230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97S) CANCELLATION//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/300221ZDEC2021//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. REMARKS:
THIS CANCELS REF A (WTPS PGTW 300230). THE AREA OF CONVECTION
(INVEST 97S) PREVIOUSLY LOCATED NEAR 17.2S 147.3E IS NOW LOCATED
NEAR 19.5S 150.2E, APPROXIMATELY 388 NM EAST-SOUTHEAST OF CAIRNS,
AUSTRALIA. THE SYSTEM IS CURRENTLY CLASSIFIED AS A SUBTROPICAL
STORM, GENERALLY CHARACTERIZED AS HAVING BOTH TROPICAL AND MID-
LATITUDE CYCLONE FEATURES. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
AND ANIMATED RADAR IMAGERY FROM THE CAIRNS RADAR DEPICT A
CONSOLIDATING SYSTEM WITH CONVECTIVE BANDING WRAPPING INTO A BROAD
LOW-LEVEL CIRCULATION CENTER (LLCC). A 302031Z SSMIS 91GHZ MICROWAVE
IMAGE INDICATES DISORGANIZED LOW-LEVEL BANDING WITH A WEAKLY-DEFINED
LLCC. THIS SYSTEM IS LOCATED JUST NORTH OF A SUBTROPICAL JET. UPPER-
LEVEL FEATURE TRACK WINDS INDICATE A DEVELOPING ANTICYCLONE OVER THE
SYSTEM WITH IMPROVED EQUATORWARD AND POLEWARD OUTFLOW. ADDITIONALLY,
VERTICAL WIND SHEAR (VWS) HAS REMAINED MODERATE TO LOW (10-15 KTS).
SEA SURFACE TEMPERATURES ARE CONDUCIVE AT 29-30C. GLOBAL MODELS
INDICATE THE SYSTEM WILL TRACK SOUTHEASTWARD UNDER INCREASING VWS
(40-50 KTS) WITH SLIGHTLY COOLER SST VALUES, AND IS FORECASTED TO
TRANSITION TO A SUBTROPICAL GALE-FORCE LOW AFTER TAU 24. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. FOR HAZARDS AND
WARNINGS, REFERENCE FLEET WEATHER CENTER SAN DIEGO HIGH WINDS AND
SEAS PRODUCT OR REFER TO LOCAL WMO DESIGNATED FORECAST AUTHORITY.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS DOWNGRADED TO MEDIUM.
//
NNNN
TROPICAL CYCLONE WARNING CENTRE
IDQ20018
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 0519 UTC 31/12/2021
Name: Tropical Cyclone Seth
Identifier: 08U
Data At: 0300 UTC
Latitude: 19.7S
Longitude: 153.7E
Location Accuracy: within 25nm (45 km)
Movement Towards: southeast (124 deg)
Speed of Movement: 14 knots (27 km/h)
Maximum 10-Minute Wind: 45 knots (85 km/h)
Maximum 3-Second Wind Gust: 60 knots (110 km/h)
Central Pressure: 992 hPa
Radius of 34-knot winds NE quadrant: 120 nm (220 km)
Radius of 34-knot winds SE quadrant: 140 nm (260 km)
Radius of 34-knot winds SW quadrant: 140 nm (260 km)
Radius of 34-knot winds NW quadrant: 80 nm (150 km)
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: nm ( km)
Radius of Maximum Winds: 30 nm (55 km)
Dvorak Intensity Code: T3.0/3.0/D1.5/24HRS STT: D0.5/06HRS
Pressure of outermost isobar: 1002 hPa
Radius of outermost closed isobar: 180 nm (335 km)
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
(UTC) : degrees : nm (km): knots(km/h): hPa
+06: 31/0900: 20.2S 154.9E: 035 (065): 045 (085): 990
+12: 31/1500: 20.6S 155.9E: 045 (085): 045 (085): 990
+18: 31/2100: 21.1S 156.8E: 055 (100): 045 (085): 988
+24: 01/0300: 21.8S 157.6E: 070 (130): 045 (085): 988
+36: 01/1500: 23.6S 158.7E: 100 (185): 045 (085): 988
+48: 02/0300: 25.9S 158.9E: 130 (240): 050 (095): 985
+60: 02/1500: 26.8S 158.4E: 160 (295): 045 (085): 986
+72: 03/0300: 27.2S 157.9E: 190 (350): 040 (075): 988
+96: 04/0300: 26.6S 157.0E: 255 (475): 040 (075): 990
+120: 05/0300: 26.5S 156.3E: 340 (630): 035 (065): 991
REMARKS:
Tropical Cyclone Seth has formed in the Coral Sea, aided by strong synoptic
forcing from both the northwesterly monsoon northeast of the centre and east
southeast trade flow to the south. The centre tracked close to Marion Island at
23UTC where gales have since been recorded while Frederick Reef to the south
has been experiencing gales. Intensity estimate at 45kn based upon these
observations.
Despite upper level northwesterly flow over the circulation the convective
signature improved dramatically overnight with curved band wrap estimated at
0.7 in recent hours to indicate Dvorak DT=3.0, though MET=2.5; FT/CI=3.0.
The northwesterly wind shear should increase in the next 36 hours which will
likely weaken the convective signature, however synoptic enhancement of the
surface winds are reflected in NWP guidance to sustain gales. By late Saturday
(+36h) a mid-latitude upper level low will approach and intensify the surface
circulation through baroclinic processes peaking on Sunday (+48h) when it will
have 'hybrid' tropical/sub-tropical characteristics over SSTs of ~26C.
The system is being steered to the east southeast under the deep NW flow. A
more southerly track is expected later Sunday with the upper low's approach and
then will slow on Sunday (+48h) and then meander with weak steering.
By Monday the system should gradually weaken following the passage of the upper
low and have transitioned from being tropical to be classified as a
sub-tropical low. Gales persist to the south and west for longer. There is a
considerable spread of track possibilities at this range including a drift
towards the eastern Australian coastline.
The most significant hazard to coastal communities is large waves that could
affect a significant stretch of coastline over the duration of this event.
Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 31/0730 UTC
