Updated: 17 June 2020
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| Tropical Cyclones
[Index] | Tropical Cyclone ALENGA : JTWC Advisories |
| Season 2011-2012 Summaries (Operational Data): [AU] [SIO] [SPAC] [SH] | |
| ---> Tropical Cyclone ALENGA Track Map and Data |
WTXS22 PGTW 20111203 20:30z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/030821DEC2011//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 10.4S 94.2E TO 13.6S 88.8E
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 27 TO 32 KNOTS. METSAT IM-
AGERY AT 032030Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.2S 93.6E. THE SYSTEM IS MOVING SOUTHWESTWARD AT 10
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.2S
93.1E IS NOW LOCATED NEAR 11.3S 93.4E, APPROXIMATELY 200 NM WEST OF
THE COCOS ISLANDS. RECENT ANIMATED INFRARED SATELLITE IMAGERY SHOWS
INCREASED CONVECTIVE CONSOLIDATION OVER AN INCREASINGLY MORE
ORGANIZED LOW LEVEL CIRCULATION CENTER. MICROWAVE IMAGERY (031216Z
SSMIS AND 031604 AMSU) SHOWS DEEPENING CONVECTION WRAPPING INTO THE
SYSTEM CENTER FROM THE SOUTHWEST. RECENT SCATTEROMETRY DATA
INDICATES 30 KNOT WINDS NEAR THE SYSTEM CENTER AND ANIMATED WATER
VAPOR IMAGERY SHOWS IMPROVED OUTFLOW IN ALL QUADRANTS. UPPER LEVEL
ANALYSIS INDICATES THAT THE LLCC IS LOCATED JUST NORTH OF THE
SUBTROPICAL RIDGE AXIS IN AN AREA OF MODERATE VERTICAL WIND SHEAR
(VWS). AS THE SYSTEM CONTINUES TO TRACK SOUTHWESTWARD, VWS SHOULD
RELAX AND ALLOW FOR FURTHER DEVELOPMENT. NUMERICAL MODELS CONTINUE
TO HINT AT TROPICAL CYCLONE (35 KNOTS) DEVELOPMENT WITHIN THE RANGE
OF 18 TO 48 HOURS. SEA SURFACE TEMPERATURES REMAIN FAVORABLE AT 26-
27 DEGREES CELSIUS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
27 TO 32 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED NEAR 1000
MB. DUE TO INCREASED CONSOLIDATION OF THE LLCC, RECENT SCATTEROMETRY
DATA INDICATING 30 KNOT CENTRAL WINDS, AND AN IMPROVING UPPER LEVEL
ENVIRONMENT, 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
042030Z.
4. SEE REF A FOR DETAILS ON A TROPICAL CYCLONE FORMATION ALERT
LOCATED NEAR 11.9S 68.9E.//
=========================================================================
WTXS22 PGTW 20111204 20:30z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT REISSUED//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/032021DEC2011//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
130 NM EITHER SIDE OF A LINE FROM 12.5S 90.2E TO 14.4S 85.1E
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 IM-
AGERY AT 041730Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 12.6S 89.0E. THE SYSTEM IS MOVING WESTWARD AT 12 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 12.5S
91.2E, IS NOW LOCATED NEAR 12.6S 89.0E, APPROXIMATELY 465 NM WEST OF
THE COCOS ISLANDS. ANIMATED INFRARED SATELLITE IMAGERY AND RECENT
MICROWAVE IMAGERY SHOW DEEP CONVECTION REBUILDING OVER THE LOW LEVEL
CIRCULATION CENTER AND FORMATIVE LOW LEVEL BANDING WRAPPING
INTO THE SYSTEM CENTER. ANIMATED WATER VAPOR IMAGERY INDICATES GOOD
OUTFLOW IN THE WESTERN AND SOUTHERN SEMI-CIRCLES. UPPER LEVEL
ANALYSIS REVEALS THAT THE SYSTEM IS LOCATED SLIGHTLY NORTH OF THE
RIDGE AXIS IN A REGION OF MODERATE (15-20 KNOTS) EASTERLY VERTICAL
WIND SHEAR, WHICH CONTINUES TO INHIBIT OUTFLOW ALONG THE EASTERN
SEMI-CIRCLE. SEA SURFACE TEMPERATURES ARE 26-27 DEGREES CELSIUS IN
THE AREA. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB.
DUE TO THE IMPROVING CONVECTIVE SIGNATURE AND INCREASINGLY FAVORABLE
UPPER LEVEL ENVIRONMENT, THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH.
THIS SUPERSEDES REF A.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
052030Z.//
=========================================================================
WTXS31 PGTW 20111205 03:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ONE) WARNING NR 001//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/JTWC/042021ZDEC2011//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL CYCLONE 01S (ONE) WARNING NR 001
01 ACTIVE TROPICAL CYCLONE IN SOUTH IO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
050000Z --- NEAR 12.3S 87.9E
MOVEMENT PAST SIX HOURS - 285 DEGREES AT 11 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
REPEAT POSIT: 12.3S 87.9E
---
FORECASTS:
12 HRS, VALID AT:
051200Z --- 12.6S 86.8E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 225 DEG/ 03 KTS
---
24 HRS, VALID AT:
060000Z --- 13.0S 86.4E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 130 DEG/ 05 KTS
---
36 HRS, VALID AT:
061200Z --- 13.6S 87.1E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
115 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
115 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 120 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
070000Z --- 14.4S 88.5E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 115 DEG/ 13 KTS
---
72 HRS, VALID AT:
080000Z --- 16.6S 93.3E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 120 DEG/ 13 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
090000Z --- 19.1S 98.3E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
---
REMARKS:
050300Z POSITION NEAR 12.4S 87.6E.
TROPICAL CYCLONE (TC) 01S, LOCATED APPROXIMATELY 525 NM WEST OF THE
COCOS ISLANDS, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS A RAPIDLY
CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CENTRAL
CONVECTION. A 042325Z SSMIS 37 GHZ MICROWAVE PASS SHOWS A FORMATIVE
MICROWAVE EYE AND TIGHTLY CURVED BANDING WRAPPING INTO THE LLCC. THE
CURRENT INTENSITY IS BASED ON DVORAK ESTIMATES FROM PGTW AND KNES
RANGING FROM 35 TO 45 KNOTS. THE CURRENT POSITION IS BASED ON THE
AFOREMENTIONED MICROWAVE IMAGE AND THE 042332Z PGTW SATELLITE FIX
WITH GOOD CONFIDENCE. UPPER LEVEL ANALYSIS INDICATES THAT TC 01S IS
LOCATED UNDER THE RIDGE AXIS IN A REGION OF STRONG DIFFLUENT FLOW
ALOFT AND LOW VERTICAL WIND SHEAR. ANIMATED WATER VAPOR IMAGERY
SHOWS GOOD OUTFLOW IN THE WESTERN AND SOUTHERN SEMI-CIRCLES, BUT
OUTFLOW ALONG THE EASTERN PERIPHERY IS SOMEWHAT INHIBITED BY
EASTERLY FLOW ALOFT. THE SYSTEM IS CURRENTLY TRACKING ALONG THE
NORTHWESTERN PERIPHERY OF A FINGER OF THE SUBTROPICAL RIDGE
EXTENDING FROM SOUTH OF JAKARTA INDONESIA. TC 01 IS EXPECTED TO
CONTINUE TRACKING GENERALLY WESTWARD FOR THE NEXT 12 TO 24 HOURS
BEFORE AN APPROACHING MID-LATITUDE TROUGH WEAKENS THE RIDGE AND
ALLOWS THE SYSTEM TO RECURVE AHEAD OF THE TROUGH AND BEGIN EXTRA-
TROPICAL TRANSITION (ET). THE SYSTEM IS EXPECTED TO GRADUALLY
INTENSIFY AS THE UPPER LEVEL ENVIRONMENT AND SEA SURFACE
TEMPERATURES REMAIN FAVORABLE THROUGH THE FIRST 48 TO 72 HOURS OF
THE FORECAST. TC 01S IS FORECAST TO COMPLETE ET BY TAU 96.
NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE TIMING OF
RECURVATURE AND OVERALL FORECAST TRACK, THEREFORE THIS FORECAST
REMAINS CLOSE TO MODEL CONSENSUS. THIS WARNING SUPERSEDES AND
CANCELS REF A, NAVMARFCSTCEN 042021Z DEC 11 TROPICAL CYCLONE
FORMATION ALERT (WTXS22 PGTW 042030) MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 050000Z IS 12 FEET. NEXT WARNINGS AT 051500Z AND 060300Z.//
=========================================================================
WTXS31 PGTW 20111205 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ONE) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 01S (ONE) WARNING NR 002
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
050600Z --- NEAR 12.1S 87.2E
MOVEMENT PAST SIX HOURS - 285 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
REPEAT POSIT: 12.1S 87.2E
---
FORECASTS:
12 HRS, VALID AT:
051800Z --- 12.4S 86.5E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT
125 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
125 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 160 DEG/ 03 KTS
---
24 HRS, VALID AT:
060600Z --- 12.9S 86.7E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
130 NM SOUTHEAST QUADRANT
115 NM SOUTHWEST QUADRANT
130 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 125 DEG/ 06 KTS
---
36 HRS, VALID AT:
061800Z --- 13.6S 87.8E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
135 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 120 DEG/ 12 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
070600Z --- 14.8S 89.9E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
135 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 115 DEG/ 15 KTS
---
72 HRS, VALID AT:
080600Z --- 17.4S 95.3E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
125 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 120 DEG/ 11 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
090600Z --- 19.8S 99.4E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
---
REMARKS:
050900Z POSITION NEAR 12.2S 87.0E.
TROPICAL CYCLONE (TC) 01S, LOCATED APPROXIMATELY 545 NM WEST OF THE
COCOS ISLANDS, HAS TRACKED WESTWARD AT 07 KNOTS OVER THE PAST SIX
HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS A RAPIDLY
CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CENTRAL
CONVECTION. A 050238Z SSMIS 37 GHZ MICROWAVE PASS SHOWS A FORMATIVE
MICROWAVE EYE AND TIGHTLY CURVED BANDING WRAPPING INTO THE LLCC. A
050013Z WINDSAT IMAGE SHOWS 50-55 KNOT WINDS NEAR THE LLCC. THE
CURRENT POSITION IS BASED ON THE AFOREMENTIONED MICROWAVE IMAGE AND
THE 050530Z KNES SATELLITE FIX WITH GOOD CONFIDENCE. THE CURRENT
INTENSITY IS BASED ON THE SCATTEROMETRY DATA IN CONJUNCTION WITH THE
EVIDENT MICROWAVE EYE. FURTHER ANALYSIS OF MICROWAVE DATA DURING THE
PAST 12 HOURS CONFIRMS THAT TC 01S HAS UNDERGONE RAPID
INTENSIFICATION. UPPER LEVEL ANALYSIS INDICATES THAT TC 01S IS
LOCATED UNDER THE RIDGE AXIS IN A REGION OF STRONG DIFFLUENT FLOW
ALOFT AND LOW VERTICAL WIND SHEAR. ANIMATED WATER VAPOR IMAGERY
SHOWS GOOD OUTFLOW IN THE WESTERN AND SOUTHERN SEMI-CIRCLES, BUT
OUTFLOW ALONG THE EASTERN PERIPHERY IS SOMEWHAT INHIBITED BY
EASTERLY FLOW ALOFT. THE SYSTEM IS CURRENTLY TRACKING ALONG THE
NORTHWESTERN PERIPHERY OF A FINGER OF THE SUBTROPICAL RIDGE
EXTENDING FROM SOUTH OF JAKARTA INDONESIA. TC 01S IS EXPECTED TO
CONTINUE TRACKING GENERALLY WESTWARD FOR THE NEXT 12 HOURS
BEFORE AN APPROACHING MID-LATITUDE TROUGH WEAKENS THE RIDGE AND
ALLOWS THE SYSTEM TO RECURVE AHEAD OF THE TROUGH AND BEGIN EXTRA-
TROPICAL TRANSITION (ET). THE SYSTEM IS EXPECTED TO GRADUALLY
INTENSIFY AS THE UPPER LEVEL ENVIRONMENT AND SEA SURFACE
TEMPERATURES REMAIN FAVORABLE THROUGH THE FIRST 48 TO 72 HOURS OF
THE FORECAST. TC 01S IS FORECAST TO BEGIN ET BY TAU 48 AND COMPLETE
ET BY TAU 96. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE
TIMING OF RECURVATURE AND OVERALL FORECAST TRACK. THEREFORE, THIS
FORECAST REMAINS CLOSE TO MODEL CONSENSUS THROUGH TAU 24. HOWEVER,
TRACK SPEEDS ARE SLIGHTLY FASTER THAN THE CONSENSUS TO CAPTURE THE
ACCELERATED ET TRANSITION THAT SHOULD OCCUR FROM THE DEEP MID-
LATITUDE TROUGH. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 050600Z IS 14
FEET. NEXT WARNINGS AT 052100Z AND 060900Z.//
=========================================================================
WTXS31 PGTW 20111205 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 003
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
051800Z --- NEAR 12.4S 87.2E
MOVEMENT PAST SIX HOURS - 250 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
REPEAT POSIT: 12.4S 87.2E
---
FORECASTS:
12 HRS, VALID AT:
060600Z --- 12.8S 87.0E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT
125 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
125 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 145 DEG/ 04 KTS
---
24 HRS, VALID AT:
061800Z --- 13.4S 87.4E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
130 NM SOUTHEAST QUADRANT
115 NM SOUTHWEST QUADRANT
130 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 120 DEG/ 14 KTS
---
36 HRS, VALID AT:
070600Z --- 14.8S 89.9E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
135 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 120 DEG/ 15 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
071800Z --- 16.3S 92.6E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
135 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 120 DEG/ 15 KTS
---
72 HRS, VALID AT:
081800Z --- 19.4S 98.1E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
125 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 125 DEG/ 16 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
091800Z --- 22.8S 103.7E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
---
REMARKS:
052100Z POSITION NEAR 12.5S 87.2E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 570 NM WEST
OF THE COCOS ISLANDS, HAS TRACKED WEST-SOUTHWESTWARD AT 03 KNOTS OVER
THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS WELL
DEVELOPED CONVECTIVE BANDING AROUND A SYMMETRICAL LOW LEVEL CIRCULA-
TION CENTER. A 051522Z ASCAT PASS SUPPORTS THE STRUCTURE AND CURRENT
INTENSITY OF THE LLCC WITH 35 TO 40 KNOT WINDS NOTED IN PASS. UPPER
LEVEL ANALYSIS SHOWS TC 01S HAS MOVED CLOSER TO THE SUBTROPICAL
RIDGE AXIS BUT IS STILL EQUATORWARD OF THE AXIS. A MID-LATITUDE SUB-
TROPICAL TROUGH SOUTH OF TC 01S HAS STARTED TO MODIFY THE POLEWARD
OUTFLOW CHANNEL, BUT THIS HAS NOT YET ALLOWED FOR ANY IMPROVEMENT AS
OUTFLOW HAS NOT IMPROVED OVER THE PAST 12 HOURS. THE TROUGH HAS ALSO
WEAKENED THE STEERING RIDGE CAUSING THE RECENT DECREASE IN TRACK
SPEED AND AS THE TROUGH BREAKS DOWN THE RIDGE FURTHER OVER THE NEXT
12 TO 24 HOURS, TC 01S WILL RECURVE TO THE EAST-SOUTHEAST. EXTRA-
TROPICAL TRANSITION (ET) WILL BEGIN AROUND TAU 48 AS TC 01S PRO-
GRESSES FURTHER TO THE EAST-SOUTHEAST INTO THE MID-LATITUDE FLOW.
COMPLETE CAPTURE BY THE MID-LATITUDE FLOW SHOULD OCCUR AROUND TAU 72
WITH TC 01S FINISHING THE ET PROCESS BY TAU 96. MODEL GUIDANCE IS IN
GOOD AGREEMENT WITH THIS SCENARIO, HOWEVER THE MAJORITY OF MODEL
GUIDANCE APPEARS TO LOSE TC 01S AFTER TAU 48, SLOWING THE SYSTEM
DOWN BEYOND. THE CURRENT FORECAST MAINTAINS TRACK SPEED BEYOND TAU
48, REMAINING CONSISTENT WITH THE ET PROCESS AND SLIGHTLY FASTER
THAN CONCENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051800Z IS 14
FEET. NEXT WARNINGS AT 060900Z AND 062100Z.//
=========================================================================
WTXS31 PGTW 20111206 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 004
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
060600Z --- NEAR 12.7S 87.3E
MOVEMENT PAST SIX HOURS - 205 DEGREES AT 02 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
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
REPEAT POSIT: 12.7S 87.3E
---
FORECASTS:
12 HRS, VALID AT:
061800Z --- 13.2S 88.1E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT
125 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
125 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 115 DEG/ 09 KTS
---
24 HRS, VALID AT:
070600Z --- 14.0S 89.7E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
130 NM SOUTHEAST QUADRANT
115 NM SOUTHWEST QUADRANT
130 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 120 DEG/ 14 KTS
---
36 HRS, VALID AT:
071800Z --- 15.3S 92.2E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
135 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 115 DEG/ 15 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
080600Z --- 16.6S 95.0E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
135 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 125 DEG/ 12 KTS
---
72 HRS, VALID AT:
090600Z --- 19.2S 99.3E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
125 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 145 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
100600Z --- 20.9S 100.7E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 175 DEG/ 03 KTS
---
120 HRS, VALID AT:
110600Z --- 21.9S 100.8E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
060900Z POSITION NEAR 12.8S 87.5E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 560 NM WEST
OF THE COCOS ISLANDS, HAS TRACKED SOUTH-SOUTHWESTWARD AT 02 KNOTS
OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS
A MARKED DECREASE IN CONVECTIVE ORGANIZATION OVER THE PAST 12 HOURS
WITH WEAKENING CONVECTIVE BANDING. A 060730Z AMSU IMAGE SHOWS
FRAGMENTED DEEP CONVECTIVE BANDING. THE CURRENT INTENSITY IS
ASSESSED AT 45 KNOTS BASED ON DVORAK INTENSITY ESTIMATES OF 45 KNOTS
FROM ALL AGENCIES. THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION
BASED ON A 060409Z METOP-A IMAGE AS WELL AS THE AFOREMENTIONED
060730Z AMSU IMAGE. TC 01S IS TRACKING SLOWLY ALONG THE WESTERN
PERIPHERY OF A WEAK NEAR-EQUATORIAL RIDGE BUT IS FORECAST TO TURN
EAST-SOUTHEASTWARD TO SOUTHEASTWARD AND ACCELERATE AHEAD OF A DEEP
SHORTWAVE TROUGH. MODEL GUIDANCE SUPPORTS THIS TRACK AND IS TIGHTLY
CLUSTERED THROUGH TAU 72. AFTER TAU 72, TC 01S IS EXPECTED TO SLOW,
WEAKEN AND THEN TURN SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF
THE LOW-LEVEL SUBTROPICAL RIDGE. MODEL GUIDANCE SUPPORTS THIS
SCENARIO WITH THE EXCEPTION OF GFDN. TC 01S IS EXPECTED TO INTENSIFY
UNDER A FAVORABLE ENVIRONMENT THROUGH TAU 36 BUT SHOULD BEGIN TO
WEAKEN BY TAU 48 AS IT BEGINS EXTRA-TROPICAL TRANSITION (ETT) AND
INTERACTS WITH THE UPPER-LEVEL TROUGH. THE SYSTEM IS NOT EXPECTED TO
COMPLETE ETT DUE TO AN INCREASINGLY HOSTILE ENVIRONMENT AND IS NOW
FORECAST TO DISSIPATE BY TAU 120. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
060600Z IS 20 FEET. NEXT WARNINGS AT 062100Z AND 070900Z.//
=========================================================================
WTXS31 PGTW 20111206 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 005
02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
061800Z --- NEAR 13.5S 87.9E
MOVEMENT PAST SIX HOURS - 125 DEGREES AT 04 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
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.5S 87.9E
---
FORECASTS:
12 HRS, VALID AT:
070600Z --- 14.3S 89.5E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 115 DEG/ 12 KTS
---
24 HRS, VALID AT:
071800Z --- 15.3S 91.8E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 110 DEG/ 13 KTS
---
36 HRS, VALID AT:
080600Z --- 16.3S 94.4E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
125 NM SOUTHEAST QUADRANT
125 NM SOUTHWEST QUADRANT
140 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 120 DEG/ 14 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
081800Z --- 17.7S 97.0E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
130 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 125 DEG/ 08 KTS
---
72 HRS, VALID AT:
091800Z --- 19.5S 99.6E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 145 DEG/ 06 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
101800Z --- 21.3S 101.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 170 DEG/ 05 KTS
---
120 HRS, VALID AT:
111800Z --- 23.3S 101.3E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
062100Z POSITION NEAR 13.7S 88.3E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 535 NM WEST
OF THE COCOS ISLANDS, HAS TRACKED SOUTHEASTWARD AT 04 KNOTS OVER THE
PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS CONVEC-
TION HAS STARTED TO BUILD WITH IMPROVING ORGANIZATION OVER THE LOW
LEVEL CIRCULATION CENTER (LLCC) DURING THE PAST 12 HOURS. A 061149Z
AND A 061503Z SSMIS IMAGE BOTH INDICATE THE DEEP CONVECTION AROUND
THE LLCC AND THE 1149Z IMAGE ALSO PROVIDED A POSITION FOR THE LLCC
WITH GOOD CONFIDENCE. UPPER LEVEL ANALYSIS INDICATES THAT A MID-
LATITUDE TROUGH HAS STARTED TO IMPINGE ON THE SOUTHWESTERN PORTION
OF TC 01S WHICH HAS ALSO BRIEFLY IMPROVED EASTERN OUTFLOW, LIKELY
RESPONSIBLE FOR THE RECENT IMPROVEMENTS IN CONVECTIVE STRUCTURE NOTED
EARLIER. TC 01S CONTINUES TO TRACK SLOWLY AROUND THE SOUTHWESTERN
PERIPHERY OF A WEAK NEAR-EQUATORIAL RIDGE AND IS EXPECTED TO INCREASE
IN TRACK SPEED OVER THE NEXT 24 HOURS AS IT BEGINS TO LINK TO A DEEP
MID-LATITUDE SHORTWAVE TROUGH. THE INTENSITY IS EXPECTED TO IMPROVE
THROUGH TAU 24 DUE TO THE INCREASED OUTFLOW BUT WILL THEN DECREASE
AS THE OVERALL ENVIRONMENT BECOMES UNFAVORABLE AROUND TAU 48. EXTRA
TROPICAL TRANSITION (ETT) WILL BEGIN AROUND TAU 48, HOWEVER, AS
TC 01S MOVES INTO AN INCREASINGLY HOSTILE ENVIRONMENT, ETT WILL
BE OVERTAKEN BY DISSIPATION, PREVENTING THE ETT PROCESS FROM
COMPLETING. THIS SCENARIO IS CONSISTENT WITH MODEL GUIDANCE. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 061800Z IS 20 FEET. NEXT WARNINGS AT
070900Z AND 072100Z. REFER TO TROPICAL CYCLONE 02S (TWO) WARNINGS
(WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES.//
=========================================================================
WTXS31 PGTW 20111207 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 006//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 006
02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
070600Z --- NEAR 14.5S 90.2E
MOVEMENT PAST SIX HOURS - 115 DEGREES AT 15 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.5S 90.2E
---
FORECASTS:
12 HRS, VALID AT:
071800Z --- 15.5S 92.6E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 120 DEG/ 14 KTS
---
24 HRS, VALID AT:
080600Z --- 16.8S 95.1E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 120 DEG/ 13 KTS
---
36 HRS, VALID AT:
081800Z --- 18.0S 97.4E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 130 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
090600Z --- 19.2S 99.0E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 140 DEG/ 04 KTS
---
72 HRS, VALID AT:
100600Z --- 20.6S 100.2E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 165 DEG/ 03 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
110600Z --- 21.7S 100.5E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 180 DEG/ 01 KTS
---
120 HRS, VALID AT:
120600Z --- 22.2S 100.5E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
070900Z POSITION NEAR 14.8S 90.8E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 415 NM
WEST-SOUTHWEST OF THE COCOS ISLANDS, HAS TRACKED EAST-SOUTHEASTWARD
AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) SHOWS IMPROVED DEEP CONVECTIVE BANDING
WRAPPING INTO A WELL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC). A
070214Z SSMIS MICROWAVE IMAGE ALSO DEPICTS A TIGHTLY CURVED DEEP
CONVECTIVE BAND WRAPPING AROUND THE NORTHERN PERIPHERY OF THE LLCC.
THE INITIAL POSITION IS BASED WITH FAIR CONFIDENCE ON THE MSI. THE
INITIAL INTENSITY IS BASED ON THE PGTW AND KNES DVORAK ESTIMATES OF
55 KNOTS. OUTFLOW TO THE SOUTHEAST HAS IMPROVED INTO AN UPPER LEVEL
LOW, HOWEVER OUTFLOW TO THE SOUTHWEST IS INHIBITED BY AN UPPER LEVEL
TROUGH. EQUATORWARD OUTFLOW REMAINS FAVORABLE. TC 01S IS CURRENTLY
TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL SUBTROPICAL
STEERING RIDGE AND IS EXPECTED TO CONTINUE TRACKING GENERALLY EAST-
SOUTHEASTWARD THROUGHOUT THE FORECAST PERIOD. TC 01S IS FORECAST TO
CONTINUE TO INTENSIFY DUE TO FAVORABLE OUTFLOW ALOFT AND WARM SEA
SURFACE TEMPERATURES. BY TAU 72, THE SYSTEM WILL BEGIN TO RAPIDLY
WEAKEN AS VERTICAL WIND SHEAR ASSOCIATED WITH THE MID-LATITUDE
WESTERLIES INCREASES. TC 01S IS EXPECTED TO DISSIPATE AS A
SIGNIFICANT TROPICAL CYCLONE BY TAU 120, BEFORE COMPLETING EXTRA-
TROPICAL TRANSITION. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT.
THEREFORE, THIS FORECAST IS IN GOOD AGREEMENT WITH MODEL CONSENSUS.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070600Z IS 20 FEET. NEXT WARNINGS
AT 072100Z AND 080900Z. REFER TO TROPICAL CYCLONE 02S (TWO) WARNINGS
(WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES.//
=========================================================================
WTXS31 PGTW 20111207 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 007//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 007
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
071800Z --- NEAR 15.3S 93.0E
MOVEMENT PAST SIX HOURS - 110 DEGREES AT 14 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
REPEAT POSIT: 15.3S 93.0E
---
FORECASTS:
12 HRS, VALID AT:
080600Z --- 16.7S 95.6E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 125 DEG/ 14 KTS
---
24 HRS, VALID AT:
081800Z --- 18.2S 98.0E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 125 DEG/ 12 KTS
---
36 HRS, VALID AT:
090600Z --- 19.6S 100.0E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 140 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
091800Z --- 21.1S 101.4E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 155 DEG/ 05 KTS
---
72 HRS, VALID AT:
101800Z --- 22.9S 102.3E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 150 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
111800Z --- 24.5S 103.4E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
072100Z POSITION NEAR 15.7S 93.6E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 295 NM
SOUTHWEST OF THE COCOS ISLANDS, HAS TRACKED EAST-SOUTHEASTWARD AT 15
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED IMAGERY SHOWS RECENT
IMPROVEMENT IN ORGANIZATION OF THE LOW LEVEL CIRCULATION CENTER
WITH A VISIBLE EYE FEATURE PRESENT. BASED ON DVORAK FIXES FROM PGTW
AND KNES THE INTENSITY FOR TC 01S HAS BEEN INCREASED TO 65 KNOTS.
TC 01S CONTINUES TO BE STEERED UNDER THE INFLUENCE OF A NEAR
EQUATORIAL RIDGE TO THE NORTHEAST AND A MID-LATITUDE TROUGH TO THE
SOUTHWEST. UPPER LEVEL ANALYSIS INDICATES THAT DRY MID-LATITUDE AIR
HAS STARTED TO IMPINGE ON THE WESTERN SEMI-CIRCLE AND IS WRAPPING
AROUND THE NORTHERN PERIPHERY OF THE SYSTEM. ADDITIONALLY, INCREASING
LEVELS OF VERTICAL WIND SHEAR ON THE WESTERN SIDE OF TC 01S HAS
BEGUN TO HAMPER EQUATORWARD OUTFLOW. THE SYSTEM WILL CONTINUE TO
TRACK AHEAD OF THE MID-LATITUDE TROUGH AROUND THE SOUTHWESTERN PERI-
PHERY OF A NEAR EQUATORIAL RIDGE. DECREASING SEA SURFACE TEMPERA-
TURES, INCREASING VERTICAL WIND SHEAR AND THE INTRUSION OF DRY AIR
FROM THE WEST WILL BEGIN TO WEAKEN THE SYSTEM BETWEEN TAU 12 AND
TAU 24. DISSIPATION WILL BEGIN AROUND TAU 48 WITH FULL DISSI-
PATION BY TAU 96. MODEL GUIDANCE INDICATES THE TRACK WILL REMAIN
CONSISTENT THROUGH TAU 36 BUT WILL TURN MORE SOUTHEASTWARD AS THE
STEERING INFLUENCES SHIFT TO LOWER LEVELS. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 071800Z IS 16 FEET. NEXT WARNINGS AT 080900Z AND 082100Z.//
=========================================================================
WTXS31 PGTW 20111208 03:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 008//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 008
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
080000Z --- NEAR 16.3S 94.8E
MOVEMENT PAST SIX HOURS - 120 DEGREES AT 20 KTS
POSITION ACCURATE TO WITHIN 025 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
REPEAT POSIT: 16.3S 94.8E
---
FORECASTS:
12 HRS, VALID AT:
081200Z --- 17.8S 97.4E
MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 115 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
115 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 130 DEG/ 14 KTS
---
24 HRS, VALID AT:
090000Z --- 19.6S 99.8E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 130 DEG/ 13 KTS
---
36 HRS, VALID AT:
091200Z --- 21.3S 101.9E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 130 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
100000Z --- 22.2S 103.0E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 140 DEG/ 05 KTS
---
72 HRS, VALID AT:
110000Z --- 23.7S 104.3E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 96 HR POSIT: 135 DEG/ 04 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
120000Z --- 24.7S 105.5E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
080300Z POSITION NEAR 16.7S 95.4E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 285 NM
SOUTH-SOUTHWEST OF THE COCOS ISLANDS, HAS TRACKED EAST-SOUTHEASTWARD
AT 20 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED INFRARED AND
VISIBLE SATELLITE IMAGERY INDICATE THAT TC 01S HAS INTENSIFIED MORE
RAPIDLY THAN PREVIOUSLY FORECAST. VISIBLE IMAGERY DEPICTS A SMALL
250 NM DIAMETER SYSTEM WITH A SYMMETRIC 15 NM EYE. A 072319Z
CORIOLIS MICROWAVE PASS REVEALS A WELL DEFINED MICROWAVE EYE WITH
SPIRAL BANDING WRAPPING TIGHTLY INTO THE SYSTEM FROM ALL QUADRANTS.
THE CURRENT POSITION IS BASED ON THE MICROWAVE EYE IN THE CORIOLIS
PASS WITH HIGH CONFIDENCE. THE CURRENT INTENSITY IS BASED ON DVORAK
ESTIMATES FROM PGTW, APRF, AND KNES RANGING FROM 77 TO 102 KNOTS.
UPPER LEVEL ANALYSIS INDICATES THAT WHILE TC 01S IS EXPERIENCING
MODERATE DRY AIR IMPINGEMENT ALONG ITS WESTERN PERIPHERY, LOW
VERTICAL WIND SHEAR, STRONG DIFFLUENT FLOW ALOFT, AND EXCELLENT DUAL
CHANNEL OUTFLOW HAVE ALLOWED THE SYSTEM TO RAPIDLY INTENSIFY OVER
THE PAST 12 HOURS. TC 01S IS CURRENTLY TRACKING ALONG THE
SOUTHWESTERN PERIPHERY OF A NEAR EQUATORIAL RIDGE AND IS EXPECTED TO
CONTINUE TRACKING GENERALLY SOUTHEASTWARD AHEAD OF A DEEP MID-
LATITUDE TROUGH THROUGHOUT THE FORECAST PERIOD. TC 01S HAS ALREADY
BEGUN TO ACCELERATE AND SHOULD BEGIN EXTRA-TROPICAL TRANSITION
WITHIN THE NEXT 24 HOURS. HOWEVER, INCREASING VERTICAL WIND SHEAR,
DECREASING SEA SURFACE TEMPERATURES, AND FURTHER DRY AIR INTRUSION
WILL BEGIN TO WEAKEN THE SYSTEM AS IT APPROACHES 20 DEGREES SOUTH,
CAUSING THE SYSTEM TO DISSIPATE BEFORE COMPLETING EXTRA-TROPICAL
TRANSITION. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE
OVERALL TRACK FORECAST; HOWEVER THERE IS SOME DISPARITY IN THE
TIMING OF DISSIPATION BETWEEN THE MODELS. THIS FORECAST REMAINS
CLOSE TO MODEL CONSENSUS, BUT SLIGHTLY SLOWER IN THE LATER TAUS IN
FAVOR OF ECMWF, EGRR, AND JGSM WHICH INDICATE DISSIPATION SHORTLY
AFTER THE SYSTEM CROSSES 22 DEGREES SOUTH. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 080000Z IS 20 FEET. NEXT WARNINGS AT 081500Z AND 090300Z.//
=========================================================================
WTXS31 PGTW 20111208 15:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 009//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 009
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
081200Z --- NEAR 18.4S 98.9E
MOVEMENT PAST SIX HOURS - 115 DEGREES AT 22 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
REPEAT POSIT: 18.4S 98.9E
---
FORECASTS:
12 HRS, VALID AT:
090000Z --- 20.4S 101.7E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 125 DEG/ 13 KTS
---
24 HRS, VALID AT:
091200Z --- 21.8S 104.0E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 125 DEG/ 11 KTS
---
36 HRS, VALID AT:
100000Z --- 23.0S 106.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 48 HR POSIT: 130 DEG/ 06 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
101200Z --- 23.8S 107.1E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 72 HR POSIT: 125 DEG/ 05 KTS
---
72 HRS, VALID AT:
111200Z --- 24.9S 108.8E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
081500Z POSITION NEAR 18.9S 99.6E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 400 NM
SOUTH-SOUTHEAST OF THE COCOS ISLANDS, HAS TRACKED EAST-SOUTHEASTWARD
AT 22 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL
SATELLITE IMAGERY SHOWS THAT TC 01S HAS LOST IT'S SMALL EYE FEATURE
AS A COLD AIR STRATOCUMULUS FIELD TO THE WEST BEGINS TO ADVECT INTO
THE LOW LEVEL CIRCULATION CENTER (LLCC). A 081122Z SSMIS 91 GHZ
IMAGE INDICATES THAT THE MID- TO UPPER-LEVEL DEEP CONVECTION IS
BEGINNING TO ELONGATE TO THE SOUTHEAST AS TC 01S INTERACTS WITH A
DEEP MID-LATITUDE TROUGH. THE 37 GHZ IMAGE ALONG WITH TOTAL
PRECIPITABLE WATER ANIMATION REVEALS THAT MODERATE DRY AIR
ENTRAINMENT ON THE WESTERN SIDE OF THE LLCC HAS BEGUN TO ERODE THE
LOW-LEVEL BANDING. THE INITIAL POSITION IS BASED ON THE SSMIS IMAGE
ALONG WITH AGREEABLE 081130Z PGTW AND KNES POSITION FIXES. THE
INITIAL INTENSITY IS BASED ON DVORAK ESTIMATES FROM PGTW AND KNES
INDICATING 77 KNOTS. UPPER LEVEL ANALYSIS INDICATES THAT TC 01S LIES
APPROXIMATELY 07 DEGREES SOUTH OF THE NEAR EQUATORIAL RIDGE AXIS IN
AN AREA OF LOW (10-15 KNOT) VERTICAL WIND SHEAR WITH STRONG
DIFFLUENT FLOW ALOFT. RECENT ANIMATED WATER VAPOR IMAGERY CONTINUES
TO SHOW EXCELLENT DUAL CHANNEL OUTFLOW. TC 01S IS CURRENTLY TRACKING
ALONG THE SOUTHWESTERN PERIPHERY OF A NEAR EQUATORIAL RIDGE AND IS
EXPECTED TO CONTINUE TRACKING GENERALLY SOUTHEASTWARD AHEAD OF A
DEEP MID-LATITUDE TROUGH THROUGHOUT THE FORECAST PERIOD. TC 01S
CONTINUES TO ACCELERATE AND SHOULD BEGIN EXTRA-TROPICAL TRANSITION
WITHIN THE NEXT 12 HOURS. HOWEVER, INCREASING VERTICAL WIND SHEAR,
DECREASING SEA SURFACE TEMPERATURES, AND FURTHER DRY AIR INTRUSION
WILL BEGIN TO WEAKEN THE SYSTEM AS IT APPROACHES 20 DEGREES SOUTH,
CAUSING THE SYSTEM TO DISSIPATE BEFORE COMPLETING EXTRA-TROPICAL
TRANSITION. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE
OVERALL TRACK FORECAST; HOWEVER THERE IS SOME DISPARITY IN THE
TIMING OF DISSIPATION BETWEEN THE MODELS. THIS FORECAST REMAINS
CLOSE TO MODEL CONSENSUS BUT SLIGHTLY FASTER DURING TAUS 24-36 TO
OFFSET THE EXTREME EARLY DISAPATION PORTRAYED BY ECMWF AND JGSM.
ADDITIONALLY, THIS FORECAST IS SLIGHTLY SLOWER DURING TAU 72 TO
OFFSET THE NOGAPS/GFDN/GFS/WBAR TRACKERS THAT TAKE THE SYSTEM OVER
WESTERN AUSTRALIA. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 081200Z IS 20
FEET. NEXT WARNINGS AT 090300Z AND 091500Z.//
=========================================================================
WTXS31 PGTW 20111209 03:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 010//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 010
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
090000Z --- NEAR 20.7S 101.7E
MOVEMENT PAST SIX HOURS - 135 DEGREES AT 16 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
REPEAT POSIT: 20.7S 101.7E
---
FORECASTS:
12 HRS, VALID AT:
091200Z --- 22.1S 103.7E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 125 DEG/ 10 KTS
---
24 HRS, VALID AT:
100000Z --- 23.2S 105.4E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
090300Z POSITION NEAR 21.0S 102.2E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 700 NM
WEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT 16 KNOTS
OVER THE PAST SIX HOURS. RECENT ANIMATED INFRARED AND VISIBLE
SATELLITE IMAGERY, ALONG WITH A 082235Z SSMIS MICROWAVE PASS, REVEAL
A PARTIALLY EXPOSED AND ELONGATED LOW LEVEL CIRCULATION CENTER
(LLCC) WITH CONVECTION BEING SHEARED TO THE SOUTHEAST AND WEAKENING.
THE CURRENT POSITION IS BASED ON THE AFOREMENTIONED MICROWAVE IMAGE
AND THE PARTIALLY EXPOSED LLCC IN VISIBLE IMAGERY WITH FAIR
CONFIDENCE. THE CURRENT INTENSITY IS BASED ON DVORAK ESTIMATES FROM
KNES, ABRF, AND PGTW RANGING FROM 35 TO 55 KNOTS. ENVIRONMENTAL
ANALYSIS REVEALS THAT TC 01S HAS ENTERED A HOSTILE ENVIRONMENT WITH
HIGH (40+ KNOTS) NORTHWESTERLY VERTICAL WIND SHEAR (VWS),
UNFAVORABLE SEA SURFACE TEMPERATURES (< 26 DEGREES CELSIUS), AND
CONTINUED DRY AIR IMPINGEMENT ALONG THE WESTERN PERIPHERY. TC ALENGA
IS CURRENTLY TRACKING AHEAD OF A DEEP MID-LATITUDE TROUGH, ALONG THE
SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE ANCHORED OVER
NORTHERN AUSTRALIA. AS THE SYSTEM CONTINUES TRACKING SOUTHEASTWARD
OVER THE NEXT 24 HOURS, VWS WILL CONTINUE TO INCREASE AND CAUSE THE
SYSTEM TO SHEAR APART. REMNANTS OF THE LLCC WILL LIKELY SLOW AND
TRACK SLIGHTLY POLEWARD DUE TO THE LOW LEVEL FLOW. NUMERICAL MODEL
GUIDANCE IS IN GOOD AGREEMENT WITH THE OVERALL TRACK DIRECTION, BUT
THERE REMAINS A WIDE DISPARITY BETWEEN JGSM, EGRR, AND ECMWF WHICH
INDICATE SLOWER TRACK SPEEDS AND DISSIPATION; AND GFDN, NGPS, AND
GFS WHICH RAPIDLY CARRY THE SYSTEM INTO SOUTHWESTERN AUSTRALIA. THIS
FORECAST IS SLIGHTLY SLOWER AND POLEWARD OF CONSENSUS IN FAVOR OF A
RAPID DISSIPATION SCENARIO AND SLOW POLEWARD DRIFT OF THE TC
REMNANTS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 090000Z IS 17 FEET.
NEXT WARNINGS AT 091500Z.//
=========================================================================
WTXS31 PGTW 20111209 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 011//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 011
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
090600Z --- NEAR 21.4S 102.5E
MOVEMENT PAST SIX HOURS - 135 DEGREES AT 10 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
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
REPEAT POSIT: 21.4S 102.5E
---
FORECASTS:
12 HRS, VALID AT:
091800Z --- 22.3S 103.4E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
090900Z POSITION NEAR 21.6S 102.7E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 640 NM
WEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT 10 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS A FULLY EXPOSED AND DETERIORATING LOW LEVEL
CIRCULATION CENTER (LLCC) WITH CONVECTION SHEARED ALMOST 200 NM TO
THE SOUTHEAST. THE CURRENT POSITION IS BASED ON THE EXPOSED LLCC IN
MSI WITH HIGH CONFIDENCE. THE CURRENT INTENSITY IS BASED ON DVORAK
ESTIMATES FROM KNES OF 35 KNOTS AND FROM A 090311Z ASCAT PASS
SHOWING AN ELONGATED CIRCULATION WITH 25-30 KNOT WINDS AROUND THE
CENTER. TC 01S IS FORECAST TO DISSIPATE AS A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 12 HOURS AS IT SUCCUMBS TO HIGH VERTICAL
WIND SHEAR AND UNFAVORABLE SEA SURFACE TEMPERATURES. THIS IS THE
FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WARNING CENTER
(NAVMARFCSTCEN). THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF
REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 090600Z IS 15
FEET.//
Tropical cyclone tracks developed by Michael Bath using operational warnings and advisories.
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Document: tropical_cyclone_alenga_jtwc_advisories.htm
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