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Tropical Cyclone 201515 : JTWC Advisories
Season 2014-2015 Summaries (Operational Data): [AU] [SIO] [SPAC] [SH]
---> Tropical Cyclone 201515 Track Map and Data

WTXS21 PGTW 20150304 22:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
125 NM EITHER SIDE OF A LINE FROM 13.9S 41.7E TO 16.7S 43.1E
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
IMAGERY AT 041900Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 14.6S 42.1E. THE SYSTEM IS MOVING SOUTHWARD AT 03 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 14.3S
42.1E IS NOW LOCATED NEAR 14.6S 42.1E, APPROXIMATELY 385 NM
NORTHWEST OF ANTANANARIVO, MADAGASCAR. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION
CENTER (LLCC) WITH PERSISTENT CONVECTION SHEARED TO THE NORTHWEST. A
041921Z AMSU-B MICROWAVE IMAGE SHOWS A WELL-DEFINED LLCC WITH WEAK
FORMATIVE CONVECTIVE BANDING ALONG THE SOUTHERN PERIPHERY WRAPPING
TOWARDS THE LLCC. A 041923Z ASCAT IMAGE SHOWS A DEFINED CIRCULATION
WITH 25 TO 30 KNOT WINDS NEAR THE CENTER. UPPER LEVEL ANALYSIS
INDICATES THAT THE SYSTEM IS IN A MARGINALLY-FAVORABLE ENVIRONMENT
WITH MODERATE (20-25 KNOT) SOUTHEASTERLY VERTICAL WIND SHEAR (VWS)
PARTIALLY OFFSET BY EXCELLENT DUAL CHANNEL OUTFLOW. GLOBAL MODEL
GUIDANCE INDICATES A SOUTHEASTWARD TRACK INTO AN AREA OF LOWER VWS
(15-20 KNOT), LEADING TO GRADUAL INTENSIFICATION. SEA SURFACE
TEMPERATURES OF 29-30 DEGREES CELSIUS ARE ALSO CONDUCIVE FOR FURTHER
DEVELOPMENT. 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
052200Z.
=========================================================================
WTXS31 PGTW 20150305 15:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 001//
RMKS/
1. TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 001
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   051200Z --- NEAR 15.9S 42.1E
     MOVEMENT PAST SIX HOURS - 210 DEGREES AT 06 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
   REPEAT POSIT: 15.9S 42.1E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   060000Z --- 16.6S 42.1E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 24 HR POSIT: 235 DEG/ 03 KTS
    ---
   24 HRS, VALID AT:
   061200Z --- 17.0S 41.5E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 270 DEG/ 04 KTS
    ---
   36 HRS, VALID AT:
   070000Z --- 17.0S 40.7E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 315 DEG/ 02 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   071200Z --- 16.7S 40.4E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 090 DEG/ 02 KTS
    ---
   72 HRS, VALID AT:
   081200Z --- 16.7S 41.3E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 110 DEG/ 05 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   091200Z --- 17.3S 43.3E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 120 HR POSIT: 120 DEG/ 09 KTS
    ---
   120 HRS, VALID AT:
   101200Z --- 19.0S 46.8E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
051500Z POSITION NEAR 16.1S 42.1E.
TROPICAL CYCLONE (TC) 15S (FIFTEEN), LOCATED APPROXIMATELY 393 NM
NORTH-NORTHEAST OF EUROPA ISLAND, HAS TRACKED SOUTH-SOUTHWESTWARD
AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC) WITH ASSOCIATED PERSISTENT DEEP
CONVECTION, MOSTLY ON THE WESTERN SIDE OF THE SYSTEM. A 051009Z GCOM
36 GHZ IMAGE CLEARLY DEPICTS LOW LEVEL CONVECTIVE BANDING WRAPPING
INTO THE LLCC WITH THE 91 GHZ SHOWING THE DEEP CONVECTION TO THE
NORTHWEST. THE CURRENT POSITION IS BASED ON THE AFOREMENTIONED
IMAGERY AND ANIMATION WITH GOOD CONFIDENCE. UPPER LEVEL ANALYSIS
INDICATES A MARGINAL ENVIRONMENT WITH HIGH (30 TO 40 KNOTS) VERTICAL
WIND SHEAR OVER THE NORTHERN PORTION OF THE SYSTEM AND AVERAGE UPPER
LEVEL DIVERGENCE. WARM SEA SURFACE TEMPERATURES IN THE MOZAMBIQUE
CHANNEL, HOWEVER, ARE FAVORABLE FOR DEVELOPMENT. THE SYSTEM IS
CURRENTLY TRACKING ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) ANCHORED EAST OF MADAGASCAR. EXPECT THE SYSTEM TO SLOWLY
TRACK TO THE WEST AS A FINGER OF THE STR EXTENDS IN THROUGH CENTRAL
MADAGASCAR. BEYOND TAU 48, THE STR WILL RETREAT TO THE EAST,
ALLOWING THE SYSTEM TO TRACK IN THAT DIRECTION. SHORTLY AFTER TAU
96, EXPECT TC 15S TO IMPACT THE BEMARAHA PLATEAU BEFORE DISSIPATING
OVER THE MADAGASCAR RANGE DUE TO LAND INTERACTION. AN ALTERNATE
SCENARIO DOES NOT HAVE THE STR EXTEND THROUGH MADAGASCAR, ALLOWING
THE SYSTEM TO TRACK TO THE EAST BY TAU 36 AND INTO ISLAND NATION AS
EARLY AS TAU 48. DUE TO THE VERY LARGE SPREAD IN THE LIMITED MODEL
GUIDANCE, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST
TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051200Z IS 10 FEET. NEXT
WARNINGS AT 060300Z AND 061500Z.//
=========================================================================
WTXS31 PGTW 20150306 03:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 15S (FIFTEEN) 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:
   060000Z --- NEAR 16.6S 42.3E
     MOVEMENT PAST SIX HOURS - 165 DEGREES AT 04 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
   WIND RADII VALID OVER OPEN WATER ONLY
   REPEAT POSIT: 16.6S 42.3E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   061200Z --- 17.0S 42.0E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 24 HR POSIT: 270 DEG/ 02 KTS
    ---
   24 HRS, VALID AT:
   070000Z --- 17.0S 41.6E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 270 DEG/ 01 KTS
    ---
   36 HRS, VALID AT:
   071200Z --- 17.0S 41.4E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            045 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 135 DEG/ 01 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   080000Z --- 17.2S 41.6E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            055 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 125 DEG/ 04 KTS
    ---
   72 HRS, VALID AT:
   090000Z --- 18.2S 43.1E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
                            030 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            055 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 115 DEG/ 07 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   100000Z --- 19.4S 45.8E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 120 HR POSIT: 115 DEG/ 11 KTS
    ---
   120 HRS, VALID AT:
   110000Z --- 21.0S 50.0E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
060300Z POSITION NEAR 16.7S 42.2E.
TROPICAL CYCLONE (TC) 15S (FIFTEEN), LOCATED APPROXIMATELY 356 NM
NORTH-NORTHEAST OF EUROPA ISLAND, HAS TRACKED SOUTH-SOUTHEASTWARD
AT 04 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED
ON A 052254Z AMSU IMAGE AND FIXES FROM PGTW AND KNES. THE INTENSITY
OF 35 KNOTS IS CONSISTENT WITH RECENT SUBJECTIVE AND AUTOMATED DVORAK
ESTIMATES. MODERATE SOUTHEASTERLY VERTICAL WIND SHEAR CONTINUES TO
IMPACT THE SYSTEM, LEAVING THE LOW-LEVEL CIRCULATION CENTER (LLCC)
PARTIALLY EXPOSED AND CONFINING LIMITED DEEP CONVECTION TO THE
NORTHWESTERN PORTION OF THE CIRCULATION. TC 15S IS TRACKING SLOWLY
SOUTHWARD ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL STEERING RIDGE
TO THE EAST. OVER THE NEXT 12 TO 24 HOURS, THE SYSTEM WILL ENTER A
COMPETING STEERING ENVIRONMENT BETWEEN THE CURRENT STEERING RIDGE
AND A SECOND SUBTROPICAL RIDGE POSITIONED TO THE SOUTHWEST. THE
CYCLONE IS THEN EXPECTED TO REMAIN NEARLY QUASI-STATIONARY THROUGH
TAU 48 BEFORE ACCELERATING SOUTHEASTWARD ALONG THE PERIPHERY OF
A NEAR-EQUATORIAL RIDGE THAT WILL BUILD TO THE NORTH. PASSAGE OVER
VERY WARM WATER AND A SLOW DECREASE IN VERTICAL WIND SHEAR
ASSOCIATED WITH A REORIENTATION OF THE UPPER-LEVEL PATTERN WILL
SUPPORT SLOW INTENSIFICATION THROUGH TAU 72. THEREAFTER, THE SYSTEM
IS EXPECTED TO CROSS MADAGASCAR AND DISSIPATE DUE TO LAND
INTERACTION. AVAILABLE NUMERICAL MODEL GUIDANCE IS IN GOOD GENERALLY
AGREEMENT WITH A QUASI-STATIONARY TRACK IN THE NEAR TO MEDIUM TERM
FOLLOWED BY ACCELERATION TOWARD MADAGASCAR. HOWEVER, THERE IS BROAD
DISAGREEMENT REGARDING TIMING OF THE EVENTUAL TURN TOWARD
MADAGASCAR AND POST-TURN TRACK SPEEDS. GIVEN HIGH UNCERTAINTY IN
THIS SCENARIO, MOST MODEL SOLUTIONS APPEAR EQUALLY PLAUSIBLE.
THEREFORE, THE CURRENT FORECAST LIES CLOSE TO THE MULTI-MODEL
CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 060000Z IS 12 FEET.
NEXT WARNINGS AT 061500Z AND 070300Z.//
=========================================================================
WTXS31 PGTW 20150306 15:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 15S (FIFTEEN) 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:
   061200Z --- NEAR 16.5S 41.4E
     MOVEMENT PAST SIX HOURS - 300 DEGREES AT 02 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
   REPEAT POSIT: 16.5S 41.4E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   070000Z --- 16.5S 41.0E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 24 HR POSIT: 295 DEG/ 02 KTS
    ---
   24 HRS, VALID AT:
   071200Z --- 16.3S 40.6E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 100 DEG/ 02 KTS
    ---
   36 HRS, VALID AT:
   080000Z --- 16.4S 41.1E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            045 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 135 DEG/ 06 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   081200Z --- 17.2S 42.0E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            055 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 130 DEG/ 05 KTS
    ---
   72 HRS, VALID AT:
   091200Z --- 18.5S 43.6E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
                            030 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            055 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 110 DEG/ 09 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   101200Z --- 19.7S 47.0E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 120 HR POSIT: 095 DEG/ 13 KTS
    ---
   120 HRS, VALID AT:
   111200Z --- 20.2S 52.5E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
061500Z POSITION NEAR 16.5S 41.3E.
TROPICAL CYCLONE (TC) 15S (FIFTEEN), LOCATED APPROXIMATELY 349 NM
NORTH-NORTHEAST OF EUROPA ISLAND, HAS TRACKED WEST-NORTHWESTWARD AT
02 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON A
061130Z N-19 AMSU-B IMAGE AS WELL AS FIX LOCATIONS FROM ALL
AGENCIES. ADDITIONALLY, THE CURRENT INTENSITY OF 35 KNOTS IS
DEVELOPED FROM AN UNANIMOUS DVORAK INTENSITY ESTIMATE FROM ALL
REPORTING AGENCIES. IR IMAGERY CONFIRMS THAT THE DEEP CONVECTION
REMAINS SHEARED TO THE NORTHWEST OF THE OBSCURED LOW LEVEL
CIRCULATION CENTER. UPPER LEVEL ANALYSIS REINFORCES THAT THE
NORTHERN PORTION OF THE SYSTEM REMAINS TO BE UNDER THE INFLUENCE OF
HIGH (20 TO 35 KNOT) VERTICAL WIND SHEAR (VWS), CONTINUING TO HAMPER
SIGNIFICANT DEVELOPMENT. EXPECT TC 15S TO SLOWLY TRACK TO THE WEST
UNDER THE STEERING INFLUENCE OF A SUBTROPICAL RIDGE TO THE SOUTHWEST
OF THE SYSTEM THROUGH TAU 36. BEYOND THAT, EXPECT THE NEAR
EQUATORIAL RIDGE (NER) TO BUILD IN NORTH OF THE SYSTEM, TAKING OVER
AS THE MAIN STEERING INFLUENCE AND DRIVING THE SYSTEM TO THE EAST.
AT THIS POINT, THE VWS WILL SUBSIDE AND ALLOW THE SYSTEM TO
STRENGTHEN TO A PEAK INTENSITY OF 55 KNOTS BY TAU 72. IN THE
EXTENDED FORECAST, TC 15S WILL IMPACT CENTRAL MADAGASCAR AND WEAKEN
DUE TO LAND INTERACTION. DUE TO ITS STRENGTH UPON IMPACT WITH THE
ISLAND NATION, THERE REMAINS THE POSSIBILITY THAT THE REMNANTS OF TC
15S WILL RE-EMERGE IN THE SOUTHERN INDIAN OCEAN BELOW WARNING
CRITERIA WITH A VERY UNLIKELY CHANCE OF RE-INTENSIFICATION. WHILE
DYNAMIC MODEL GUIDANCE IS IN BETTER AGREEMENT THAN PREVIOUS RUNS,
THERE REMAINS TO BE DISAGREEMENT IN WHEN THE SYSTEM WILL TRACK TO
THE EAST. AS SUCH, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC
FORECAST TRACK, WHICH IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 061200Z IS 14 FEET. NEXT WARNINGS
AT 070300Z AND 071500Z.//
=========================================================================
WTXS31 PGTW 20150306 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 15S (FIFTEEN) 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:
   061800Z --- NEAR 16.8S 41.3E
     MOVEMENT PAST SIX HOURS - 270 DEGREES AT 03 KTS
     POSITION ACCURATE TO WITHIN 030 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
   REPEAT POSIT: 16.8S 41.3E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   070600Z --- 16.8S 41.1E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 24 HR POSIT: 335 DEG/ 01 KTS
    ---
   24 HRS, VALID AT:
   071800Z --- 16.6S 41.0E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 060 DEG/ 01 KTS
    ---
   36 HRS, VALID AT:
   080600Z --- 16.5S 41.2E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            045 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 130 DEG/ 10 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   081800Z --- 17.7S 42.8E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
                            055 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            055 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 120 DEG/ 06 KTS
    ---
   72 HRS, VALID AT:
   091800Z --- 18.9S 44.9E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 96 HR POSIT: 110 DEG/ 06 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   101800Z --- 19.7S 47.3E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
062100Z POSITION NEAR 16.8S 41.2E.
TROPICAL CYCLONE (TC) 15S (FIFTEEN), LOCATED APPROXIMATELY 330 NM OF
EUROPA ISLAND, HAS TRACKED WESTWARD AT 03 KNOTS OVER THE PAST SIX
HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS AN AREA OF
FLARING CONVECTION ALONG THE WESTERN QUADRANT OF A PARTIALLY EXPOSED
LOW LEVEL CIRCULATION CENTER (LLCC). A 061540Z SSMIS MICROWAVE IMAGE
CONTINUES TO SHOW A WELL-DEFINED LLCC WITH LIMITED CONVECTION
SHEARED TO THE WEST. UPPER LEVEL ANALYSIS INDICATES THAT TC 15S IS
LOCATED NORTH OF THE SUB-TROPICAL RIDGE (STR) IN AN AREA OF STRAIGHT
LINE EASTERLY FLOW CREATING MODERATE TO HIGH (20 TO 30 KNOTS)
VERTICAL WIND SHEAR (VWS) WHICH IS BEING PARTIALLY OFFSET BY GOOD
EQUATORWARD OUTFLOW. THE CURRENT POSITION IS BASED ON THE
AFOREMENTIONED MICROWAVE IMAGERY WITH GOOD CONFIDENCE. THE CURRENT
INTENSITY OF 35 KNOTS IS BASED ON A 061841Z ASCAT PASS DISPLAYING 30
TO 35 KNOT WINDS AND CONCURRING DVORAK INTENSITY ESTIMATES FROM ALL
AGENCIES. TC 15S IS SLOWLY TRACKING WESTWARD UNDER THE INFLUENCE OF
A STR TO THE WEST; HOWEVER, THERE IS A COMPETING STEERING
ENVIRONMENT WHICH WILL CAUSE THE SYSTEM TO GO QUASI-STATIONARY OVER
THE NEXT 36 HOURS. AFTER TAU 36, THE SYSTEM WILL TRACK EASTWARD AS
THE NEAR-EQUATORIAL RIDGE LOCATED TO THE NORTH WILL BUILD AND BECOME
THE DOMINANT STEERING MECHANISM FOR THE REMAINDER OF THE FORECAST
PERIOD. TC 15S IS FORECAST TO SLOWLY INTENSIFY OVER THE NEXT 60
HOURS DUE TO WEAKENING VWS AND FAVORABLE SEA SURFACE TEMPERATURES
(29-30 CELSIUS), REACHING A PEAK INTENSITY JUST PRIOR TO MAKING
LANDFALL ALONG THE CENTRAL MADAGASCAR COAST. THE CYCLONE WILL BEGIN
TO WEAKEN AS IT DETERIORATES DUE TO LAND INTERACTION, LEADING TO
DISSIPATION OVER LAND BY THE END OF THE FORECAST PERIOD. DYNAMIC
MODEL GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT REGARDING THE
OVERALL TRACK; HOWEVER, THERE IS STILL A LARGE SPREAD IN THE TRACK
SPEED. DUE TO THIS UNCERTAINTY, THERE IS LOW CONFIDENCE IN THE JTWC
OFFICIAL FORECAST. JTWC WARNINGS FOR TC 15S HAVE BEEN SHIFTED TO
FIRST CYCLE FOR TRAINING PURPOSES. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 061800Z IS 14 FEET. NEXT WARNINGS AT 070900Z AND 072100Z.//
=========================================================================
WTXS31 PGTW 20150307 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 005
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   070600Z --- NEAR 16.2S 41.0E
     MOVEMENT PAST SIX HOURS - 315 DEGREES AT 03 KTS
     POSITION ACCURATE TO WITHIN 020 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   REPEAT POSIT: 16.2S 41.0E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   071800Z --- 15.9S 41.2E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
070900Z POSITION NEAR 16.1S 41.1E.
TROPICAL CYCLONE 15S (FIFTEEN), LOCATED APPROXIMATELY 380 NM WEST-
NORTHWEST OF ANTANANARIVO, MADAGASCAR, HAS TRACKED NORTHWESTWARD AT
03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS THE LOW LEVEL CIRCULATION CENTER HAS BECOME RAGGED AND
ALMOST FULLY-EXPOSED AS THE CENTRAL CONVECTION CONTINUES TO BE
SHEARED WESTWARD. THE INITIAL POSITION IS BASED ON THE ABOVE
ANIMATION WITH GOOD CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN
OVERALL ASSESSMENT OF DVORAK ESTIMATES FROM PGTW, KNES, AND FMEE.
UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS 04 DEGREES NORTH OF THE
RIDGE AXIS IN AN AREA OF MODERATE (15-20 KNOT) VERTICAL WIND SHEAR.
HOWEVER, A WESTWARD OUTFLOW CHANNEL IS ALSO PROVIDING VENTILATION TO
THE WAYWARD CONVECTION. TC 15S IS QUASI-STATIONARY IN A COL AREA
AMIDST THREE COMPETING STEERING FORCES: A NEAR-EQUATORIAL RIDGE TO
THE NORTH, A SUBTROPICAL RIDGE (STR) TO THE SOUTHWEST, AND ANOTHER
STR LEAF TO THE EAST. THE CYCLONE HAS WEAKENED TO BELOW THE JTWC
WARNING CRITERIA AND IS NOT EXPECTED TO REGAIN INTENSITY AND MOMENTUM
AT LEAST OVER THE NEXT 24 HOURS. THIS IS THE FINAL WARNING ON THIS
SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL
BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 070600Z IS 12 FEET.//

Tropical cyclone tracks developed by Michael Bath using operational warnings and advisories.


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Document: tropical_cyclone_201515_jtwc_advisories.htm Updated: 2 May 2017