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

WTXS21 PGTW 20150126 13:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
195 NM EITHER SIDE OF A LINE FROM 15.8S 79.7E TO 20.9S 75.7E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 28 TO 33 KNOTS. METSAT
IMAGERY AT 261130Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 16.8S 78.7E. THE SYSTEM IS MOVING WEST-SOUTHWESTWARD AT 13
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 15.8S
81.3E IS NOW LOCATED NEAR 16.8S 78.7E, APPROXIMATELY 670 NM SOUTH-
SOUTHEAST OF DIEGO GARCIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
AND A 261133Z SSMIS MICROWAVE IMAGE DEPICT DEEPENED CONVECTION WITH
TIGHTLY- CURVED BANDING OVER THE EASTERN SEMI-CIRCLE WRAPPING INTO A
CONSOLIDATING LOW-LEVEL CIRCULATION CENTER. UPPER-LEVEL ANALYSIS
INDICATES THE DISTURBANCE IS LOCATED IN A FAVORABLE ENVIRONMENT WITH
LOW (05 TO 15 KNOT) VERTICAL WIND SHEAR AND GOOD DUAL OUTFLOW
CHANNELS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB.
DUE TO INCREASED CONSOLIDATION AND IMPROVED UPPER-LEVEL CONDITIONS,
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
271300Z.//
=========================================================================
WTXS31 PGTW 20150126 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 08S (EIGHT) WARNING NR 001//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/261251ZJAN2015//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL CYCLONE 08S (EIGHT) 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:
   261800Z --- NEAR 17.1S 78.1E
     MOVEMENT PAST SIX HOURS - 240 DEGREES AT 06 KTS
     POSITION ACCURATE TO WITHIN 020 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: 17.1S 78.1E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   270600Z --- 17.7S 77.7E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 180 DEG/ 03 KTS
    ---
   24 HRS, VALID AT:
   271800Z --- 18.4S 77.7E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
                            035 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            055 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 145 DEG/ 03 KTS
    ---
   36 HRS, VALID AT:
   280600Z --- 18.9S 78.1E
   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
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 135 DEG/ 03 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   281800Z --- 19.4S 78.6E
   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
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 140 DEG/ 04 KTS
    ---
   72 HRS, VALID AT:
   291800Z --- 20.7S 79.7E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 140 DEG/ 08 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   301800Z --- 23.0S 81.9E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 120 HR POSIT: 140 DEG/ 12 KTS
    ---
   120 HRS, VALID AT:
   311800Z --- 26.7S 85.5E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
REMARKS:
262100Z POSITION NEAR 17.3S 78.0E.
TROPICAL CYCLONE (TC) 08S (EIGHT), LOCATED APPROXIMATELY 684 NM
SOUTH-SOUTHEAST OF DIEGO GARCIA, HAS TRACKED WEST-SOUTHWESTWARD AT 06
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS THE SYSTEM HAS MODERATELY DEEPENED AND
EXPANDED AS THE FORMATIVE BANDS WRAPPED TIGHTER INTO THE LOW LEVEL
CIRCULATION CENTER. THE INITIAL POSITION IS BASED ON THE EIR
ANIMATION AND EXTRAPOLATED FROM RECENT MICROWAVE SATELLITE PASSES
WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS HELD SLIGHTLY HIGHER
THAN AGENCY DVORAK ESTIMATES TO REFLECT THE DEEPENED AND INCREASED
CONSOLIDATION OF THE CYCLONE. UPPER LEVEL ANALYSIS INDICATES THE
SYSTEM IS JUST NORTH OF THE RIDGE AXIS IN AN AREA OF LIGHT TO
MODERATE (10-20 KNOT) VERTICAL WIND SHEAR (VWS) THAT IS EASILY OFFSET
BY EXCELLENT RADIAL OUTFLOW. TC 08S IS CURRENTLY TRACKING ALONG THE
NORTHERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE SOUTHWEST.
OVER THE NEXT 36 HOURS, THE CYCLONE IS FORECAST TO RECURVE
SOUTHEASTWARD AS THE NEAR EQUATORIAL RIDGE TO THE NORTH ASSUMES
STEERING AS THE STR WEAKENS. THE SYSTEM WILL SEE A MODERATE INCREASE
IN INTENSITY, PEAKING AT 60 KNOTS BY TAU 36-48. AFTERWARDS,
INCREASING VWS AND COOLING SEA SURFACE TEMPERATURES WILL GRADUALLY
ERODE THE CYCLONE. THE INITIAL SET OF NUMERIC GUIDANCE IS WIDELY
SPREAD; HOWEVER, THERE IS A GENERAL AGREEMENT IN THE RECURVATURE
SCENARIO. IN VIEW OF THE GUIDANCE SPREAD, THERE IS LOW CONFIDENCE IN
THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 261800Z
IS 10 FEET. NEXT WARNINGS AT 270900Z AND 272100Z. THIS SUPERSEDES
REF A (WTXS21 PGTW 261300).//
=========================================================================
WTXS31 PGTW 20150127 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 08S (EIGHT) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 08S (EIGHT) 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:
   270600Z --- NEAR 18.1S 77.9E
     MOVEMENT PAST SIX HOURS - 150 DEGREES AT 06 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 - 100 NM NORTHEAST QUADRANT
                            100 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            085 NM NORTHWEST QUADRANT
   REPEAT POSIT: 18.1S 77.9E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   271800Z --- 18.4S 78.1E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
                            110 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            095 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 145 DEG/ 03 KTS
    ---
   24 HRS, VALID AT:
   280600Z --- 18.9S 78.5E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
                            120 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            095 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 140 DEG/ 04 KTS
    ---
   36 HRS, VALID AT:
   281800Z --- 19.5S 79.0E
   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
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            095 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 140 DEG/ 05 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   290600Z --- 20.3S 79.7E
   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
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            095 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 145 DEG/ 08 KTS
    ---
   72 HRS, VALID AT:
   300600Z --- 22.8S 81.5E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
                            120 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            095 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 150 DEG/ 09 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   310600Z --- 25.9S 83.5E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 120 HR POSIT: 145 DEG/ 11 KTS
    ---
   120 HRS, VALID AT:
   010600Z --- 29.4S 86.6E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
270900Z POSITION NEAR 18.2S 77.9E.
TROPICAL CYCLONE 08S (EIGHT), LOCATED APPROXIMATELY 732 NM SOUTH-
SOUTHEAST OF DIEGO GARCIA, HAS TRACKED SOUTH-SOUTHEASTWARD AT 06
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL (MSI)
SATELLITE IMAGERY SHOWS THE SYSTEM HAS CONTINUED TO DEEPEN AND
HAS EXPANDED, SPECIFICALLY TOWARDS THE EAST. THE INITIAL POSITION IS
BASED ON THE MSI ANIMATION LOOP AND A 270555Z TRMM IMAGE WHICH
DEPICTS THE BULK OF THE DEEP CONVECTION ON THE EASTERN SIDE OF THE
LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL INTENSITY IS STILL
HELD HIGHER THAN THE DVORAK INTENSITY ESTIMATES DUE TO A 270414Z
PARTIAL ASCAT PASS WHICH REFLECTS WINDS OF 35 KTS OVER 15ONM FROM
THE LLCC. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS IN LIGHT TO
MODERATE (10-20 KNOT) VERTICAL WIND SHEAR (VWS) WHICH IS OFFSET BY
RADIAL OUTFLOW. TC 08S IS CURRENTLY TRACKING ALONG THE SOUTHERN
PERIPHERY OF A NEAR EQUATORIAL RIDGE (NER). FOR THE REMAINDER OF THE
FORECAST PERIOD, THE SYSTEM WILL SLOWLY TRACK TO THE SOUTHEAST AS
THE NER BUILDS IN AND FORCES TC 08S POLEWARD. WHILE THE SYSTEM WILL
CONTINUE TO CONSOLIDATE AND STRENGTHEN OVER THE NEXT 36 HOURS,
EXPECT FAIRLY RAPID WEAKENING BEYOND THIS TIME FRAME DUE TO
INCREASED VWS AND POOR OCEAN HEAT CONTENT CONDITIONS SOUTH OF 24
DEGREES SOUTH. DUE TO A VARIED SPREAD IN THE TRACK BASED ON DYNAMIC
MODEL GUIDANCE, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST
TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 270600Z IS 12 FEET. NEXT
WARNINGS AT 272100Z AND 280900Z.//
=========================================================================
WTXS31 PGTW 20150127 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 08S (DIAMONDRA) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 08S (DIAMONDRA) 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:
   271800Z --- NEAR 18.7S 77.7E
     MOVEMENT PAST SIX HOURS - 165 DEGREES AT 04 KTS
     POSITION ACCURATE TO WITHIN 030 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
                            100 NM SOUTHEAST QUADRANT
                            080 NM SOUTHWEST QUADRANT
                            085 NM NORTHWEST QUADRANT
   REPEAT POSIT: 18.7S 77.7E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   280600Z --- 19.1S 78.0E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
                            110 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            095 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 135 DEG/ 03 KTS
    ---
   24 HRS, VALID AT:
   281800Z --- 19.5S 78.4E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
                            130 NM SOUTHEAST QUADRANT
                            110 NM SOUTHWEST QUADRANT
                            115 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 135 DEG/ 06 KTS
    ---
   36 HRS, VALID AT:
   290600Z --- 20.4S 79.3E
   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
                            030 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
                            140 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            125 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 145 DEG/ 07 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   291800Z --- 21.5S 80.2E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
                            140 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            125 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 145 DEG/ 08 KTS
    ---
   72 HRS, VALID AT:
   301800Z --- 24.2S 82.4E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
272100Z POSITION NEAR 18.8S 77.8E.
TROPICAL CYCLONE (TC) 08S (DIAMONDRA), LOCATED APPROXIMATELY 759 NM
SOUTH-SOUTHEAST OF DIEGO GARCIA, HAS TRACKED SOUTH-SOUTHEASTWARD
AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE
IMAGERY SHOWS THE SYSTEM HAS MAINTAINED DEEP CONVECTION AS IT SLOWED
DOWN IN ANTICIPATION OF A SOUTHEASTWARD PROGRESSION. THE INITIAL
POSITION IS BASED ON THE ABOVE ANIMATION AND ON RECENT MICROWAVE
PASSES WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN
OVERALL ASSESSMENT OF DVORAK ESTIMATES FROM PGTW, KNES, AND FMEE.
UPPER LEVEL ANALYSIS INDICATES THE SYSTEM HAS DRIFTED TO ABOUT 07
DEGREES SOUTH OF THE RIDGE AXIS IN AN AREA OF MODERATE (20-25 KNOT)
VERTICAL WIND SHEAR (VWS) THAT IS PARTIALLY OFFSET BY GOOD POLEWARD
OUTFLOW. THE CYCLONE HAS BEGUN TO TRACK UNDER THE INFLUENCE OF A
BUILDING NEAR-EQUATORIAL RIDGE (NER) TO THE NORTH. TC 08S IS EXPECTED
TO GRADUALLY ACCELERATE SOUTHEASTWARD ALONG THE SOUTHWESTERN
PERIPHERY OF THE NER. A FAVORABLE UPPER LEVEL ENVIRONMENT, IN
ADDITION TO WARM ALONG-TRACK SEA SURFACE TEMPERATURES (SSTS), WILL
PROMOTE MODERATE INTENSIFICATION, PEAKING AT 60 KNOTS BY TAU 36.
AFTERWARDS, INCREASING VWS ASSOCIATED WITH THE PREVAILING WESTERLIES
AND COOLING SSTS WILL RAPIDLY ERODE THE SYSTEM CAUSING ITS
DISSIPATION BY TAU 72. THE AVAILABLE NUMERIC GUIDANCE IS IN OVERALL
GOOD AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 271800Z IS 15 FEET. NEXT WARNINGS
AT 280900Z AND 282100Z.//
=========================================================================
WTXS31 PGTW 20150128 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 08S (DIAMONDRA) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 08S (DIAMONDRA) WARNING NR 004
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   280600Z --- NEAR 19.2S 79.3E
     MOVEMENT PAST SIX HOURS - 125 DEGREES AT 09 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
                            100 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            085 NM NORTHWEST QUADRANT
   REPEAT POSIT: 19.2S 79.3E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   281800Z --- 19.7S 80.1E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
                            110 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            095 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 125 DEG/ 04 KTS
    ---
   24 HRS, VALID AT:
   290600Z --- 20.2S 80.8E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
                            130 NM SOUTHEAST QUADRANT
                            110 NM SOUTHWEST QUADRANT
                            100 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 130 DEG/ 08 KTS
    ---
   36 HRS, VALID AT:
   291800Z --- 21.2S 82.0E
   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 - 100 NM NORTHEAST QUADRANT
                            130 NM SOUTHEAST QUADRANT
                            110 NM SOUTHWEST QUADRANT
                            100 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 150 DEG/ 09 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   300600Z --- 22.8S 83.1E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            105 NM SOUTHWEST QUADRANT
                            095 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 140 DEG/ 10 KTS
    ---
   72 HRS, VALID AT:
   310600Z --- 25.8S 85.8E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
280900Z POSITION NEAR 19.3S 79.5E.
TROPICAL CYCLONE 08S (DIAMONDRA), LOCATED APPROXIMATELY 827 NM
SOUTH-SOUTHEAST OF DIEGO GARCIA, HAS TRACKED SOUTHEASTWARD AT 09
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL (MSI) SATELLITE
IMAGERY SHOWS THE SYSTEM HAS MAINTAINED ITS LEVEL OF DEEP CONVECTION
AS IT CONTINUES TO TRACK TO THE SOUTHEAST. A 280353 METOP-B
MICROWAVE IMAGE REVEALS THAT THE BULK OF THE DEEP CONVECTION IS
CONCENTRATED IN THE EASTERN AND SOUTHERN AREAS OF THE SYSTEM WITH
THE CURRENT POSITION BASED ON THE ABOVE IMAGERY. UPPER-LEVEL
ANALYSIS SHOWS THAT TC DIAMONDRA IS IN AN AREA OF MODERATE (20-30
KONTS) EASTERLY VERTICAL WIND SHEAR (VWS) WHICH IS CURRENTLY
COUNTERED BY GOOD POLEWARD OUTFLOW. THE INITIAL INTENSITY IS BASED
ON DVORAK ESTIMATES FROM PGTW, KNES, AND FMEE AS WELL AS A 280354Z
PARTIAL ASCAT ASSESSMENT. TC 08S WILL TRACK TO THE SOUTHEAST AS THE
SYSTEM CONTINUES TO BE INFLUENCED BY THE BUILDING NEAR EQUATORIAL
RIDGE (NER) TO THE NORTH. WHILE GOOD POLEWARD OUTFLOW WILL ALLOW THE
SYSTEM TO SLIGHTLY DEVELOP OVER THE NEXT 24 HOURS, EXPECT A RAPID
DISSIPATION OF THE SYSTEM AS UNFAVORABLE SEA SURFACE TEMPERATURES
AND INCREASING VWS AFFECT THE SYSTEM. EXPECT COMPLETE DISSIPATION BY
TAU 72 AS THE SYSTEM CROSSES THE 25TH PARALLEL. THE DYNAMIC NUMERIC
MODEL GUIDANCE IS IN OVERALL AGREEMENT LENDING HIGH CONFIDENCE TO
THE JTWC TRACK FORECAST, WHICH IS LAID CLOSE TO THE MULTI-MODEL
CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 280600Z IS 18 FEET.
NEXT WARNINGS AT 282100Z AND 290900Z. REFER TO TROPICAL CYCLONE 09S
(EUNICE) WARNINGS (WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES.//
=========================================================================
WTXS31 PGTW 20150128 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 08S (DIAMONDRA) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 08S (DIAMONDRA) 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:
   281800Z --- NEAR 19.9S 80.2E
     MOVEMENT PAST SIX HOURS - 125 DEGREES AT 06 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 - 070 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            075 NM SOUTHWEST QUADRANT
                            075 NM NORTHWEST QUADRANT
   REPEAT POSIT: 19.9S 80.2E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   290600Z --- 20.5S 80.8E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            065 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 135 DEG/ 06 KTS
    ---
   24 HRS, VALID AT:
   291800Z --- 21.4S 81.7E
   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 36 HR POSIT: 145 DEG/ 08 KTS
    ---
   36 HRS, VALID AT:
   300600Z --- 22.7S 82.7E
   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 48 HR POSIT: 135 DEG/ 08 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   301800Z --- 23.9S 84.0E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
282100Z POSITION NEAR 20.1S 80.4E.
TROPICAL CYCLONE (TC) 08S (DIAMONDRA), LOCATED APPROXIMATELY 889 NM
SOUTH-SOUTHEAST OF DIEGO GARCIA, HAS TRACKED SOUTHEASTWARD AT 06
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY REVEALS A SIGNIFICANT SHALLOWING OF DEEP CONVECTION AS THE
BANDING HAS BECOME SLIGHTLY DISORGANIZED AND THE LOW LEVEL
CIRCULATION CENTER (LLCC) HAS STARTED TO BECOME LESS DEFINED. A
281622Z AMSU-B MICROWAVE IMAGE ALSO SHOWS THIS WEAKENING OF THE
SYSTEM AS THE OVERALL STRUCTURE IS BEGINNING TO DETERIORATE. THE
CURRENT POSITION IS BASED ON THE MICROWAVE PASS AND THE PGTW AND
KNES POSITION FIXES WITH LOW CONFIDENCE DUE TO THE POOR DEFINITION
OF THE LLCC. THE CURRENT INTENSITY HAS BEEN DECREASED TO 40 KNOTS
DUE TO THE DECREASING STRUCTURE OF THE SYSTEM AND IS BETWEEN DVORAK
INTENSITY ESTIMATES THAT RANGE FROM 35 TO 45 KNOTS. UPPER-LEVEL
ANALYSIS REVEALS A DECREASING ENVIRONMENT AS INCREASING VERTICAL
WIND SHEAR, WHICH IS CURRENTLY ASSESSED AT MODERATE TO HIGH LEVELS
(20 TO 30 KNOTS), IS BEGINNING TO OFFSET STRONG POLEWARD OUTFLOW. TC
DIAMONDRA IS CURRENTLY TRACKING TO THE SOUTHEAST ALONG THE OUTER
PERIPHERY OF A MODIFYING SUBTROPICAL RIDGE (STR) LOCATED TO THE EAST
OF THE SYSTEM. THIS STR IS EXPECTED TO REMAIN THE DOMINANT STEERING
INFLUENCE THROUGH THE REMAINDER OF THE FORECAST PERIOD AS THE SYSTEM
IS EXPECTED TO TRACK TO THE SOUTHEAST. FURTHER INCREASING VWS, ALONG
WITH DECREASING SEA SURFACE TEMPERATURES, WILL CONTINUALLY ERODE THE
SYSTEM, LEADING TO COMPLETE DISSIPATION BY TAU 48. BASED ON THE
CURRENTLY OBSERVED HIGH LEVELS OF VWS, DISSIPATION SOONER THAN
FORECAST REMAINS A POSSIBILITY. NUMERIC MODEL GUIDANCE GENERALLY
AGREES WITH A SOUTHEAST TRACK, ALTHOUGH MODELS ARE FAIRLY SPREAD DUE
THE EXTENT OF THE STR. OVERALL, DUE TO THE LOW CONFIDENCE IN THE
INITIAL POSITION AND SPREAD IN THE GUIDANCE, FORECAST CONFIDENCE IS
LOW. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 281800Z IS 13 FEET. NEXT
WARNINGS AT 290900Z AND 292100Z. REFER TO TROPICAL CYCLONE 09S
(EUNICE) WARNINGS (WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES.//
=========================================================================
WTXS31 PGTW 20150129 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 08S (DIAMONDRA) WARNING NR 006//
RMKS/
1. TROPICAL CYCLONE 08S (DIAMONDRA) 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:
   290600Z --- NEAR 20.8S 80.2E
     MOVEMENT PAST SIX HOURS - 160 DEGREES AT 05 KTS
     POSITION ACCURATE TO WITHIN 020 NM
     POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
     SATELLITE AND SYNOPTIC DATA
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   SUBTROPICAL
   RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            140 NM SOUTHWEST QUADRANT
                            110 NM NORTHWEST QUADRANT
   REPEAT POSIT: 20.8S 80.2E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   291800Z --- 22.0S 81.0E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   SUBTROPICAL
    ---
REMARKS:
290900Z POSITION NEAR 21.1S 80.4E.
TROPICAL CYCLONE (TC) 08S (DIAMONDRA), LOCATED APPROXIMATELY 936 NM
SOUTH-SOUTHEAST OF DIEGO GARCIA, HAS TRACKED SOUTH-SOUTHEASTWARD
AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS DEMINISHING DEEP CONVECTION SHEARED
SOUTH-SOUTHEASTWARD OF A FULLY-EXPOSED LOW-LEVEL CIRCULATION
CENTER. A 290334Z ASCAT PASS REVEALS A 20 TO 25 KNOT CIRCULATION
WITH GALE FORCE WINDS EXTENDED ASYMMETRICALLY TO 100 NM FROM THE
CENTER AND STRONGER (UP TO 45 KNOTS) OVER THE SOUTHWESTERN QUADRANT.
BASED ON THE CURRENT ASSESSMENT, TC 08 IS CLASSIFIED AS A SUBTROPICAL
CYCLONE AND ASSUMES THE SUBTROPICAL CYCLONE CHARACTERISTICS.
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 290600Z
IS 13 FEET. REFER TO TROPICAL CYCLONE 09S (EUNICE) WARNINGS
(WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES.//

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


Document: tropical_cyclone_diamondra_jtwc_advisories.htm
Updated: 17 June 2020
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