WTXS21 PGTW 20120110 08:30z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
180 NM EITHER SIDE OF A LINE FROM 14.6S 118.9E TO 23.4S 116.4E
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 22 TO 28 KNOTS. METSAT IM-
AGERY AT 100630Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 15.4S 118.8E. THE SYSTEM IS MOVING SOUTHWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 14.7S
118.9E IS NOW LOCATED NEAR 15.4S 118.8E, APPROXIMATELY 300 NM NORTH
OF PORT HEDLAND, AUSTRALIA. RECENT ANIMATED MULTISPECTRAL SATELLITE
IMAGERY INDICATES THAT ALTHOUGH THE CONVECTION IS FRAGMENTED AND
ORGANIZATION LACKING, THERE IS A TREND TOWARDS BETTER ORGANIZATION,
WITH DEEP CONVECTION CONSOLIDATING AROUND THE LOW LEVEL CIRCULATION
CENTER (LLCC). RECENT SCATTEROMETRY DATA REVEALS NUMEROUS 25 KNOT
WIND FLAGS NEAR THE CORE OF THE SYSTEM AND A BROAD FIELD OF GALE
FORCE WINDS BETWEEN THE SYSTEM AND THE PILBARA COAST. ANIMATED
INFRARED SATELLITE IMAGERY DEPICTS COOLING CLOUD TOPS OVER THE
SYSTEM CORE. ANIMATED WATER VAPOR IMAGERY REVEALS SOME INHIBITION TO
OUTFLOW OVER THE WESTERN QUADRANT, BUT ALSO SHOWS A VIGOROUS
POLEWARD OUTFLOW CHANNEL TO THE SOUTHEAST AND EXCELLENT OUTFLOW TO
THE EQUATORWARD SIDE. VERTICAL WIND SHEAR IS ESTIMATED AT 10 KNOTS
AND SEA SURFACE TEMPERATURES ARE A HIGHLY FAVORABLE 31 DEGREES.
SURFACE PRESSURE REPORTS AND DVORAK ESTIMATES ARE IN GOOD AGREEMENT
ON AN INTENSITY EQUATING TO 25 KNOTS. THE 100000Z PGTW UPPER LEVEL
STREAMLINE ANALYSIS REVEALS THAT THE LLCC IS JUST POLEWARD OF THE
SUBTROPICAL RIDGE AXIS AND MOVING TOWARDS AN AREA OF HIGHER VERTICAL
WIND SHEAR. THE SYSTEM IS TRACKING THROUGH A WEAKNESS IN THE
SUBTROPICAL RIDGE TOWARDS THE PILBARA COAST. THERE IS A REASONABLE
CHANCE THAT THE SYSTEM WILL FAIL TO REACH CYCLONE INTENSITY PRIOR TO
LANDFALL, BUT THE LATEST INTENSITY GUIDANCE INDICATES THE SYSTEM
WILL APPROACH THE 35 KNOT THRESHOLD DURING THE NEXT 12 TO 18 HOURS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 22 TO 28 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 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
110830Z.
=========================================================================
WTXS31 PGTW 20120110 21:00z AMD
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING AMENDED//
REF/A/NAVMARFCSTCEN PEARL HARBOR HI/100821Z JAN 12//
AMPN/TROPICAL CYCLONE FORMATION ALERT//
1. TROPICAL CYCLONE 06S (HEIDI) WARNING NR 001A AMENDED
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   101800Z --- NEAR 17.5S 118.9E
     MOVEMENT PAST SIX HOURS - 185 DEGREES AT 09 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: 17.5S 118.9E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   110600Z --- 19.4S 118.3E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 205 DEG/ 09 KTS
    ---
   24 HRS, VALID AT:
   111800Z --- 21.1S 117.5E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 36 HR POSIT: 210 DEG/ 09 KTS
    ---
   36 HRS, VALID AT:
   120600Z --- 22.6S 116.6E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 48 HR POSIT: 205 DEG/ 09 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   121800Z --- 24.3S 115.8E
   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 72 HR POSIT: 165 DEG/ 09 KTS
    ---
   72 HRS, VALID AT:
   131800Z --- 27.8S 116.9E
   MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
TROPICAL CYCLONE (TC) 06S (HEIDI) LOCATED NEAR 17.5S 118.9E,
APPROXIMATELY 170 NM NORTH OF PORT HEDLAND, AUSTRALIA, HAS TRACKED
SOUTHWARD AT 09 KNOTS OVER THE PAST 06 HOURS. ANIMATED INFRARED
SATELLITE IMAGERY AND A RECENT 101545Z TRMM 37H PASS INDICATE TC 06S
HAS CONTINUED TO IMPROVE OVER THE PAST SIX HOURS AND IS NOW AT
WARNING STATUS. OBSERVATIONS AT ROWLEY SHOALS INDICATE THE WINDS
HAVE INCREASED TO AT LEAST 35 KNOTS WITH CENTRAL PRESSURES NEAR 996
MB SUPPORTING THE CURRENT INTENSITY ESTIMATE. UPPER LEVEL ANALYSIS
INDICATES TC 06S IS LOCATED UNDER A SUBTROPICAL RIDGE AXIS, KEEPING
VERTICAL WIND SHEAR (VWS) LOW AND POLEWARD OUTFLOW FAVORABLE. SEA
SURFACE TEMPERATURES ARE BETWEEN 29-30 DEGREES CELSIUS AND ARE
FAVORABLE FOR FURTHER DEVELOPMENT OVER THE NEXT 24 HOURS. TC 06S
WILL CONTINUE TO TRACK SOUTH-SOUTHWESTWARD OVER THE NEXT 48 HOURS
AROUND A MID-LEVEL SUBTROPICAL RIDGE AS THE RIDGE SLOWLY BUILDS
WESTWARD. LANDFALL IS EXPECTED IN THE NEXT 18 TO 24 HOURS WITH A
SLOW WEAKENING OF THE SYSTEM BEGINNING AFTER LANDFALL AS VWS
INCREASES AND SURFACE CONDITIONS HAMPER THE SUSTAINMENT OF THE LOW
LEVEL CIRCULATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 101800Z IS
10 FEET. NEXT WARNINGS AT 110300, 110900Z, 111500Z AND 112100Z. THIS
WARNING SUPERSEDES AND CANCELS REF A, NAVMARFCSTCEN 100821Z JAN 12
TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 100830). JUSTIFICATION
FOR AMENDMENT: ADDED TAU 72 POSITION AND ADJUSTED DISSIPATION
TIMELINE.//
=========================================================================
WTXS31 PGTW 20120111 03:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
1. TROPICAL CYCLONE 06S (HEIDI) 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:
   110000Z --- NEAR 18.5S 118.9E
     MOVEMENT PAST SIX HOURS - 180 DEGREES AT 10 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 - 025 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   REPEAT POSIT: 18.5S 118.9E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   111200Z --- 20.2S 118.2E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
                            090 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 210 DEG/ 09 KTS
    ---
   24 HRS, VALID AT:
   120000Z --- 21.7S 117.2E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 36 HR POSIT: 210 DEG/ 07 KTS
    ---
   36 HRS, VALID AT:
   121200Z --- 22.9S 116.5E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 48 HR POSIT: 195 DEG/ 06 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   130000Z --- 24.1S 116.1E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 72 HR POSIT: 175 DEG/ 05 KTS
    ---
   72 HRS, VALID AT:
   140000Z --- 26.2S 116.3E
   MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
110300Z POSITION NEAR 18.9S 118.7E.
TROPICAL CYCLONE (TC) 06S (HEIDI) LOCATED NEAR 18.5S 118.9E,
APPROXIMATELY 110 NM NORTH OF PORT HEDLAND, AUSTRALIA, HAS TRACKED
SOUTHWARD AT 10 KNOTS OVER THE PAST 06 HOURS. ANIMATED INFRARED AND
MULTISPECTRAL SATELLITE IMAGERY AND RADAR DATA FROM PORT HEDLAND
DEPICT A WELL ORGANIZED LOW LEVEL CIRCULATION CENTER WITH HEAVY
BANDING CONVECTION LOCATED ON THE SOUTHERN PERIPHERY, WRAPPING
TOWARDS THE CENTER. CURRENT INTENSITY OF 40 KNOTS IS BASED ON LOCAL
OBSERVATIONS AND A CONSOLIDATION OF DVORAK FIXES RANGING FROM 2.5 TO
3.0. UPPER LEVEL ANALYSIS DEPICTS A WELL DEVELOPED POLEWARD OUTFLOW
CHANNEL BUT SUGGESTS TC 06S IS BEGINNING TO ENCOUNTER STRONGER
VERTICAL WIND SHEAR (VWS) (10-15 KNOTS) AS IT TRACKS SOUTH, CAUSING
SOME OF THE CENTRAL CONVECTION TO BE SLIGHTLY DISPLACED TO THE SOUTH-
SOUTHEAST. LOW TO MID-LEVEL SUBTROPICAL RIDGING CONTINUES TO BE THE
DOMINANT STEERING MECHANISM AND WILL SLOWLY CAUSE TC 06S TO TRACK
SOUTH-SOUTHWEST. LAND INTERACTION BETWEEN TAU 12 AND 24 WILL BEGIN
TO WEAKEN AND SLOW THE SYSTEM. ADDITIONALLY, AS TC 06S TRANSITS
AROUND THE STEERING RIDGE AND CHANGES DIRECTION, ANOTHER SLOW DOWN
IN TRACK SPEED IS EXPECTED BETWEEN TAU 48 AND 72. FRICTIONAL EFFECTS
AND VWS DURING THIS PERIOD WILL LEAD TO THE COMPLETE DISSIPATION OF
THE SYSTEM. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 110000Z IS 10 FEET.
NEXT WARNINGS AT 110900Z, 111500Z, 112100Z AND 120300Z.//
=========================================================================
WTXS31 PGTW 20120111 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 06S (HEIDI) WARNING NR 003//
1. TROPICAL CYCLONE 06S (HEIDI) 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:
   110600Z --- NEAR 19.2S 119.0E
     MOVEMENT PAST SIX HOURS - 200 DEGREES AT 08 KTS
     POSITION ACCURATE TO WITHIN 060 NM
     POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
     SATELLITE, RADAR AND SYNOPTIC DATA
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   REPEAT POSIT: 19.2S 119.0E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   111800Z --- 20.5S 117.9E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 210 DEG/ 08 KTS
    ---
   24 HRS, VALID AT:
   120600Z --- 21.9S 117.0E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 36 HR POSIT: 215 DEG/ 08 KTS
    ---
   36 HRS, VALID AT:
   121800Z --- 23.3S 116.0E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 48 HR POSIT: 225 DEG/ 07 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   130600Z --- 24.3S 114.9E
   MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
110900Z POSITION NEAR 19.5S 118.7E.
TROPICAL CYCLONE (TC) 06S (HEIDI) LOCATED NEAR 19.2S 119.0E,
APPROXIMATELY 80 NM NORTH-NORTHEAST OF PORT HEDLAND, AUSTRALIA, HAS
TRACKED SOUTH-SOUTHWESTWARD AT 08 KNOTS OVER THE PAST 06 HOURS.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND RADAR DATA FROM PORT
HEDLAND DEPICT A SYMMETRIC, TIGHTLY-ORGANIZED LOW LEVEL CIRCULATION
CENTER (LLCC) WITH ABUNDANT DEEP CONVECTION OVER THE SOUTHWESTERN
QUADRANT. IN ADDITION TO PROVIDING A BOOST TO POSITION CONFIDENCE,
AN 110142Z ASCAT PASS VERIFIES THE TIGHT ORGANIZATION OF THE LLCC.
ANIMATED RADAR IMAGERY FROM PORT HEDLAND ALSO CONFIRMS THAT THE
MAJORITY OF CONVECTION AND HEAVIEST PRECIPITATION LIES IN THE
SOUTHWESTERN QUADRANT OF THE STORM. AN 110015Z SSMIS IMAGE DEPICTS
THICK TIGHTLY CURVED BANDING ENCIRCLING THE LLCC AS WELL AS THE
BEGINNINGS OF A MICROWAVE EYE. THE CURRENT INTENSITY IS BASED ON AN
AVERAGE OF DVORAK ESTIMATES FROM PGTW, APRF, AND KNES AND SUPPORTED
BY SURFACE OBSERVATIONS FROM BEDOUT ISLAND. TC HEIDI IS TRACKING
ALONG THE SOUTHWESTERN PERIPHERY OF THE LOW- TO MID-LEVEL
SUBTROPICAL RIDGE THROUGH AN AREA OF 30 DEGREE SEA SURFACE
TEMPERATURES AND LOW VERTICAL WIND SHEAR. OVERALL, THE ENVIRONMENT
IS FAVORABLE FOR SLIGHT INTENSIFICATION PRIOR TO LANDFALL. ANIMATED
WATER VAPOR IMAGERY REVEALS A STRONG POLEWARD OUTFLOW CHANNEL, AND
THE 110000Z PGTW UPPER LEVEL STREAMLINE ANALYSIS DEPICTS A SINGULAR
POINT JUST TO THE NORTHEAST OF THE STORM. THE SYSTEM WILL MAKE
LANDFALL TO THE WEST OF PORT HEADLAND DURING THE NEXT 15 HOURS. THE
TRACK FORECAST STAYS EAST OF CONSENSUS IN ORDER TO COMPENSATE FOR
THE INFLUENCE OF WBAR, WHICH TRACKS THE SYSTEM INTO CENTRAL
AUSTRALIA. OTHER THAN WBAR, ALL CONSENSUS AIDS SHOW A SOUTHWESTERLY
TRACK AND DISSIPATION OVER LAND. AS TC 06S TRACKS SOUTHWARD,
VERTICAL WIND SHEAR WILL INCREASE, EXCEEDING 20 KNOTS BY TAU 36.
MEANWHILE, SOUTHEASTERLY FLOW IN THE BOUNDARY LEVEL WILL DRIVE THE
LLCC TO THE WEST. THE COMBINATION OF SOUTHEASTERLIES IN THE BOUNDARY
LEVEL AND NORTHWESTERLIES ALOFT PRESENT AN IDEAL ENVIRONMENT FOR DE-
COUPLING AND AN ACCELERATED RATE OF DISSIPATION. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 110600Z IS 12 FEET. NEXT WARNINGS AT 111500Z,
112100Z, 120300Z AND 120900Z.//
=========================================================================
WTXS31 PGTW 20120111 15:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 06S (HEIDI) WARNING NR 004//
1. TROPICAL CYCLONE 06S (HEIDI) 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:
   111200Z --- NEAR 19.6S 118.9E
     MOVEMENT PAST SIX HOURS - 195 DEGREES AT 04 KTS
     POSITION ACCURATE TO WITHIN 025 NM
     POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
     SATELLITE, RADAR AND SYNOPTIC DATA
   PRESENT WIND DISTRIBUTION:
   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 - 060 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   REPEAT POSIT: 19.6S 118.9E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   120000Z --- 20.8S 117.9E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 24 HR POSIT: 215 DEG/ 08 KTS
    ---
   24 HRS, VALID AT:
   121200Z --- 22.2S 116.9E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 36 HR POSIT: 215 DEG/ 08 KTS
    ---
   36 HRS, VALID AT:
   130000Z --- 23.6S 115.9E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
111500Z POSITION NEAR 19.9S 118.6E.
TROPICAL CYCLONE (TC) 06S (HEIDI) LOCATED NEAR 19.6S 118.9E,
APPROXIMATELY 45 NM NORTH-NORTHEAST OF PORT HEDLAND, AUSTRALIA, HAS
TRACKED SOUTH-SOUTHWESTWARD AT 04 KNOTS OVER THE PAST 06 HOURS.
ANIMATED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM BECOMING MORE
TIGHTLY WOUND AND CONVECTION GATHERING MORE DIRECTLY OVER THE TOP OF
THE SYSTEM. SURFACE OBSERVATIONS FROM BEDOUT ISLAND VERIFY AN
INTENSITY OF 55 KNOTS, WHICH MATCHES DVORAK ASSESSMENTS FROM KNES
AND APRF. AN 111041Z SSMIS IMAGE COMPARED WITH A PREVIOUS PASS
INDICATES THAT THE SYSTEM HAS PEAKED AND THE LOW LEVEL BANDING IS
BECOMING LESS CONCENTRIC. TC 06S IS TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF THE LOW- TO MID-LEVEL SUBTROPICAL RIDGE THROUGH AN AREA
OF 30 DEGREE SEA SURFACE TEMPERATURES AND LOW VERTICAL WIND SHEAR
AND WILL MAKE LANDFALL DURING THE NEXT 6 TO 10 HOURS BETWEEN PORT
HEDLAND AND POINT SAMSON. AS TC 06S TRACKS INLAND, VERTICAL WIND
SHEAR WILL ALSO INCREASE SHARPLY. MEANWHILE, SOUTHEASTERLY FLOW IN
THE BOUNDARY LEVEL WILL FORCE THE LOW LEVEL CIRCULATION CENTER TO
THE WEST. THE COMBINATION OF BOUNDARY LEVEL SOUTHEASTERLIES AND
NORTHWESTERLIES ALOFT WILL RESULT IN THE SYSTEM DE-COUPLING AND
DISSIPATING TO BELOW TROPICAL CYCLONE INTENSITY SHORTLY AFTER TAU
24. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 111200Z IS 12 FEET. NEXT
WARNINGS AT 120300Z AND 121500Z.//
=========================================================================
WTXS31 PGTW 20120111 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 06S (HEIDI) WARNING NR 005//
1. TROPICAL CYCLONE 06S (HEIDI) 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:
   111800Z --- NEAR 20.1S 118.7E
     MOVEMENT PAST SIX HOURS - 200 DEGREES AT 05 KTS
     POSITION ACCURATE TO WITHIN 020 NM
     POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
     SATELLITE AND RADAR
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   REPEAT POSIT: 20.1S 118.7E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   120600Z --- 21.4S 118.0E
   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 24 HR POSIT: 215 DEG/ 09 KTS
    ---
   24 HRS, VALID AT:
   121800Z --- 22.9S 116.8E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
112100Z POSITION NEAR 20.4S 118.5E.
TROPICAL CYCLONE (TC) 06S (HEIDI), LOCATED APPROXIMATELY 11 NM NNE
OF PORT HEDLAND, AUSTRALIA, HAS TRACKED SOUTH-SOUTHWESTWARD AT 05
KNOTS OVER THE PAST 06 HOURS. ANIMATED INFRARED SATELLITE IMAGERY
REVEALS THAT TC 06S HAS BEEN STEADILY WEAKENING OVER THE PAST 12
HOURS AND IS ABOUT TO MAKE LANDFALL ALONG THE WESTERN COAST OF
AUSTRALIA. THE LOW LEVEL CIRCULATION CENTER IS CLEARLY DISCERNIBLE
ON THE PORT HEDLAND COMPOSITE REFLECTIVITY RADAR LOOP. AN 1118Z
SURFACE OBSERVATION AT THAT STATION REPORTS WINDS OF 44 KNOTS,
GUSTING TO 55 KNOTS FROM THE SOUTH-SOUTHEAST. TC 06S IS EXPECTED TO
CONTINUE TRACKING OVER LAND IN A SOUTHWESTWARD DIRECTION AND TO
DISSIPATE RAPIDLY AS IT INTERACTS WITH THE LOCAL TOPOGRAPHY. 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 111800Z IS 12
FEET.//

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

Document: tropical_cyclone_heidi_jtwc_advisories.htm Updated: 17 June 2020 [Australian Severe Weather index] [Copyright Notice] [Email Contacts] [Search This Site] [Privacy Policy]