[Index]
Tropical Cyclone 201120
[Southern Hemisphere Summary][Summaries and Track Data]
| Tropical
Cyclones
[Index] |
Tropical Cyclone 201120 [Southern Hemisphere Summary][Summaries and Track Data] |
WTXS21 PGTW 20110401 16:30z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
130 NM EITHER SIDE OF A LINE FROM 12.9S 129.2E TO 14.8S 125.3E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME. WINDS
IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT IMAGERY,
SYNOPTIC DATA AND RADAR DATA AT 011600Z INDICATE THAT A CIRCULATION
CENTER IS LOCATED NEAR 13.2S 128.9E. THE SYSTEM IS MOVING
SOUTHWESTWARD AT 04 KNOTS.
2. REMARKS: ANIMATED INFRARED SATELLITE AND RADAR IMAGERY DEPICT A
CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH IMPROVED
CONVECTIVE BANDING WRAPPING INTO A DEFINED CENTER. ANIMATED WATER
VAPOR IMAGERY INDICATES THAT THE LLCC IS LOCATED JUST EQUATORWARD OF
THE RIDGE AXIS AND IS UNDER DIFFLUENT EASTERLY FLOW WITH MODERATE
VERTICAL WIND SHEAR (15-20 KNOTS). HOWEVER, POLEWARD OUTFLOW IS
GOOD, ENHANCED BY UPPER-LEVEL WESTERLIES OVER AUSTRALIA, WHILE
EQUATORWARD OUTFLOW IS RESTRICTED OVER THE NORTHEAST QUADRANT. A
011020Z SSMIS IMAGE ALSO SUPPORTS IMPROVED ORGANIZATION WITH
MULTIPLE CONVECTIVE BANDS WRAPPING INTO THE CENTER. A 011232Z ASCAT
IMAGE SHOWS 25-30 KNOT UNFLAGGED WINDS OVER THE WESTERN QUADRANT.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE
SYSTEM IS EXPECTED TO TRACK OVER OR JUST TO THE NORTH OF THE
AUSTRALIAN COAST WITH VERTICAL WIND SHEAR EXPECTED TO DECREASE IN
THE NEXT 24 HOURS, THEREFORE, THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
021630Z.//
=========================================================================
WTXS31 PGTW 20110402 03:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 20S (TWENTY) WARNING NR 001//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/011621ZAPR2011//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL CYCLONE 20S (TWENTY) 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:
020000Z --- NEAR 13.5S 127.6E
MOVEMENT PAST SIX HOURS - 250 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE AND RADAR
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 13.5S 127.6E
---
FORECASTS:
12 HRS, VALID AT:
021200Z --- 14.2S 126.1E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 245 DEG/ 08 KTS
---
24 HRS, VALID AT:
030000Z --- 14.9S 124.6E
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
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 245 DEG/ 08 KTS
---
36 HRS, VALID AT:
031200Z --- 15.6S 123.1E
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
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 250 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
040000Z --- 16.3S 121.3E
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
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 240 DEG/ 07 KTS
---
72 HRS, VALID AT:
050000Z --- 17.8S 118.8E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 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 - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 225 DEG/ 06 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
060000Z --- 19.4S 117.0E
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 195 DEG/ 06 KTS
---
120 HRS, VALID AT:
070000Z --- 21.8S 116.4E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
---
REMARKS:
020300Z POSITION NEAR 13.7S 127.2E.
TROPICAL CYCLONE (TC) 20S, LOCATED APPROXIMATELY 660 NM NORTHEAST OF
PORT HEDLAND, AUSTRALIA, HAS TRACKED WEST-SOUTHWESTWARD AT 08 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE AND RADAR
IMAGERY DEPICT A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH IMPROVED CONVECTIVE BANDING WRAPPING INTO A DEFINED CENTER.
ANIMATED WATER VAPOR IMAGERY INDICATES THAT THE LLCC IS LOCATED JUST
EQUATORWARD OF THE RIDGE AXIS AND IS UNDER DIFFLUENT EASTERLY FLOW
WITH MODERATE VERTICAL WIND SHEAR (15-20 KNOTS). HOWEVER, POLEWARD
OUTFLOW IS GOOD, ENHANCED BY UPPER-LEVEL WESTERLIES OVER AUSTRALIA,
WHILE EQUATORWARD OUTFLOW IS RESTRICTED OVER THE NORTHEAST QUADRANT.
A 012131Z SSMIS 37 GHZ IMAGE DEPICTS IMPROVED LOW-LEVEL CONVECTIVE
BANDING WRAPPING TIGHTLY INTO A WELL-DEFINED LLCC. AN EARLIER ASCAT
IMAGE AT 011232Z INDICATED 25-30 KNOT UNFLAGGED WINDS OVER THE
WESTERN QUADRANT AND BASED ON RECENT IMAGERY THE SYSTEM HAS
CONTINUED TO CONSOLIDATE. THE CURRENT POSITION IS BASED ON THE SSMIS
IMAGE AND RADAR IMAGERY WITH GOOD CONFIDENCE. THE CURRENT INTENSITY
IS BASED ON A DVORAK ESTIMATE OF 35 KNOTS FROM PGTW. TC 20S IS
FORECAST TO TRACK WESTWARD THROUGH TAU 72 UNDER THE STEERING
INFLUENCE OF A DEEP SUBTROPICAL RIDGE POSITIONED OVER AUSTRALIA. THE
SYSTEM SHOULD RE-CURVE AHEAD OF A DEEP MIDLATITUDE SHORT-WAVE TROUGH
WHICH IS FORECAST TO DEEPEN OVER WESTERN AUSTRALIA AFTER TAU 72.
DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT WITH THE EXCEPTION OF
NOGAPS, WHICH ERRONEOUSLY TRACKS THE SYSTEM WESTWARD THROUGH THE
PERIOD DESPITE A SIMILAR DEPICTION OF THE DEEPENING TROUGH. THIS
FORECAST IS POSITIONED CLOSE TO THE MODEL CONSENSUS THROUGH TAU 72
BUT IS POLEWARD IN THE EXTENDED TAUS DUE TO THE PROBLEM WITH THE
NOGAPS TRACKER. TC 20S IS FORECAST TO INTENSIFY AT A SLOW RATE
THROUGH TAU 36 DUE TO MODERATE VERTICAL WIND SHEAR AND LAND
INTERACTION. AFTERWARDS, THE SYSTEM SHOULD INTENSIFY AT A 25-30 KNOT
RATE PER DAY UNTIL IT MAKES LANDFALL NEAR TAU 120. THIS WARNING
SUPERSEDES AND CANCELS REF A, NAVMARFCSTCEN 011621Z APR 11 TROPICAL
CYCLONE FORMATION ALERT (WTXS21 PGTW 011630). MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 020000Z IS 10 FEET. NEXT WARNINGS AT 021500Z AND
030300Z.//
=========================================================================
WTXS31 PGTW 20110402 15:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 20S (TWENTY) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 20S (TWENTY) 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:
021200Z --- NEAR 14.1S 126.8E
MOVEMENT PAST SIX HOURS - 225 DEGREES AT 04 KTS
POSITION ACCURATE TO WITHIN 030 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE AND RADAR
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 14.1S 126.8E
---
FORECASTS:
12 HRS, VALID AT:
030000Z --- 14.8S 125.4E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 245 DEG/ 08 KTS
---
24 HRS, VALID AT:
031200Z --- 15.5S 123.9E
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
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 250 DEG/ 07 KTS
---
36 HRS, VALID AT:
040000Z --- 16.0S 122.5E
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
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 250 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
041200Z --- 16.5S 121.0E
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
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 250 DEG/ 07 KTS
---
72 HRS, VALID AT:
051200Z --- 17.5S 118.2E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 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 - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 245 DEG/ 06 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
061200Z --- 18.5S 115.8E
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 210 DEG/ 04 KTS
---
120 HRS, VALID AT:
071200Z --- 19.9S 114.9E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
021500Z POSITION NEAR 14.3S 126.4E.
TROPICAL CYCLONE (TC) 20S (TWENTY), LOCATED APPROXIMATELY 875 NM
EAST-NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWESTWARD
AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED WATER VAPOR IMAGERY
SHOWS CENTRAL CONVECTION ASSOCIATED WITH THE SYSTEM HAS REDUCED AS
THE LOW LEVEL CIRCULATION CENTER (LLCC) MOVED ONSHORE NEAR KALUMBURU.
HOWEVER, CONVECTIVE BANDS REMAIN INTACT AND TIGHTLY WRAPPED INTO THE
LLCC AS EVIDENCED ON RADAR LOOP FROM WYNDHAM. THE INITIAL POSITION IS
BASED ON THE ABOVE RADAR ANIMATION WITH A FAIR DEGREE OF CONFIDENCE.
THE INITIAL INTENSITY IS BASED ON DVORAK ESTIMATE OF 35 KNOTS FROM
KNES, PGTW, AND APRF. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS
JUST TO THE NORTH OF A RIDGE AXIS IN AN AREA OF LIGHT TO MODERATE
VERTICAL WIND SHEAR. A ROBUST OUTFLOW CHANNEL EXISTS POLEWARD OF THE
RIDGE AXIS. TC 20S IS EXPECTED TO STRADDLE THE KIMBERLY COAST BEFORE
IT RE-ENTERS THE WARM WATERS OF THE SOUTHERN INDIAN OCEAN BY TAU 24.
FAVORABLE ENVIRONMENTAL CONDITIONS WILL FUEL A SLIGHTLY ABOVE NORMAL
INTENSIFICATION, PEAKING AT 90 KTS AT TAU 96 BEFORE IT BEGINS TO
RECURVE POLEWARD TOWARDS LEARMONTH WITH THE APPROACH OF A
MID-LATITUDE TROUGH FROM THE SOUTHWEST. THE AVAILABLE NUMERIC
GUIDANCE IS IN OVERALL GOOD AGREEMENT WITH THIS TRACK WITH THE
EXCEPTION OF NOGAPS THAT FAVORS A WESTWARD MOVEMENT AFTER TAU 48,
INDICATING MINIMAL IMPACT FROM THE MID-LATITUDE TROUGH. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 021200Z IS 8 FEET. NEXT WARNINGS AT
030300Z AND 031500Z.//
=========================================================================
WTXS31 PGTW 20110403 03:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 20S (TWENTY) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 20S (TWENTY) 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:
030000Z --- NEAR 15.2S 125.1E
MOVEMENT PAST SIX HOURS - 230 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE AND RADAR
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 15.2S 125.1E
---
FORECASTS:
12 HRS, VALID AT:
031200Z --- 15.8S 124.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 240 DEG/ 06 KTS
---
24 HRS, VALID AT:
040000Z --- 16.4S 122.8E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 250 DEG/ 08 KTS
---
36 HRS, VALID AT:
041200Z --- 16.9S 121.3E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 255 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
050000Z --- 17.4S 119.6E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 245 DEG/ 07 KTS
---
72 HRS, VALID AT:
060000Z --- 18.5S 116.8E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 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 - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 220 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
070000Z --- 20.1S 115.3E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 190 DEG/ 05 KTS
---
120 HRS, VALID AT:
080000Z --- 22.1S 115.0E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
---
REMARKS:
030300Z POSITION NEAR 15.4S 124.8E.
TROPICAL CYCLONE (TC) 20S, LOCATED APPROXIMATELY 760 NM EAST-
NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWESTWARD AT 09
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS RAPIDLY DECAYING DEEP CONVECTION DUE TO LAND
INTERACTION AS TC 20S CONTINUES TO TRACK ALONG THE KIMBERLY COAST.
ANIMATED WATER VAPOR IMAGERY INDICATES THAT THE LLCC HAS TRACKED
UNDER THE UPPER-LEVEL RIDGE AXIS, THEREFORE, VERTICAL WIND SHEAR HAS
DECREASED AND OUTFLOW HAS IMPROVED. RECENT MICROWAVE IMAGERY TO
INCLUDE A 022128Z CORIOLIS IMAGE AND A 022341Z SSMIS IMAGE CONTINUE
TO SHOW OVERALL TIGHTLY-CURVED LOW-LEVEL CONVECTIVE BANDING WITH
FRAGMENTED DEEP CONVECTIVE BANDING OVER THE EAST AND SOUTHWEST
QUADRANTS. THE TOTAL PRECIPITABLE WATER PRODUCT INDICATES A DEEP
MOISTURE ENVELOPE WITH SOME DRY AIR OVER THE WEST AND NORTHWEST
PERIPHERY OF THE SYSTEM. THE CURRENT POSITION IS BASED ON RADAR
IMAGERY AND THE MSI WITH FAIR CONFIDENCE. THE CURRENT INTENSITY
IS BASED ON PERSISTENCE DUE TO THE LACK OF DVORAK ESTIMATES OVER
LAND. TC 20S IS FORECAST TO TRACK WESTWARD THROUGH TAU 72 UNDER THE
STEERING INFLUENCE OF A DEEP SUBTROPICAL RIDGE POSITIONED OVER
AUSTRALIA. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT SO THIS
FORECAST IS POSITIONED CLOSE TO THE MODEL CONSENSUS. THE DYNAMIC
MODELS, HOWEVER, INDICATE A WEAK SYSTEM WITH PEAK INTENSITIES LESS
THAN 50 KNOTS. NOGAPS AND GFDN PEAK TC 20S AT ABOUT 40 KNOTS. THIS
LACK OF INTENSIFICATION IN THE MODELS IS LIKELY DUE TO THE FLAT
INTENSIFICATION TREND OVER THE PAST DAY AS TC 20S TRACKED OVER LAND
AND POSSIBLY DUE TO FORECASTED DRY AIR ENTRAINMENT HINDERING
SIGNIFICANT DEVELOPMENT. THE DYNAMIC MODELS FURTHER WEAKEN THE
SYSTEM AFTER TAU 72 AND TRACK IT UNDER A STRONG LOW-LEVEL RIDGE
EXPECTED TO BUILD IN AFTER A DEEP MIDLATITUDE SHORTWAVE TROUGH AND
FRONT MOVE INTO WESTERN AUSTRALIA. THIS FORECAST REMAINS CONSISTENT
WITH PREVIOUS FORECASTS AND IS BASED ON THE SYSTEM INTENSIFYING TO A
PEAK INTENSITY NEAR 75-80 KNOTS AS IT TRACKS OVER WARM SST WITH
FAVORABLE CONDITIONS PREVAILING AFTER TAU 24. THEREFORE, THE SYSTEM
IS EXPECTED TO RE-CURVE AHEAD OF A DEEP MIDLATITUDE SHORT-WAVE
TROUGH AFTER TAU 72. AT THIS TIME, THE WEAKENING/DISSIPATIOJN
SCENARIO IS DEEMED UNLIKELY. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
030000Z IS 8 FEET. NEXT WARNINGS AT 031500Z AND 040300Z.//
=========================================================================
WTXS31 PGTW 20110403 15:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 20S (TWENTY) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 20S (TWENTY) 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:
031200Z --- NEAR 15.5S 124.4E
MOVEMENT PAST SIX HOURS - 240 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE AND RADAR
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
REPEAT POSIT: 15.5S 124.4E
---
FORECASTS:
12 HRS, VALID AT:
040000Z --- 16.0S 123.4E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 260 DEG/ 06 KTS
---
24 HRS, VALID AT:
041200Z --- 16.2S 122.2E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 255 DEG/ 07 KTS
---
36 HRS, VALID AT:
050000Z --- 16.6S 120.7E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 250 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
051200Z --- 17.2S 119.1E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 235 DEG/ 07 KTS
---
72 HRS, VALID AT:
061200Z --- 18.7S 116.6E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 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 - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 210 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
071200Z --- 20.4S 115.6E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 185 DEG/ 06 KTS
---
120 HRS, VALID AT:
081200Z --- 22.6S 115.3E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
031500Z POSITION NEAR 15.6S 124.1E.
TROPICAL CYCLONE (TC) 20S (TWENTY), LOCATED APPROXIMATELY 710 NM
EAST-NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWESTWARD
AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED WATER VAPOR IMAGERY
SHOWS WEAKENED CONVECTIVE BANDING AS THE SYSTEM CONTINUES TO TRACK
ALONG THE RUGGED KIMBERLY COAST. THE INITIAL POSITION IS BASED ON
A RADAR LOOP FROM WYNDHAM AND FROM A 030955Z SSMI-S MICROWAVE IMAGE
WITH GOOD CONFIDENCE. THE INITIAL INTENSITY IS EXTRAPOLATED FROM
NEARBY SURFACE OBSERVATIONS. TC 20S IS POISED TO EXIT INTO THE WARM
WATERS OF THE SOUTH INDIAN OCEAN. UPPER LEVEL ANALYSIS INDICATES THE
SYSTEM IS JUST UNDERNEATH THE RIDGE AXIS IN AN AREA OF LOW VERTICAL
WIND SHEAR AND INCREASING POLEWARD OUTFLOW. THIS IS ALSO EVIDENT ON
THE ANIMATED WATER VAPOR IMAGERY. AS TC 20S CONTINUES TO TRACK ALONG
THE NORTHWEST PERIPHERY OF THE STEERING SUBTROPICAL RIDGE TO THE
SOUTHEAST, IT WILL GRADUALLY INTENSIFY AT A SLIGHTLY HIGHER THAN
NORMAL RATE, PEAKING AT 80 KNOTS BEFORE IT BEGINS TO RECURVE TO THE
SOUTH NEAR LEARMONTH IN RESPONSE TO A DEEP MID-LATITUDE TROUGH
APPROACHING FROM THE SOUTHWEST. THE AVAILABLE NUMERIC GUIDANCE ARE IN
GOOD AGREEMENT WITH THIS TRACK FORECAST UP TO TAU 48 WHERE THEY
CONTINUE TO TRACK THE SYSTEM WESTWARD. THIS SCENARIO IS BASED ON A
SIGNIFICANTLY WEAKENED SYSTEM TRACKING ALONG THE NORTHERN PERIPHERY
OF A SHALLOW SUBTROPICAL RIDGE TRAILING BEHIND THE AFOREMENTIONED
TROUGH. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 031200Z IS 10 FEET. NEXT
WARNINGS AT 040300Z AND 041500Z.//
=========================================================================
WTXS31 PGTW 20110404 03:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 20S (TWENTY) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 20S (TWENTY) 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:
040000Z --- NEAR 16.4S 123.5E
MOVEMENT PAST SIX HOURS - 250 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 16.4S 123.5E
---
FORECASTS:
12 HRS, VALID AT:
041200Z --- 16.6S 122.5E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 250 DEG/ 07 KTS
---
24 HRS, VALID AT:
050000Z --- 17.1S 121.2E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 255 DEG/ 07 KTS
---
36 HRS, VALID AT:
051200Z --- 17.5S 119.8E
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
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 245 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
060000Z --- 18.3S 118.0E
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
055 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 245 DEG/ 07 KTS
---
72 HRS, VALID AT:
070000Z --- 19.4S 115.5E
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 - 060 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 285 DEG/ 07 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
080000Z --- 18.7S 112.5E
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: 300 DEG/ 09 KTS
---
120 HRS, VALID AT:
090000Z --- 16.9S 109.1E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
040300Z POSITION NEAR 16.5S 123.2E.
TROPICAL CYCLONE (TC) 20S, LOCATED APPROXIMATELY 640 NM EAST-
NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED WEST-SOUTHWESTWARD AT
06 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A SIGNIFICANTLY WEAKENED, EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH ISOLATED DEEP CONVECTION FLARING OVER
THE SOUTHEAST QUADRANT. A 032250Z TRMM 37 GHZ IMAGE SHOWS A WEAK,
BUT DISCERNIBLE LLCC JUST OFF THE COAST OF AUSTRALIA. BASED ON THIS
IMAGERY, THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION. THE
CURRENT INTENSITY OF 25 KNOTS IS BASED PRIMARILY ON NUMEROUS SURFACE
OBSERVATIONS WHICH INDICATE SUSTAINED WINDS OF ONLY 15-21 KNOTS NEAR
THE CENTER. THE CURRENT FORECAST DEPARTS SIGNIFICANTLY FROM THE
PREVIOUS FORECAST DUE TO THE RAPID WEAKENING IN INTENSITY OVER THE
PAST 24 HOURS AS THE SYSTEM TRACKED UNEXPECTEDLY SOUTHWESTWARD OVER
LAND. ADDITIONALLY, THE TOTAL PRECIPITABLE WATER PRODUCTS AND
SOUNDINGS NOW PROVIDE CLEAR EVIDENCE OF THE PRESENCE OF DRY AIR WEST
OF THE SYSTEM, WHICH WILL SERVE TO HINDER SIGNIFICANT DEVELOPMENT.
TC 20S IS NOW FORECAST TO TRACK WESTWARD UNDER THE STEERING
INFLUENCE OF A DEEP SUBTROPICAL RIDGE OVER AUSTRALIA AND WITH A
SLIGHT STAIR-STEP WEST-SOUTHWESTWARD NEAR TAU 72 IN RESPONSE TO A
MIDLATITUDE TROUGH MOVING INTO WESTERN AUSTRALIA. AFTER TAU 72, THE
LOW- TO MID-LEVEL RIDGE IS EXPECTED TO BUILD SOUTH OF THE SYSTEM
ALLOWING THE SYSTEM TO TURN WEST-NORTHWESTWARD. THE DECISION TO
CHANGE THE FORECAST PHILOSOPHY IS BASED ON A MUCH WEAKER SYSTEM
PEAKING AT 45-55 KNOTS, WHICH IS UNLIKELY TO RE-CURVE, AND THE
STRONG RIDGING BUILDING BEHIND THE TROUGH. DYNAMIC MODEL GUIDANCE IS
IN GOOD AGREEMENT, SUPPORTING THE CURRENT FORECAST. RELIABLE
INTENSITY GUIDANCE HAS ALSO COME INTO CLOSER AGREEMENT ESPECIALLY
GFDN AND STIPS, WHICH SUPPORT THE INTENSITY FORECAST. TC 20S IS
FORECAST TO DISSIPATE BY TAU 120 DUE TO THE INTRUSION OF COOLER,
MORE STABLE AIR ASSOCIATED WITH THE STRONG RIDGE. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 040000Z IS 10 FEET. NEXT WARNINGS AT
041500Z AND 050300Z.//
=========================================================================
WTXS31 PGTW 20110404 15:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 20S (TWENTY) WARNING NR 006//
RMKS/
1. TROPICAL CYCLONE 20S (TWENTY) WARNING NR 006
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
041200Z --- NEAR 16.3S 122.4E
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
REPEAT POSIT: 16.3S 122.4E
---
FORECASTS:
12 HRS, VALID AT:
050000Z --- 16.5S 121.3E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
041500Z POSITION NEAR 16.4S 122.1E.
TROPICAL CYCLONE (TC) 20S (TWENTY), LOCATED APPROXIMATELY 590 NM
NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED WESTWARD AT 05 KTS
OVER THE PAST SIX HOURS. ANIMATED INFRARED IMAGERY SHOWS THE LOW
LEVEL CIRCULATION CENTER (LLCC) CONTINUES TO TRACK OVER WATER BUT HAS
BECOME BROAD AND DISFIGURED. THE CENTRAL CONVECTION HAS ALL BUT
DISSIPATED WITH REMNANT CONVECTION OVER LAND AND DETACHED FROM THE
LLCC. THE INITIAL POSITION, BASED ON ANIMATED INFRARED SATELLITE
IMAGERY, HAS BEEN DIFFICULT TO PINPOINT. THE INITIAL INTENSITY IS
EXTRAPOLATED FROM NEARBY SURFACE OBSERVATIONS AS DVORAK INTENSITY
ESTIMATES FROM TRACKING AGENCIES HAVE CEASED DUE TO CLOUD SIGNATURE
BEING UNCLASSIFIABLE. TC 20S IS EXPECTED TO REMAIN AS A WEAK
DISTURBANCE AND DRIFT WESTWARD ALONG THE NORTHERN PERIPHERY OF THE
STEERING RIDGE TO THE SOUTH. 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 041200Z IS 8 FEET.//
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| Document: tropical_cyclone_201120.htm | Updated: 5 April 2011 |