Tropical Cyclone FAIDA Advisory Bulletin (JTWC)
WTPS31 PGTW 190900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 31P (THIRTYONE) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 31P (THIRTYONE) WARNING NR 005
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
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WARNING POSITION:
190600Z --- NEAR 12.7S 141.1E
MOVEMENT PAST SIX HOURS - 200 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 030 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
REPEAT POSIT: 12.7S 141.1E
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FORECASTS:
12 HRS, VALID AT:
191800Z --- 13.0S 140.6E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 270 DEG/ 03 KTS
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24 HRS, VALID AT:
200600Z --- 13.0S 139.9E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 280 DEG/ 06 KTS
---
36 HRS, VALID AT:
201800Z --- 12.8S 138.6E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 280 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
210600Z --- 12.5S 137.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 290 DEG/ 10 KTS
---
72 HRS, VALID AT:
220600Z --- 11.2S 133.2E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 295 DEG/ 08 KTS
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LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
230600Z --- 9.8S 130.2E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
VECTOR TO 120 HR POSIT: 310 DEG/ 04 KTS
---
120 HRS, VALID AT:
240600Z --- 8.8S 128.9E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
190900Z POSITION NEAR 12.8S 141.0E.
19APR25. TROPICAL CYCLONE 31P (THIRTYONE), LOCATED APPROXIMATELY
597 NM EAST OF DARWIN, AUSTRALIA, HAS TRACKED SOUTH-SOUTHWESTWARD
AT 05 KNOTS OVER THE PAST SIX HOURS.
MINIMUM CENTRAL PRESSURE AT 190600Z IS 1000 MB. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 190600Z IS 12 FEET. NEXT WARNINGS AT
191500Z, 192100Z, 200300Z AND 200900Z.//
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Tropical Cyclone FAIDA Forecast Advisory (JTWC)
WDPS31 PGTW 190900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 31P (THIRTYONE) WARNING
NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 12.7S 141.1E
INITIAL INTENSITY: 30 KTS
GEOGRAPHIC REFERENCE: 597 NM EAST OF DARWIN, AUSTRALIA
MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 05 KTS
SIGNIFICANT WAVE HEIGHT: 12 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 31P WITH A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER
(LLCC) AND DEEP CONVECTION FLARING ALONG THE SOUTHERN SEMICIRCLE. A
190430Z AMSR2 89 GHZ MICROWAVE IMAGE REVEALED THE WELL-DEFINED
LOW-LEVEL CLOUDS BANDS WRAPPING INTO THE CENTER. 31P APPEARS TO HAVE
STARTED ITS WESTWARD TURN, EVIDENT BY THE SOUTHWESTWARD JOG OVER
THE PAST 6 HOURS OR SO. THE CURRENT POSITION IS ANALYZED TO BE
ABOUT 48 NM DUE WEST OF WEIPA, AUSTRALIA. ENVIRONMENTAL ANALYSIS
INDICATES THAT 31P IS IN A MARGINAL ENVIRONMENT CHARACTERIZED BY
WEAK POLEWARD OUTFLOW ALOFT, MODERATE (15-20 KTS) NORTHEASTERLY
VERTICAL WIND SHEAR, SLIGHT DRY AIR ENTRAINMENT, AND WARM (29-30 C)
SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLCC IN ANIMATED MSI. THE
INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON PERSISTENCE FROM EARLIER ASCAT DATA, AGENCY DVORAK CI
ESTIMATES OF 1.5-2.0, AND THE OBJECTIVE INTENSITY ESTIMATES RANGING
FROM 26-36 KTS.
INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).
CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) POSITIONED TO THE SOUTHEAST.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T2.0 - 30 KTS
KNES: T1.5 - 25 KTS
DEMS: T2.0 - 30 KTS
CIMSS SATCON: 36 KTS AT 190540Z
CIMSS ADT: 34 KTS AT 190600Z
CIMSS AIDT: 30 KTS AT 190600Z
CIMSS DPRINT: 27 KTS AT 190600Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
VWS: 15-20 KTS
SST: 29-30 CELSIUS
OUTFLOW: WEAK POLEWARD
OTHER FACTORS: SLIGHT DRY AIR ENTRAINMENT ALONG THE NORTHERN
PORTION OF THE SYSTEM
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: NOT APPLICABLE
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TC 31P IS FORECAST TO TRACK WEST-SOUTHWESTWARD
OVER THE NEXT 12 HOURS BEFORE THE STR BUILDS IN TO THE SOUTH OF THE
VORTEX AND BEGINS PROPAGATING WESTWARD. NEAR TAU 24, THE SYSTEM IS
FORECAST TO START ON A WEST-NORTHWESTWARD TRACK AS THE SYSTEM RIDES
ALONG THE NORTHERN PERIPHERY OF THE STR THROUGH THE REMAINDER OF
THE FORECAST PERIOD. REGARDING INTENSITY, 31P IS FORECAST TO BEGIN
SLIGHTLY INTENSIFYING WITHIN THE GULF OF CARPENTARIA AS THE VORTEX
BECOMES BETTER ALIGNED THROUGH THE MID-LEVELS AND THE ENVIRONMENT
MOISTENS. A PEAK OF AROUND 40 KTS IS FORECAST TO OCCUR BETWEEN TAU
36 AND 48, BEFORE THE SYSTEM BEGINS TO SKIRT ALONG THE NORTHERN TOP
END. AFTER TAU 48, 31P IS FORECAST TO REMAIN RIGHT AROUND 35 KTS
THROUGH TAU 96 DUE TO LAND INTERACTION AND AN OVERALL MARGINAL
ENVIRONMENT. AFTER TAU 96, UPPER-LEVEL SHEAR IS EXPECTED TO
INCREASE TO NEAR 25 KTS, CAUSING THE VORTEX TO FURTHER SHALLOW AND
EVENTUALLY DISSIPATE NEAR TAU 120.
MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN MODERATE
AGREEMENT THROUGH TAU 72 WITH A 130 NM CROSS-TRACK SPREAD AT TAU
72. NAVGEM MAKES UP FOR THE MAJORITY OF THE SPREAD THOUGH,
TRACKING THE VORTEX FURTHER SOUTHWARD THAN THE REMAINDER OF
GUIDANCE. AFTER TAU 72, ALONG-TRACK SPREAD INCREASES SIGNIFICANTLY
WITH ECMWF AND GFS ACCELERATING THE VORTEX NORTHWESTWARD WHILE
GALWEM, UKMET, AND NAVGEM DEPICT SLOWER TRACK SPEEDS. THE JTWC
TRACK FORECAST IS PLACED SLIGHTLY CLOSER TO THE GFS AND ECMWF
MODELS WITH MEDIUM CONFIDENCE THROUGH TAU 72 AND LOW CONFIDENCE
THEREAFTER. INTENSITY GUIDANCE AGREES ON MARGINAL INTENSIFICATION
THROUGH TAU 42 AND THEN A STEADY INTENSITY THROUGH TAU 96 AND
WEAKENING THROUGH TAU 120. NOTABLY, GFS KEEPS THE SYSTEM WEAKER
THAN MESOSCALE MODELS DO, BUT ALSO HAS THE VORTEX TRACK CLOSER TO
THE TOP END THAN HAFS-A, HWRF, AND COAMPS-TC DOES. OVERALL, THE
JTWC INTENSITY FORECAST IS PLACED WITH MEDIUM CONFIDENCE. THE
AMOUNT OF LAND INTERACTION WILL PLAY A BIG ROLE IN HOW MUCH THE
SYSTEM IS ABLE TO DEVELOP.
FORECAST CONFIDENCE:
TRACK 0 - 72 HR: MEDIUM
TRACK 72-120 HR: LOW
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
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