Tropical Cyclone SEAN (10S)

WTXS32 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 10S (SEAN) WARNING NR 012//
RMKS/
1. TROPICAL CYCLONE 10S (SEAN) WARNING NR 012    
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   201800Z --- NEAR 23.3S 110.0E
     MOVEMENT PAST SIX HOURS - 220 DEGREES AT 12 KTS
     POSITION ACCURATE TO WITHIN 030 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 105 KT, GUSTS 130 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 - 045 NM NORTHEAST QUADRANT
                            035 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            035 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT
                            160 NM SOUTHEAST QUADRANT
                            115 NM SOUTHWEST QUADRANT
                            120 NM NORTHWEST QUADRANT
   REPEAT POSIT: 23.3S 110.0E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   210600Z --- 24.9S 108.4E
   MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 010 NM NORTHEAST QUADRANT
                            010 NM SOUTHEAST QUADRANT
                            010 NM SOUTHWEST QUADRANT
                            010 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            150 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            110 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 210 DEG/ 09 KTS
    ---
   24 HRS, VALID AT:
   211800Z --- 26.5S 107.3E
   MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 010 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            010 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
                            030 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
                            150 NM SOUTHEAST QUADRANT
                            130 NM SOUTHWEST QUADRANT
                            090 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 200 DEG/ 06 KTS
    ---
   36 HRS, VALID AT:
   220600Z --- 27.6S 106.9E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            010 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            160 NM SOUTHEAST QUADRANT
                            130 NM SOUTHWEST QUADRANT
                            090 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 175 DEG/ 07 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   221800Z --- 28.9S 107.0E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
                            190 NM SOUTHEAST QUADRANT
                            160 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 150 DEG/ 11 KTS
    ---
   72 HRS, VALID AT:
   231800Z --- 32.5S 109.6E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
202100Z POSITION NEAR 23.7S 109.6E.
20JAN25. TROPICAL CYCLONE 10S (SEAN), LOCATED APPROXIMATELY 235
NM WEST-SOUTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED
SOUTHWESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. MINIMUM
CENTRAL PRESSURE AT 201800Z IS 948 MB. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 201800Z IS 36 FEET. NEXT WARNINGS AT 210300Z,
210900Z, 211500Z AND 212100Z.//
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WDXS32 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 10S (SEAN)      
WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.3S 110.0E
   INITIAL INTENSITY: 105 KTS
   GEOGRAPHIC REFERENCE: 235 NM WEST-SOUTHWEST OF LEARMONTH,
                         AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 36 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AFTER UNDERGOING AN EYEWALL REPLACEMENT CYCLE, TROPICAL CYCLONE
(TC) 10S TRACKED OVER COOLER SST (25-26C) AND WEAKENED SIGNIFICANTLY. 
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS RAPID 
DECAY OF THE EYEWALL AND LOSS OF THE EYE (AROUND 201630Z), WITH DEEP 
CONVECTION BECOMING INCREASINGLY DISORGANIZED. MICROWAVE IMAGERY IS 
LIMITED; HOWEVER, A 201805Z ATMS 89GHZ MICROWAVE IMAGE REVEALS A 
DEFINED LOW-LEVEL CIRCULATION CENTER POSITIONED ON THE NORTHWEST EDGE 
OF THE REMNANT EYEWALL, WITH SHALLOW CONVECTION OVER THE WESTERN 
SEMICIRCLE INDICATIVE OF THE RAPID WEAKENING TREND. ROBUST RADIAL 
OUTFLOW HAS PERSISTED, MAINTAINING THE RAPIDLY DWINDLING CORE 
CONVECTION. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE 
BASED ON THE EIR IMAGERY AND THE ATMS IMAGE. THE INITIAL INTENSITY OF 
105 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE DVORAK 
CURRENT INTENSITY ESTIMATES RANGING FROM 5.0-6.0 (90-115 KNOTS) AS 
WELL AS THE CIMSS ADT AND SATCON OBJECTIVE ESTIMATES (100-102 KNOTS).

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
ENTRENCHED OVER WESTERN AUSTRALIA.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   KNES: T5.5 - 102 KTS
   DEMS: T6.0 - 115 KTS
   APRF: T5.0 - 90 KTS
   CIMSS SATCON: 100 KTS AT 201800Z
   CIMSS ADT: 102 KTS AT 201800Z
   CIMSS AIDT: 91 KTS AT 201800Z
   CIMSS D-PRINT: 90 KTS AT 201800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 10S WILL TRACK SOUTHWESTWARD THROUGH TAU 24
THEN TURN SOUTHWARD THROUGH TAU 48 AS IT TRACKS ALONG THE WESTERN
PERIPHERY OF THE STR. SST VALUES WILL COOL STEADILY FROM ABOUT 25C
TO 22C BY TAU 48. STRONG VERTICAL WIND SHEAR (VWS) AND DRY AIR 
ENTRAINMENT WILL FURTHER DEGRADE ENVIRONMENTAL CONDITIONS AFTER TAU 
24 SUPPORTING A RAPID WEAKENING TREND. AFTER TAU 48, THE SYSTEM WILL 
RECURVE SOUTH-SOUTHEASTWARD AROUND THE SOUTHERN PERIPHERY OF THE STR, 
ENCOUNTERING STRONG WESTERLIES AND VWS ASSOCIATED WITH THE 
SUBTROPICAL JET. TC 10S WILL ENTER A VERY DRY ENVIRONMENT AND TRACK 
OVER COLD SST VALUES NEAR 20C, WHICH WILL LEAD TO DISSIPATION BY TAU 
72.    

MODEL DISCUSSION: DETERMINISTIC GUIDANCE IS NOW IN TIGHT AGREEMENT
THROUGH TAU 48, WITH A 50NM CROSS-TRACK SPREAD AT TAU 48, DIVERGING
TO ABOUT 110NM BY TAU 72. PROBABILISTIC GUIDANCE IS ALSO IN TIGHT
AGREEMENT THROUGH TAU 48, WITH INCREASING SPREAD AFTER TAU 48.
OVERALL TRACK CONFIDENCE IS ASSESSED AT HIGH.     

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM//
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