WDXS31 PGTW 142100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 29S (TWENTYNINE) 
WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.6S 122.6E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 259 NM NORTH OF BROOME, AUSTRALIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: 
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A CONSOLIDATING 
SYSTEM, WITH DEEP CONVECTION BUILDING OVER THE SOUTHERN AND WESTERN 
QUADRANTS OF THE LOW-LEVEL CIRCULATION. ANIMATED WATER VAPOR IMAGERY 
REVEALS IMPROVED NEAR-RADIAL OUTFLOW, WITH ENHANCED POLEWARD OUTFLOW 
EXPANDING OVER THE SOUTHERN SEMICIRCLE. A 141919Z SSMIS 91GHZ 
MICROWAVE IMAGE AND RECENT ASCAT PASS, HOWEVER, CONTINUE TO INDICATE 
THE SYSTEM ISN'T VERTICALLY ALIGNED YET, WITH THE LOW-LEVEL 
CIRCULATION CENTER POSITIONED ON THE NORTHERN EDGE OF THE CORE 
CONVECTION. DEEP CONVECTIVE BANDING OVER THE SOUTHERN SEMICIRCLE HAS 
IMPROVED SIGNIFICANTLY, WRAPPING INTO THE SOUTHWESTERN QUADRANT OF 
THE SYSTEM. THE INITIAL INTENSITY IS ASSESSED AT 45 KNOTS BASED ON A 
BLEND OF SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES, WHICH RANGE 
FROM 30 TO 55 KNOTS.

INITIAL WIND RADII BASIS: OBTK 

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF THE SUBTROPICAL 
RIDGE (STR) POSITIONED TO THE SOUTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 55 KTS
   KNES: T2.5 - 35 KTS
   APRF: T2.0 - 30 KTS
   CIMSS ADT: 45 KTS AT 141800Z
   CIMSS AIDT: 37 KTS AT 141800Z
   CIMSS SATCON: 39 KTS AT 141900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: VERY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: NEAR-RADIAL 

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 29S IS FORECAST TO TRACK 
GENERALLY WESTWARD ALONG THE NORTHERN PERIPHERY OF THE STR THROUGH 
TAU 36. BY TAU 48, TC 29S WILL SLOW AND TURN SOUTHWESTWARD AS THE STR 
WEAKENS WITH THE APPROACH OF A LONGWAVE TROUGH OVER WESTERN 
AUSTRALIA. TC 29S IS FORECAST TO RAPIDLY INTENSIFY THROUGH TAU 48, 
WITH A PEAK INTENSITY OF 110 KNOTS EXPECTED AT TAU 48. THIS TROUGH 
WILL REMAIN ENTRENCHED OVER WESTERN AUSTRALIA THROUGH THE FORECAST 
PERIOD AND WILL ENVELOP THE SYSTEM AND DRIVE TC 29S EAST-
SOUTHEASTWARD AFTER TAU 48 TOWARD NORTHWESTERN AUSTRALIA. INCREASING 
VERTICAL WIND SHEAR OF 30-35 KNOTS AND DRY AIR ENTRAINMENT WILL LEAD 
TO RAPID WEAKENING AFTER TAU 48, WITH DISSIPATION ANTICIPATED BY TAU 
120.   

MODEL DISCUSSION: DETERMINISTIC GUIDANCE REMAINS IN FAIR AGREEMENT 
THROUGH TAU 36, WITH INCREASING UNCERTAINTY AFTER TAU 36 DUE TO THE 
COMPLEX INTERACTION WITH THE LONGWAVE TROUGH. THE BULK OF THE 
GUIDANCE SUPPORTS THE EAST-SOUTHEASTWARD TRACK. HOWEVER, TRACK SPEEDS 
VARY SIGNIFICANTLY BETWEEN THE DETERMINISTIC MODELS. ENSEMBLE 
GUIDANCE INDICATES A SIMILAR SPREAD LENDING LOW CONFIDENCE TO THE 
JTWC TRACK FORECAST AFTER TAU 72.    

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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