WDXS31 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 29S (ERROL)     
WARNING NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.1S 119.7E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 270 NM NORTH-NORTHWEST OF BROOME,
                         AUSTRALIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) HAS RAPIDLY INTENSIFIED 40 KNOTS OVER THE PAST 
24 HOURS FROM 40 KNOTS AT 150000Z TO THE CURRENT INTENSITY ESTIMATE 
OF 80 KNOTS. AS INDICATED IN ANIMATED ENHANCED INFRARED (EIR) 
SATELLITE IMAGERY, THE SYSTEM HAS IMPROVED QUICKLY AND DRAMATICALLY, 
RAPIDLY FORMING A PINHOLE EYE WITHIN A COMPACT CORE, WITH EYE 
TEMPERATURES DECREASING TO ABOUT -23C AS OF 160110Z. AN UNOFFICIAL 
DVORAK ESTIMATE AT 160050Z WOULD YIELD A T5.5 (102 KNOTS), WHICH IS 
SUBSTANTIALLY HIGHER THAN THE 160000Z OFFICIAL AGENCY DVORAK 
INTENSITY ESTIMATES UPON WHICH THIS WARNING IS BASED. CIMSS OBJECTIVE 
INTENSITY ESTIMATES HAVE CONTINUED TO LAG BELOW THE SUBJECTIVE DVORAK 
ESTIMATES. HOWEVER, THE 160100Z CIMSS ADT ESTIMATE JUST SWITCHED TO 
THE EYE PATTERN, WITH RAW T-NUMBERS JUMPING TO 5.2 (95 KNOTS). THE 
INITIAL INTENSITY OF 80 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED 
ON THE PGTW AND KNES ESTIMATES AT 152330-152340Z. ANY CHANGES AFTER 
160000Z WILL BE REFLECTED IN THE NEXT JTWC INTENSITY FORECAST. 
ENVIRONMENTAL CONDITIONS REMAIN HIGHLY FAVORABLE, WITH RADIAL 
OUTFLOW, LOW VERTICAL WIND SHEAR AND WARM SST VALUES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE SOUTH AND SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   APRF: T4.0 - 65 KTS
   CIMSS SATCON: 55 KTS AT 152204Z
   CIMSS ADT: 53 KTS AT 152330Z
   CIMSS AIDT: 51 KTS AT 152330Z
   CIMSS D-MINT: 55 KTS AT 152203Z
   CIMSS D-PRINT: 50 KTS AT 152330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: ROBUST POLEWARD OUTFLOW CHANNEL

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: DUE TO THE DEVELOPMENT OF A PINHOLE
EYE AND RAPID CONSOLIDATION, THE PEAK INTENSITY FORECAST THROUGH
TAU 24 HAS BEEN INCREASED TO 120 KNOTS. 

FORECAST DISCUSSION: TC 29S IS TRACKING SLOWLY WESTWARD ALONG THE
NORTHERN PERIPHERY OF THE STR AND IS FORECAST TO CONTINUE TRACKING
WESTWARD TO WEST-SOUTHWESTWARD THROUGH TAU 24. AFTER TAU 12, THE
SYSTEM WILL SLOW AND TURN SHARPLY SOUTHWARD TO SOUTHEASTWARD AS A
MAJOR TROUGH APPROACHES AND DEEPENS OVER WESTERN AUSTRALIA, QUICKLY
BREAKING DOWN THE STR. ENVIRONMENTAL CONDITIONS WILL REMAIN HIGHLY
FAVORABLE THROUGH TAU 18, WITH IMPROVED POLEWARD OUTFLOW ENHANCED
BY THE UPPER-LEVEL TROUGH AND SUBTROPICAL JET OVER NORTHWEST 
AUSTRALIA. CONSEQUENTLY, RAPID INTENSIFICATION WILL CONTINUE 
UNABATED, WITH A PEAK INTENSITY OF AT LEAST 120 KNOTS FORECAST BY
TAU 12. NEAR TAU 24, ENVIRONMENTAL CONDITIONS WILL RAPIDLY DEGRADE AS 
THE SYSTEM TRACKS UNDER STRONG WESTERLIES ASSOCIATED WITH THE 
AFOREMENTIONED TROUGH. TC ERROL WILL TRACK EAST-SOUTHEASTWARD THROUGH 
THE END OF THE FORECAST PERIOD WITHIN WESTERLY STEERING FLOW BETWEEN 
THE NEAR-EQUATORIAL RIDGE TO THE NORTH AND THE LONGWAVE TROUGH
ENTRENCHED TO THE SOUTH. THE SYSTEM WILL WEAKEN RAPIDLY DUE TO
EXTENSIVE DRY AIR ENTRAINMENT AND INCREASING (30-50 KNOTS) VERTICAL
WIND SHEAR, WITH DISSIPATION EXPECTED BY TAU 96.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN FAIR AGREEMENT 
DUE TO THE COMPLEX, RAPIDLY EVOLVING STEERING ENVIRONMENT. THE JTWC 
TRACK FORECAST, HOWEVER, REMAINS HIGHLY CONSISTENT WITH THE PREVIOUS 
FORECAST TRACK. RAPID INTENSIFICATION GUIDANCE CONTINUES TO TRIGGER 
SUPPORTING THE RI PHASE OF THE FORECAST. ENSEMBLE GUIDANCE FROM THE 
ECENS AND GEFS ENSEMBLES SUPPORT THE JTWC TRACK FORECAST AND ALSO 
SHOW UNCERTAINTY IN THE RECURVE POINT AND EAST-SOUTHEASTWARD TRACK 
TOWARD NORTHWEST AUSTRALIA. 

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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