WDXS32 PGTW 282100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06S (ANGGREK)   
WARNING NR 028//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.7S 73.2E
   INITIAL INTENSITY: 115 KTS
   GEOGRAPHIC REFERENCE: 877 NM SOUTH OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 48 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
COMPACT SYSTEM WITH A CLEAR, SYMMETRIC 15 NM EYE, WHICH SUPPORTS THE 
INITIAL POSITION WITH HIGH CONFIDENCE. ANIMATED WATER VAPOR IMAGERY 
SHOWS THAT THE SYSTEM HAS UNOBSTRUCTED RADIAL OUTFLOW ALOFT 
INDICATING A HIGHLY FAVORABLE ENVIRONMENT. THE INITIAL INTENSITY IS 
ASSESSED WITH HIGH CONFIDENCE BASED ON THE PGTW AND KNES SUBJECTIVE 
DVORAK INTENSITY ESTIMATES AND CIMSS SATCON ESTIMATE. THE INITIAL 
WIND RADII VALUES ARE BASED ON A DETAILED ANALYSIS OF RECENT ASCAT 
DATA WITH HIGH CONFIDENCE.  

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   KNES: T6.0 - 115 KTS
   CIMSS SATCON: 113 KTS AT 281730Z
   CIMSS ADT: 109 KTS AT 281830Z
   CIMSS AIDT: 108 KTS AT 281830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 06S IS CURRENTLY
TRACKING WEST-SOUTHWESTWARD ALONG THE NORTHWESTERN PERIPHERY OF THE 
STR TO THE SOUTH. TC 06S IS FORECASTED TO MAINTAIN ITS INTENSITY OF 
115 KNOTS OVER THE NEXT 12 HOURS AS IT BEGINS TO TRACK MORE
SOUTHWESTWARD AND START TO ROUND THE WESTERN PERIPHERY OF THE STR. 
BOTH THE SMALL EYE AND CONVECTIVE STRUCTURE ARE HIGHLY SYMMETRICAL, 
WHICH COULD SUPPORT AN INCREASE IN INTENSITY OVER THE NEXT 6-12 
HOURS. AFTERWARDS, THE SYSTEM WILL RECURVE SOUTHEASTWARD AND BEGIN
EXTRATROPICAL TRANSITION (ETT) NEAR TAU 48 WITH RAPID WEAKENING DUE 
TO VERY HIGH (50 KTS) VERTICAL WIND SHEAR AND COOLER (23-24 C) SEA 
SURFACE TEMPERATURES. BY TAU 72, TC 06S WILL COMPLETE ETT AND BECOME 
EMBEDDED IN THE STRONG MIDLATITUDE WESTERLIES UNDER THE POLAR FRONT 
JET.  

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN EXCEPTIONAL
AGREEMENT THROUGH THE FORECAST PERIOD. DESPITE A FEW ECMWF ENSEMBLE
SOLUTIONS HAVING THE SYSTEM CURVE TO THE NORTHEAST, THE LARGE
MAJORITY OF ECMWF AND GFS ENSEMBLE SOLUTIONS ARE IN GOOD AGREEMENT
LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. RELIABLE
INTENSITY GUIDANCE SUPPORTS THE JTWC INTENSITY FORECAST WITH MEDIUM
CONFIDENCE THROUGH THE FORECAST PERIOD.

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