WDXS32 PGTW 242100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06S (ANGGREK)
WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.4S 91.1E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 1180 NM EAST-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 06S (ANGGREK) HAVING RAPIDLY INTENSIFIED OVER THE PAST
12 HOURS, EXPOSING A RAGGED EYE NEAR 241430Z. DESPITE RELATIVELY
SLOW TRACK SPEED (1-3 KTS), TC ANGGREK HAS TAKEN ADVANTAGE OF A
FAVORABLE ENVIRONMENT WITH VERY LOW (0-5 KTS) VERTICAL WIND SHEAR
(VWS), WARM (27-28 C) SEA SURFACE TEMPERATURES (SST) AND GOOD
DUAL-CHANNEL OUTFLOW. ANIMATED EIR IMAGERY HAS ALSO CAPTURED THE TC
EXPERIENCING TROCHOIDAL MOTION ALONG THE SOUTHWARD TRACK, WITH THE
EYE FEATURE WOBBLING AROUND THE LOW LEVEL CIRCULATION CENTER
(LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON A RAGGED EYE FEATURE OBSERVED IN METSAT EIR IMAGERY AT 241800Z,
MEASURING 26NM IN DIAMETER WITH A TEMPERATURE OF 7.8C. THE INITIAL
INTENSITY OF 80 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
SUBJECTIVE AND OBJECTIVE INTENSITY GUIDANCE LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T4.5 - 77 KTS
   APRF: T5.0 - 90 KTS
   CIMSS SATCON: 74 KTS AT 241845Z
   CIMSS ADT: 94 KTS AT 241845Z
   CIMSS AIDT: 82KTS AT 241845Z
   CIMSS DPRINT: 80KTS AT 241900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TC 06S IS FORECAST TO TRACK SOUTHWESTWARD
THROUGH TAU 48, FURTHER INTENSIFYING ALONG-TRACK AS TRACK SPEEDS
INCREASE SLIGHTLY AND NEGATE UPWELLING OF COOLER OCEAN WATERS THAT
MAY BE CURRENTLY RESTRAINING FURTHER INTENSIFICATION. AFTER TAU 48,
THE SYSTEM IS FORECAST TO SLIGHTLY TURN TO A WEST-SOUTHWESTWARD
TRACK DUE TO THE STEERING INFLUENCE OF A STR TO THE SOUTH UNTIL TAU
96 WHEN THE SYSTEM ROUNDS THE STR ON A SOUTHWESTWARD TRACK. FURTHER
INTENSIFICATION IS LIKELY TO OCCUR, AS THE ENVIRONMENT IS
ANTICIPATED TO REMAIN VERY FAVORABLE THROUGH THE FORECAST INTERVAL.

MODEL DISCUSSION: GLOBAL NUMERICAL MODEL GUIDANCE IS IN EXCEPTIONAL
AGREEMENT REGARDING THE TRACK OF TC 06S. INTENSITY GUIDANCE,
HOWEVER, IS IN MODERATE DISAGREEMENT. WITH THE EXCEPTION OF NAVGEM,
A VERY TIGHT CROSS-TRACK SPREAD OF 33NM IS PRESENT AT TAU 72
BETWEEN THE JTWC CONSENSUS MEMBERS. THE LARGEST UNCERTAINTY
REGARDING TRACK FORECAST IS IN TRACK SPEEDS, WITH THE JTWC
CONSENSUS SHOWING A 263NM ALONG-TRACK SPREAD AT TAU 120.  INTENSITY
GUIDANCE SHOWS A RATHER LARGE SPREAD AMONG CONSENSUS MEMBERS, WITH
THE LARGEST UNCERTAINTY PRESENT AT TAU 84 WITH A 60 KNOT SPREAD
BETWEEN GFS AND COAMPS-TC.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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