WDXS32 PGTW 270900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06S (ANGGREK) WARNING 
NR 025//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.9S 82.0E
   INITIAL INTENSITY: 100 KTS
   GEOGRAPHIC REFERENCE: 899 NM SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 48 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A COMPACT,
SYMMETRICAL, AND DENSE SYSTEM WITH A RECENTLY CLOUD-COVERED PINHOLE
EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
EXTRAPOLATION FROM A 270402Z ASCAT BULLSEYE PASS. THE INITIAL
INTENSITY IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE PGTW AND DEMS 
DVORAK ESTIMATES OF T5.5 (102KTS) WHICH IS MORE REPRESENTATIVE THAN 
THE AUTOMATED DVORAK ESTIMATES THAT ARE UNDERESTIMATING THE INTENSITY
OF THIS MIDGET SYSTEM.  THIS INTENSITY IS ALSO CONSISTENT WITH THE
SUSTAINED 12-HR CONVECTIVE SIGNATURE. ANALYSIS INDICATES A HIGHLY
FAVORABLE ENVIRONMENT WITH LOW VWS, WARM SST, AND MODERATE RADIAL
OUTFLOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA. 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   DEMS: T5.5 - 102 KTS
   CIMSS ADT: 74 KTS AT 270600Z
   CIMSS AIDT: 84 KTS AT 270600Z
   CIMSS DPRINT: 63 KTS AT 270600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC ANGGREK WILL CONTINUE ON A
WEST-SOUTHWESTWARD TO SOUTHWESTWARD TRACK UNDER THE STEERING
INFLUENCE OF THE STR. AFTER TAU 48, IT WILL TURN MORE POLEWARD AS
IT ROUNDS THE STR AXIS, RECURVE AND ACCELERATE SOUTHEASTWARD AS THE
STR RECEDES IN RESPONSE TO AN APPROACHING MID-LATITUDE TROUGH FROM
THE SOUTHWEST. THE HIGHLY FAVORABLE ENVIRONMENT WILL FUEL A STEADY
INTENSIFICATION TO A PEAK OF 110KTS BY TAU 48, AFTERWARD,
INCREASING VWS ASSOCIATED WITH THE STRONG WESTERLIES, THEN COOLING
SST WILL GRADUALLY ERODE THE SYSTEM. CONCURRENTLY, BY TAU 96, TC
08S WILL ENTER THE BAROCLINIC ZONE AND BEGIN EXTRA-TROPICAL
TRANSITION (ETT), AND BY TAU 120, WILL TRANSFORM INTO A STORM-FORCE
COLD CORE LOW. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH A
GRADUAL AND EVEN SPREAD TO A MERE 114NM BY TAU 72 LENDING HIGH
CONFIDENCE TO THIS PORTION OF THE JTWC TRACK FORECAST. AFTER TAU
72, THE SPREAD REMAINS RELATIVELY TIGHT AT 178NM BY TAU 120.
HOWEVER, GIVEN THE UNCERTAINTIES OF ETT, THERE IS ONLY MEDIUM
CONFIDENCE IN THE EXTENDED PORTION OF THE TRACK FORECAST. THE
INTENSITY FORECASTS ARE ALSO HIGH AND MEDIUM, RESPECTIVELY. 

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