WDXS32 PGTW 262100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06S (ANGGREK)    
WARNING NR 024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.2S 84.2E
   INITIAL INTENSITY: 105 KTS
   GEOGRAPHIC REFERENCE: 954 NM SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 44 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AFTER PEAKING AT 110 KNOTS AT 261200Z (BASED ON A 261240Z RCM-2 SAR
PASS), TROPICAL CYCLONE (TC) 06S WEAKENED SLIGHTLY DUE TO AN INCREASE 
IN NORTH-NORTHWESTERLY VERTICAL WIND SHEAR (VWS) EVIDENT IN THE 
ANIMATED WATER VAPOR RGB IMAGERY. HOWEVER, ANIMATED ENHANCED INFRARED 
(EIR) SATELLITE IMAGERY NOW DEPICTS A QUICKLY RE-DEVELOPING EYE WITH 
OUTFLOW BEGINNING TO EXPAND AGAIN OVER THE WESTERN SEMICIRCLE. 
MICROWAVE IMAGERY HAS BEEN EXTREMELY SPARSE, HOWEVER A 261604Z MHS 89 
GHZ MICROWAVE IMAGE REVEALS A COMPACT 70 NM DIAMETER CONVECTIVE CORE 
WITH A BREAK IN THE EYEWALL OVER THE NORTHEAST QUADRANT. THE INITIAL 
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE EIR IMAGERY AND 
THE MHS IMAGE. THE INITIAL INTENSITY OF 105 KTS IS ASSESSED WITH 
MEDIUM CONFIDENCE BASED ON THE HIGH END OF THE SUBJECTIVE DVORAK 
ESTIMATES RANGING FROM 90 TO 102 KNOTS.

INITIAL WIND RADII BASIS: SAR DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T5.0 - 90 KTS
   DEMS: T5.5 - 102 KTS
   CIMSS SATCON: 95 KTS AT 261605Z
   CIMSS ADT: 107 KTS AT 261500Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 06S IS FORECASTED TO TRACK WEST-SOUTHWESTWARD 
THROUGH TAU 48 ALONG THE NORTHERN PERIPHERY OF THE STR. AFTER TAU 48, 
TC 06S WILL TURN SOUTHWESTWARD TO SOUTH-SOUTHWESTWARD AS IT ROUNDS THE 
WESTERN PERIPHERY OF THE STR. ALTHOUGH THE SYSTEM EXPERIENCED A BRIEF 
WEAKENING TREND, IT IS EXPECTED TO REINTENSIFY TO 120 KNOTS WITHIN THE 
NEXT 36 HOURS. AFTER TAU 36, THE SYSTEM WILL GRADUALLY WEAKEN DUE TO 
COOLING SEA SURFACE TEMPERATURES AND DRY AIR ENTRAINMENT IN THE UPPER-
LEVELS. AFTER TAU 72, TC 06S WILL RECURVE AND INTERACT WITH STRONG 
SUBTROPICAL WESTERLIES WITH HIGH VWS (25 TO 55 KNOTS) AND COOL SST (23 
TO 25 C), WHICH WILL LEAD TO A RAPID WEAKENING TREND THROUGH TAU 120.  

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODEL
GUIDANCE IS IN TIGHT AGREEMENT THROUGH TAU 72 WITH A 45 NM CROSS-TRACK 
SPREAD IN SOLUTIONS AT TAU 72. AFTER TAU 72, THERE ARE SIGNIFICANT 
ALONG-TRACK DIFFERENCES BETWEEN THE DETERMINISTIC MODELS WITH GALWEM 
AND UKMET INDICATING MUCH FASTER TRACK SPEEDS WHILE GFS, NAVGEM AND 
THE ECMWF ENSEMBLE MEAN INDICATE SLOWER TRACK SPEEDS. THE 260600Z 
ECMWF ENSEMBLE AND THE 261200Z GFS ENSEMBLE SHOW A SIMILAR ALONG-TRACK 
SPREAD. THE JTWC INTENSITY FORECAST IS IN CLOSE AGREEMENT WITH THE 
INTENSITY CONSENSUS (ICNW), JUST BELOW HAFS-A, WHICH PEAKS AT 130 
KNOTS AT TAU 36.     

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