WDXS32 PGTW 292100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06S (ANGGREK)
WARNING NR 030//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.3S 70.8E
   INITIAL INTENSITY: 105 KTS
   GEOGRAPHIC REFERENCE: 832 NM EAST-SOUTHEAST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 45 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TC 06S
(ANGGREK) WITH A DECREASINGLY ORGANIZED, YET COMPACT EYE-STRUCTURE
TRACKING SOUTHWARD RELATIVE TO THE POSITION SIX HOURS AGO.
THE CYCLONE CONTINUES TO MAINTAIN OBSERVABLE CONVECTIVE BANDING
WRAPPED COMPLETELY AROUND THE LOW-LEVEL CIRCULATION CENTER AND AN
OBSERVABLE 14NM EYE-FEATURE; HOWEVER, THE OVERALL STORM STRUCTURE
HAS BECOME NOTICEABLY ELONGATED IN NATURE WITH ASSOCIATED
TRANSVERSE BANDING BEING INFLUENCED BY STRONG WESTERLIES TO THE
SOUTH. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
A COLLAPSING EYE OBSERVABLE IN A 291800Z GOES-IO EIR SATELLITE IMAGE. 
THE INITIAL INTENSITY IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE 
PGTW DVORAK ESTIMATE OF T5.5 (102TS) AND THE CONTINUED ORGANIZED 
OVERALL STRUCTURE, WHILE CIMSS OBJECTIVE INTENSITY ESTIMATES ARE 
ASSESSED BETWEEN 92-115 KTS. THE INTENSITY IS CONSISTENT WITH 
CONTINUED SUSTAINMENT OF CONVECTIVE BANDING AROUND THE CIRCULATION 
CENTER, AN ONGOING OBSERVABLE EYE-STRUCTURE, AND STRONG POLEWARD 
OUTFLOW.

INITIAL WIND RADII BASIS: SAR DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   FMEE: T5.5 - 102 KTS
   FIMP: T5.5 - 102 KTS
   KNES: T6.0 - 115 KTS
   CIMSS ADT: 112 KTS AT 291900Z
   CIMSS AIDT: 107 KTS AT 291900Z
   CIMSS DPRINT: 92 KTS AT 291700Z
   CIMSS SATCON: 117 KTS AT 291830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 25-30 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

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 06S (ANGGREK) IS FORECAST TO CONTINUE
TRACKING SOUTHWARD, AND EVENTUALLY SOUTHEASTWARD THROUGH TAU 12 AS
THE CYCLONE IS PREDOMINANTLY STEERED BY THE WELL-ESTABLISHED
STEERING RIDGE DIRECTLY TO THE EAST AND RECEDES IN RESPONSE TO AN
EASTWARD PROGRESSING MID-LATITUDE LONGWAVE TROUGH. THE ENVIRONMENT IS 
EXPECTED TO BECOME INCREASINGLY UNFAVORABLE AS THE TROPICAL CYCLONE 
CONTINUES GENERALLY TO THE SOUTHEAST THROUGH TAU 36, AS VERTICAL WIND 
SHEAR (VWS) ASSOCIATED WITH THE WESTERLIES SIGNIFICANTLY INCREASES TO 
GREATER THAN 40 KTS BY TAU 12 AND SEA SURFACE TEMPERATURES DECREASE 
TO BELOW 26C DURING THE SAME FORECAST PERIOD. AT TAU 36 TC 06S IS 
EXPECTED TO BEGIN THE EXTRA-TROPICAL TRANSITION (ETT) AND CONTINUE 
EASTWARD ALONG THE WESTERLIES, EVENTUALLY BECOMING COMPLETELY EXTRA-
TROPICAL BY TAU 48. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE CONTINUES TO REMAIN IN
RELATIVELY TIGHT AGREEMENT THROUGH TAU 24, WITH A GRADUAL CROSS-TRACK 
SPREAD TO 115NM BY TAU 48, LENDING HIGH CONFIDENCE TO THE JTWC 
FORECAST. INTENSITY GUIDANCE ASSOCIATED WITH TC 06S REMAINS AT A 
MEDIUM CONFIDENCE AS THE ETT IS EXPECTED TO OCCUR QUICKLY. 
STATISTICAL-DYNAMICAL GUIDANCE REFLECTS COMPETING AND UNFAVORABLE 
ENVIRONMENTAL CONDITIONS NEGATIVELY IMPACT ANY CHANCE FOR FURTHER 
DEVELOPMENT INTO TAU 48, WHILE STRONG VWS, COOLER SST, AND DRY AIR 
WILL RAPIDLY WEAKEN TC 06S. 

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