WDXS32 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06S (ANGGREK)
WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.0S 92.6E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 253 NM WEST OF COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 06S (ANGGREK) HAVING A PARTIALLY EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC) WITH NEARLY ALL DEEP CONVECTION APPEARING
IN THE WESTERN SEMICIRCLE. MODERATE EQUATORWARD OUTFLOW CONTINUES
TO PROVIDE GOOD OUTFLOW ALOFT WITH CIRRUS FILAMENTS OBSERVED
PROPAGATING NORTH-NORTHWESTWARD IN THE UPPER LAYERS. EVIDENCE OF
DRY AIR ENTRAINMENT ALONG THE EASTERN PERIPHERY IS OBSERVED THROUGH
A GENERAL CLEARING OF UPPER AND MID LEVEL CLOUDS, WHICH WAS ALSO
ANTICIPATED BY MULTIPLE NUMERICAL MODELS. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON ANIMATED EIR IMAGERY SHOWING
A PARTIALLY EXPOSED LLCC AND EXTRAPOLATION OF A 201540 METOP-B
SCATTEROMETRY IMAGE. THE INITIAL INTENSITY OF 70 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON EXTRAPOLATION OF A 201224Z RCM-1
SYNTHETIC APERTURE RADAR IMAGE CAPTURING UP TO 74KTS, AS WELL AS
THE SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: SAR DATA

CURRENT STEERING MECHANISM: STR SOUTHWEST OF TC 06S

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T4.0 - 65 KTS
   APRF: T3.5 - 55 KTS
   CIMSS SATCON: 70 KTS AT 201500Z
   CIMSS ADT: 82 KTS AT 201800Z
   CIMSS AIDT: 70 KTS AT 201800Z
   

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 IS FORECAST TO BEGIN A WESTWARD TURN
AND GRADUALLY COME TO A WEST-SOUTHWESTWARD TRACK BY TAU 72. WITH
SLOW TRACK SPEEDS (1 TO 3 KTS) IN THE FORECAST, UPWELLING OF COOLER
OCEAN WATERS (POSSIBLY AS LOW AS 21C ACCORDING TO COUPLED
ATMOSPHERE-OCEAN MODELS) AND DRY AIR ENTRAINMENT FROM THE A
RELATIVELY DRY AIR MASS TO THE SOUTHEAST ARE ANTICIPATED TO IMPACT
THE SYSTEMS INTENSITY. AFTER TAU 72, AND ON A GENERAL SOUTHWESTWARD
TRACK, THE TC IS ANTICIPATED TO SLIGHTLY INTENSIFY AS IN NAVIGATES
AWAY FROM THE HINDERING ENVIRONMENTAL FACTORS MENTIONED WITH A
SLIGHTLY HIGHER TRACK SPEED (4 TO 5 KTS) THROUGH TAU 120.

MODEL DISCUSSION: GLOBAL NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT THAT TC 06S WILL TRACK NORTHWESTWARD TO TAU 12 AND SLOWLY
TRACK WESTWARD UNTIL TAU 36. OVER THIS INTERVAL, INTENSITY GUIDANCE
SUGGESTS THE TC INTENSITY WILL GRADUALLY FALL.  AFTER TAU 36,
GUIDANCE SUGGESTS THE TC WILL TRACK WEST-SOUTHWEST TO SOUTHWEST
UNTIL TAU 72. INTENSITY GUIDANCE DIVERGES AT THIS POINT, WITH GFS
AND STATISTICAL-DYNAMICAL GUIDANCE INTENSIFYING THE SYSTEM AND
OTHER MEMBERS OF THE INTENSITY CONSENSUS MAINTAINING OR SHOWING A
DOWNWARD TREND IN INTENSITY. A CROSS-TRACK SPREAD AT TAU 72 OF
30NM, WITH THE EXCEPTION OF MOGREPS, YIELDS A FORECAST CONFIDENCE OF 
MEDIUM.  HOWEVER, AN ALONG-TRACK SPREAD OF APPROXIMATELY 500NM BY TAU 
120 YIELDS MUCH UNCERTAINTY IN TRACK SPEED AND CONTRIBUTES TO A 
FORECAST CONFIDENCE FROM TAU 72 TO TAU 120 OF LOW.

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