WDXS32 PGTW 222100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06S (ANGGREK) WARNING 
NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.6S 91.4E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 1164 NM EAST-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS TROPICAL
CYCLONE ANGGREK IS STRUGGLING. THE CONVECTIVE BANDS ARE BECOMING
FURTHER SEPARATED DUE TO DRY AIR ENTRAINMENT AND CONVECTION HAS
SHARPLY WANED OVER THE SOUTHERN HALF OF THE SYSTEM. UPWELLING AS A
RESULT OF THE SLOW MOVEMENT OF THE SYSTEM IS ALSO WORKING
AGAINST IT. THE JTWC DVORAK ASSESSMENT HAS ALSO FALLEN TO 2.0/3.0 AT 
FIX TIME. THE POSITION AND INTENSITY  ASSESSMENTS ARE BASED PRIMARILY 
ON THE A 221552Z ASCAT PASS. ANIMATED WATER VAPOR IMAGERY SHOWS 
SUBSTANTIAL SUPPRESSION OF OUTFLOW OVER THE WESTERN AND SOUTHERN 
QUADRANTS AND DECENT OUTFLOW OVER THE NORTHEAST QUADRANT. ALONG TRACK 
SEA SURFACE TEMPERATURES ARE FAVORABLE FOR A NEW SURGE IN DEVELOPMENT 
SHOULD THE SYSTEM MANAGE TO GET MOVING.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA FROM A 221552Z ASCAT. 

CURRENT STEERING MECHANISM: THE SYSTEM IS BOBBLING IN A WEAK
STEERING ENVIRONMENT IN A COL BETWEEN THE NEAR EQUATORIAL RIDGE AND
THE SUBTROPICAL RIDGE. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T3.0 - 45 KTS
   APRF: T3.0 - 45 KTS
   CIMSS ADT: 51 KTS AT 221730Z

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

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: TROPICAL CYCLONE ANGGREK WILL DRIFT VERY SLOWLY
ALONG A SOUTHWESTERLY BEARING OVER THE NEXT TWO DAYS AND STEADILY
INTENSIFY IN A LOW SHEAR ENVIRONMENT. AFTER 241800Z THE SUBTROPICAL
RIDGE WILL RETRACT, ALLOWING THE SYSTEM TO MOVE POLEWARD MORE
RAPIDLY THUS EASING THE CONSTRAINT OF UPWELLING. THE SYSTEM IS 
EXPECTED TO PEAK IN INTENSITY NEAR THAT TIME BEFORE PLUNGING OCEAN 
HEAT CONTENT AND DRY AIR ENTRAINMENT WEAKEN THE SYSTEM. IT IS STILL
EXPECTED TO MAINTAIN TYPHOON STRENGTH UNTIL THE VERY END OF THE
FORECAST PERIOD. 

MODEL DISCUSSION: TRACK GUIDANCE IS UNANIMOUS ON THE SLOW
SOUTHWESTERLY TRACK THROUGH THE FIRST 48 HOURS, THEN THE ALONG
TRACK SPREAD INCREASES AS THE SYSTEM ENCOUNTERS THE SEASONAL 
SOUTHEASTERLIES AND GETS SHOVED BACK TOWARDS THE EQUATOR. THE JTWC 
FORECAST STAYS NEAR CONSENSUS WITH SLIGHT FAVOR SHOWN TOWARD THE 
ECMWF ENSEMBLE. THE INTENSITY GUIDANCE IS GROUND IN THE STATISTICAL 
DYNAMICAL (SHIPS) GUIDANCE BUT GOES SHARPLY ABOVE THAT DURING THE 36 
THROUGH 60 HOUR PERIOD DUE TO INPUT FROM THE HAFS-A COUPLED MODEL. 

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