WDXS31 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01S (ANCHA) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.0S 73.8E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 304 NM SOUTH-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM
HAS BEGUN TO UNRAVEL AND ELONGATE AS THE SOUTHERN PORTIONS HAVE
BECOME EXPOSED TO HIGH VWS AS EVIDENCED BY EROSION ALONG THE
NORTHERN PARTS AND EXTENSIVE TRANSVERSE BANDING IN THE CIRRI CANOPY
ALONG THE WESTERN AND SOUTHERN PERIPHERIES. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON A RAGGED BUT DEFINED
MICROWAVE LLC FEATURE IN THE 1635Z AMSU-B IMAGE. THE INITIAL
INTENSITY OF 45KTS IS ALSO PLACED WITH MEDIUM CONFIDENCE BASED ON
OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES THAT
DEPICT THE WEAKENING TREND AND REFLECTS THE 6-HR CONVECTIVE DECAY
EVIDENT IN THE EIR LOOP.

INITIAL WIND RADII BASIS: PERSISTENCE.

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   FMEE: T3.5 - 55 KTS
   CIMSS SATCON: 51 KTS AT 021435Z
   CIMSS ADT: 37 KTS AT 021800Z
   CIMSS DPRNT: 45 KTS AT 021800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 15-20 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC ANCHA WILL CONTINUE ON A SOUTHWESTWARD
TRACK UNDER THE STEERING STR TO THE SOUTHEAST. THE UNFAVORABLE
ENVIRONMENT WILL GET WORSE AS VWS INCREASES AND SSTS BECOME COLDER,
LEADING TO DISSIPATION BY TAU 36. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH A
GRADUAL AND EVEN SPREAD TO JUST 126NM BY TAU 36, LENDING HIGH
CONFIDENCE TO THE JTWC TRACK AND INTENSITY FORECASTS. 

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