WDXS31 PGTW 012100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 15S (ANIKA) 
WARNING NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.2S 121.6E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 39 NM WEST-SOUTHWEST OF BROOME, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS BANDING
ON THE SOUTHERN SIDE WITH LOW LEVEL CLOUD LINES WRAPING INTO THE
ASSESED CENTER OF CIRCULATION. AT ANALYSIS TIME, ABOM RADAR
INDICATED A WEAK RADAR EYE ABOUT 20NM NORTHWEST OF BIDYADANGA,
AUSTRALIA, FOR WHICH THE INITIAL POSITION IS BASED. THE INITIAL
INTENSITY OF 35 KTS IS HEDGED SLIGHTY HIGHER THAN AGENCY DVORAK
CURRENT INTENSITY ESTIMATES WHICH MAY BE UNDERESTIMATING THE
SYSTEM'S INTENSITY DUE TO ITS PROXIMITY TO LAND.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   APRF: T2.0 - 30 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: WEAK POLEWARD
   OTHER FACTORS: INTERACTION WITH AUSTRAILAN COASTLINE

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: AVAILABLE METEOROLOGICAL DATA
SUPPORTS THE REGENERATION OF TC 15S, THEREFORE, JTWC HAS RESUMED
WARNINGS.

FORECAST DISCUSSION: TC 15S IS EXPECTED TO CONTINUE TO TRACK
SOUTHWESTWARD UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE TO THE
SOUTHEAST. BY TAU 12, THE SYSTEM WILL BEGIN TO TURN SOUTHWARD AS A
MID-LATITUDE TROUGH WEAKENS THE SUBTROPICAL RIDGE CAUSING THE
SYSTEM TO MOVE OVER LAND SHORTLY AFTERWARDS. TC 15S WILL PEAK AT 45
KTS INTENSITY SOMETIME BETWEEN TAU 12 AND TAU 24 AND WILL GRADUALLY
WEAKEN OVERLAND DUE TO THE FLAT GEOGRAPHY OF NORTHWESTERN
AUSTRALIA. THE SYSTEM IS EXPECTED TO WEAKEN TO 30 KTS BY TAU 48.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT IN
REGARDS TO BOTH FORECAST TRACK AND FORECAST INTENSITY WITH MODELS
DEPICTING A SOUTHWARD THEN SOUTHEASTWARD TRACK AND A PEAK INTENSITY
OF ABOUT 45 KNOTS PRIOR TO LANDFALL BEFORE TAU 24 WITH GRADUAL
WEAKENING AFTERWARDS.

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