WDPS33 PGTW 161500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 15P (FIFTEEN) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.3S 160.6W
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 70 NM NORTHWEST OF RAROTONGA
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 19 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS AN
EXTREMELY ELONGATED SYSTEM WITH DISORGANIZED CONVECTION THAT SPANS
460NM NW-SE EMBEDDED IN THE SOUTHERN HEMISPHERE MONSOON TROUGH JUST
SOUTH OF THE SOUTH PACIFIC CONVERGENCE ZONE. THE INITIAL POSITION
AND INTENSITY ARE PLACED WITH HIGH CONFIDENCE BASED ON THE 160847Z
ASCAT PASS SHOWING AN OBLONG CIRCULATION WITH A PATCH OF 40-KNOT
WIND BARBS 40NM TO THE NORTHEAST. ANALYSIS INDICATES A MARGINAL
ENVIRONMENT WITH WARM SST AND STRONG DUAL-OUTFLOW OFFSET BY
MODERATE TO STRONG VWS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   NFFN: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG DUAL-CHANNEL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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 15P WILL CONTINUE ON ITS CURRENT TRACK
UNDER THE STR TO THE EAST. THE MARGINAL CONDITIONS WILL MAINTAIN
ITS CURRENT INTENSITY UP TO TAU 12 BEFORE GRADUALLY WEAKENING DUE
TO INCREASING VWS AND COOLING SST. CONCURRENTLY BY TAU 12, THE
SYSTEM WILL COMMENCE EXTRA-TROPICAL TRANSITION AND BY TAU 24 WILL
BECOME A GALE-FORCE COLD-CORE LOW WITH AN EXPANSIVE WIND FIELD. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH
AN EVEN SPREAD TO 65NM BY TAU 24, LENDING HIGH CONFIDENCE TO THE
JTWC TRACK FORECAST. 

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