WDPS31 PGTW 212100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 16P (SIXTEEN) WARNING 
NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.1S 164.5E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 89 NM WEST OF NOUMEA, NEW CALEDONIA
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 19 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
THE STRUCTURE OF TROPICAL CYCLONE (TC) 16P HAS LOOSENED SOMEWHAT
WITH A SLIGHTLY TILTED, BROADENING, AND CLOUD FILLED LOW-LEVEL
CIRCULATION CENTER (LLCC). CONVECTIVE ACTIVITY IS DISPLACED TO THE
SOUTHWEST AS DEPICTED BY ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON ANIMATED SHORTWAVE INFRARED (SWIR) AND VISUAL IMAGERY OF THE
LLCC FEATURE CONSISTENT WITH AN EARLIER 211402Z AMSR2 PASS. THE
INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON WINDSPEED DATA DERIVED FROM THE AFOREMENTIONED AMSR2 PASS
AS WELL AS SURFACE OBSERVATIONS FROM NEW CALEDONIA.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED NEAR FIJI. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   PHFO: T3.0 - 45 KTS
   CIMSS SATCON: 44 KTS AT 211600Z
   CIMSS ADT: 33 KTS AT 211930Z
   CIMSS AIDT: 38 KTS AT 211930Z
   CIMSS D-MINT: 32 KTS AT 211434Z
   CIMSS D-PRINT: 31 KTS AT 211930Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: WEAK POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 (TC) 16P WILL CONTINUE TO
TRACK EAST-SOUTHEASTWARD UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE 
TO THE NORTH. THE SYSTEM WILL SLOWLY WEAKEN THROUGHOUT THE FORECAST
PERIOD AS VERTICAL WIND SHEAR PERSISTS AND SURROUNDING DRIER AIR
ENTRAINS INTO THE SYSTEM. DISSIPATION OF TC 16P IS EXPECTED BY TAU
36 WITH 30 KT MAXIMUM WIND SPEEDS. 

MODEL DISCUSSION: CROSS TRACK SPREAD AMONGST THE CONSENSUS MODELS
IS UNDER 100 NM THROUGHOUT THE FORECAST PERIOD, WITH GFS AT THE
NORTHERN END OF THE GUIDANCE ENVELOPE AND COAMPS-TC AND THE ECMWF
ENSEMBLE MEAN BRACKETING THE SOUTHERN SIDE OF THE GUIDANCE. THE JTWC
FORECAST TRACK IS PLACED CLOSE TO THE MULTI MODEL CONSENSUS WITH
HIGH CONFIDENCE. INTENSITY SPREAD AMONGST THE MODEL GUIDANCE IS
UNDER 20 KTS WITH THE MAJORITY HOVERING AT 30-35 KT MAXIMUM WIND
SPEEDS FOR THE REMAINDER OF THE FORECAST PERIOD. THE JTWC OFFICIAL
FORECAST REFLECTS INTENSITIES CLOSE TO THE MULTI MODEL CONSENSUS AND 
PREVIOUS FORECAST WITH HIGH CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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