WDPS31 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 16P (SIXTEEN) WARNING 
NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.0S 164.7E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 95 NM SOUTHWEST OF NOUMEA, NEW CALEDONIA
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 16P WITH AN ILL-DEFINED, PARTIALLY EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC). A 111006Z ASCAT-B IMAGE REVEALED THE
VERY DISORGANIZED NATURE OF THE CIRCULATION WITH 30-35 KNOT WINDS.
ENVIRONMENTAL ANALYSIS INDICATES THAT 16P IS IN A MARGINALLY
UNFAVORABLE ENVIRONMENT CHARACTERIZED BY STRONG POLEWARD OUTFLOW
ALOFT AND WARM SEA SURFACE TEMPERATURES OFFSET BY HIGH (35-40 KTS)
VERTICAL WIND SHEAR. THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON THE MENTIONED ASCAT IMAGE AND ANIMATED EIR
IMAGERY. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE ASCAT IMAGE, AGENCY DVORAK ESTIMATES, AND
OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF NEAR EQUATORIAL
RIDGING TO THE NORTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T1.5 - 25 KTS
   PHFO: T2.5 - 35 KTS
   CIMSS ADT: 39 KTS AT 111200Z
   CIMSS AIDT: 37 KTS AT 111200Z
   CIMSS DPRINT: 38 KTSAT 111200Z
   CIMSS DMINT: 35 KTS AT 111302Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 35-40 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE TRACK HAS BEEN SLOWED
SIGNIFICANTLY COMPARED TO THE PREVIOUS FORECAST.

FORECAST DISCUSSION: 16P IS FORECAST TO CONTINUE TRACKING
EAST-SOUTHEASTWARD THROUGH TAU 12. AFTER TAU 12, THE SYSTEM WILL
SHALLOW OUT FURTHER DUE TO THE DRY AIR AND HIGH VERTICAL WINDS
SHEAR, THIS WILL CAUSE THE STEERING MECHANISM TO SWITCH TO A
SHALLOWER STEERING LEVEL. AS A RESULT, THE SYSTEM WILL BE NEARLY
QUASI-STATIONARY AFTER TAU 24. SUBTROPICAL TRANSITION IS CURRENTLY
FORECAST TO BEGIN AROUND TAU 36 WITH COMPLETION BY TAU 48 DUE TO
THE VERY SHALLOW SYSTEM AND VERY HIGH VERTICAL WIND SHEAR (OVER 50
KTS). REGARDING INTENSITY, 16P IS FORECAST TO MAINTAIN INTENSITY
DUE PRIMARILY TO THE STRONG POLEWARD OUTFLOW.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN VERY POOR
AGREEMENT REGARDING THE TRACK OF 16P, ESPECIALLY AFTER TAU 24. MANY
MODELS BECOME ERRATIC AS THE SYSTEM SHALLOWS OUT. THEREFORE, THE
JTWC TRACK FORECAST IS PLACED WITH LOW CONFIDENCE. INTENSITY
GUIDANCE IS IN BETTER AGREEMENT, WITH MODELS OVERALL SUGGESTING
MINIMAL INTENSIFICATION OVER THE NEXT 24 HOURS WITH GRADUAL
WEAKENING THEREAFTER. 

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