WDPS31 PGTW 231500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 28P (TWENTYEIGHT) 
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.1S 162.9E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 216 NM WEST-NORTHWEST OF NOUMEA, NEW
CALEDONIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 28P PASSING JUST TO THE WEST OF NEW CALEDONIA WITH DEEP
CONVECTION SLIGHTLY OFFSET TO THE SOUTH OF THE LOW-LEVEL
CIRCULATION CENTER (LLCC). STRONG NORTHWESTERLY SHEAR CAUSED BY AN
UPPER-LEVEL TROUGH TO THE WEST IS THE CULPRIT FOR THE ENHANCED
SHEAR OVER THE TOP OF THE SYSTEM. A 231121Z METOP-C ASCAT PASS
REVEALED A COMPACT CORE OF 40-45 KNOT WINDS WITH THE NORTHWESTERN
QUADRANT CONTAINING THE WEAKEST WINDS. THE INITIAL POSITION,
INTENSITY, AND WIND RADII ARE ALL PLACED WITH HIGH CONFIDENCE BASED
ON THE ASCAT PASS. ENVIRONMENTAL ANALYSIS INDICATES THAT 28P IS IN
A MARGINALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY STRONG OUTFLOW
ALOFT AND WARM (27-28 C) SEA SURFACE TEMPERATURES OFFSET BY DRY AIR
ENTRAINMENT AND HIGH (25-30 KTS) NORTHWESTERLY VERTICAL WIND SHEAR.

INITIAL WIND RADII BASIS: 231121Z METOP-C ASCAT SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) POSITIONED SOUTH OF FIJI.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   PHFO: T3.0 - 45 KTS
   CIMSS SATCON: 47 KTS AT 230930Z
   CIMSS ADT: 51 KTS AT 231200Z
   CIMSS AIDT: 42 KTS AT 231200Z
   CIMSS D-MINT: 35 KTS AT 230814Z
   CIMSS D-PRINT: 45 KTS AT 231200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 25-30 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE WEST

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 28P IS FORECAST TO CONTINUE TRACKING
SOUTHWARD, ALONG THE WESTERN PERIPHERY OF THE STR THROUGH TAU 24.
ROBUST POLEWARD OUTFLOW INTO A JET MAX TO THE SOUTH WILL ALLOW FOR
28P TO MARGINALLY INTENSIFY OVER THE NEXT 12 HOURS EVEN THOUGH
NORTHERLY SHEAR AND DRY AIR ENTRAINMENT WILL ONLY WORSEN. THE
SYSTEM IS EXPECTED TO STAY NORTH OF THE 26 C SST ISOTHERM, WHICH
LINES UP WITH THE 25TH LATITUDE, UP UNTIL TAU 12. COOLING SEA
SURFACE TEMPERATURES, VERY STRONG SHEAR, AND DRY AIR ENTRAINMENT
WILL CEASE FURTHER INTENSIFICATION AFTER TAU 12. SUBTROPICAL
TRANSITION IS FORECAST TO BEGIN AT TAU 12 WITH COMPLETION OCCURRING
AT TAU 24 AS SHEAR INCREASES TO OVER 50 KTS AND SEA SURFACE
TEMPERATURES DROP TO AROUND 23-24 C. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGHOUT THE SHORT FORECAST PERIOD WITH A CROSS-TRACK
SPREAD OF 70 NM AT TAU 24. AS A RESULT, THE JTWC TRACK FORECAST IS
PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.
INTENSITY GUIDANCE AGREES ON SLIGHT INTENSIFICATION THROUGH TAU 12,
TO ABOUT 50 KTS, FOLLOWED BY A STEADY INTENSITY THROUGH TAU 24 WITH
LITTLE VARIATION BETWEEN MODELS. THE JTWC INTENSITY FORECAST IS
ALSO PLACED NEAR THE CONSENSUS WITH HIGH CONFIDENCE. 

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