WDPS31 PGTW 051500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06P (SIX) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.0S 148.0W
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 129 NM NORTHEAST OF PAPEETE, TAHITI
   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 06P WITH A HIGHLY COMPACT LOW-LEVEL CIRCULATION CENTER
(LLCC) AND DEEP CONVECTION OBSCURING THE CENTER. ANIMATED WATER
VAPOR IMAGERY REVEALS DEFINED CIRRUS FILAMENTS EXTENDING OUTWARD IN
THE POLEWARD DIRECTION INTO THE UPPER-LEVEL JET TO THE SOUTH. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE
ANIMATED EIR IMAGERY. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND CIMSS
OBJECTIVE INTENSITY ESTIMATES LISTED BELOW. ENVIRONMENTAL ANALYSIS
INDICATES THAT 06P IS IN A MARGINALLY FAVORABLE ENVIRONMENT
CHARACTERIZED BY STRONG POLEWARD OUTFLOW ALOFT, LOW (10-15 KTS)
VERTICAL WIND SHEAR, DRY AIR TO THE SOUTHWEST, AND WARM (27-28 C)
SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE POSITIONED TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   PHFO: T2.0 - 30 KTS
   CIMSS ADT: 39 KTS AT 051210Z
   CIMSS AIDT: 35 KTS AT 051210Z
   CIMSS D-MINT: 31 KTS AT 051049Z
   CIMSS D-PRINT: 35 KTS AT 051210Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR TO THE SOUTHWEST

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: 06P IS FORECAST TO TRACK SOUTH-SOUTHEASTWARD,
ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE TO THE EAST
THROUGHOUT THE SHORT FORECAST PERIOD. TRACK SPEEDS ARE EXPECTED TO
INCREASE AS THE SYSTEM CONTINUES TO APPROACH THE UPPER-LEVEL JET
STREAK TO THE SOUTH. THE SYSTEM IS FORECAST TO MAINTAIN AN
INTENSITY OF AROUND 40 KTS THROUGH TAU 24 AS EXTREME POLEWARD
OUTFLOW FIGHTS AGAINST INCREASING SHEAR AND COOLING SEA SURFACE
TEMPERATURES. AROUND TAU 24, 06P IS FORECAST TO BE WITHIN AN AREA
OF 30 KTS OR HIGHER WESTERLY VERTICAL WIND SHEAR AND SEA SURFACE
TEMPERATURES COOLER THAN 26 C. ADDITIONALLY, SIGNIFICANT AMOUNTS OF
DRY AIR ENTRAINMENT FROM THE WEST WILL SHALLOW OUT THE VORTEX. AS A
RESULT, THE SYSTEM IS ANTICIPATED TO COMPLETE SUBTROPICAL
TRANSITION NEAR TAU 24 AS IT RACES OFF TO THE SOUTH-SOUTHEAST.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN VERY GOOD
AGREEMENT WITH A CROSS-TRACK SPREAD OF 65 NM AND MINIMAL
ALONG-TRACK SPREAD AT TAU 24. THE JTWC TRACK FORECAST IS PLACED
CLOSE TO THE CONSENSUS WITH HIGH CONFIDENCE. INTENSITY GUIDANCE
GENERALLY AGREES ON A STEADY INTENSITY THROUGH TAU 24. GFS SHOWS
SLIGHT INTENSIFICATION TO AROUND 45 KTS THROUGH TAU 12 WHILE THE
REMAINDER OF GUIDANCE HOVERS AROUND 40 KTS. THE JTWC INTENSITY
FORECAST IS ALSO PLACED CLOSE TO THE CONSENSUS WITH HIGH
CONFIDENCE.

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