WDPN32 PGTW 260900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (HIGOS) WARNING NR 
016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 28.4N 134.6E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 489 NM SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 35 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM (TS) 08W (HIGOS) AS A HIGHLY SHEARED, SHALLOW VORTEX TRACKING
VERY QUICKLY NORTH-NORTHEASTWARD. THE LOW-LEVEL CIRCULATION CENTER
(LLCC) IS NOW FULLY EXPOSED AND IS COMPLETELY DEVOID OF DEEP
CONVECTION. THE MINIMAL CONVECTION THE SYSTEM HAS MANAGED TO
SUSTAIN IS SHEARED FAR TO THE SOUTHEAST. ENVIRONMENTAL ANALYSIS
INDICATES TS 08W IS LOCATED IN A HOSTILE ENVIRONMENT, CHARACTERIZED
BY HIGH (25-30 KTS) VERTICAL WIND SHEAR (VWS), COOL (25-26 C) SEA
SURFACE TEMPERATURES (SST), POOR OUTFLOW, AND A RELATIVELY DRIER
SURROUNDING ENVIRONMENT. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE FULLY EXPOSED LLCC IN ANIMATED MSI. THE
INITIAL INTENSITY OF 45 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED
ON THE CIMSS OBJECTIVE INTENSITY ESTIMATES AND AGENCY DVORAK FIXES
LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 37 KTS AT 260700Z
   CIMSS ADT: 41 KTS AT 260700Z
   CIMSS AIDT: 42 KTS AT 260700Z
   CIMSS D-MINT: 37 KTS AT 260451Z
   CIMSS D-PRINT: 32 KTS AT 260700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 25-30 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: WEAK EQUATORWARD
   OTHER FACTORS: RELATIVELY DRIER SURROUNDING ENVIRONMENT

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 08W IS FORECAST TO ACCELERATE
NORTH-NORTHEASTWARD FOR THE NEXT 12 HOURS WHILE IT FINISHES
ROUNDING THE STR CENTERED TO ITS EAST. BY TAU 12, HIGOS IS EXPECTED
TO TRACK MORE NORTHEASTWARD AS IT BECOMES FULLY EMBEDDED IN THE
WESTERLIES. NEAR TAU 12, 08W IS FORECAST TO BEGIN EXTRATROPICAL
TRANSITION (ETT) AS IT TRACKS FARTHER POLEWARD AND INTERACTS WITH
THE POLAR FRONT JET AND THE BAROCLINIC ZONE. ETT IS ANTICIPATED TO
BE COMPLETE NO LATER THAN TAU 24. REGARDING INTENSITY, HIGOS IS
FORECAST TO GRADUALLY WEAKEN THROUGH THE FORECAST PERIOD; HOWEVER,
THE POSSIBILITY FOR GREATER WEAKENING IS POSSIBLE AS THE
FAST-MOVING SYSTEM TRACKS DEEPER INTO THE HOSTILE ENVIRONMENT. 


MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG
AGREEMENT THROUGH TAU 12, WITH NEGLIGIBLE DIFFERENCES BETWEEN
MEMBERS. AS A RESULT, THE JTWC TRACK FORECAST IS LAID WITH HIGH
CONFIDENCE. RELIABLE INTENSITY AIDS ARE ALSO IN STRONG AGREEMENT
THAT 08W WILL GENERALLY MAINTAIN INTENSITY THROUGH TAU 12; HOWEVER,
A FEW MODELS DEPICT A MORE DRASTIC WEAKENING TREND BETWEEN TAU
12-24. THE DISCREPANCY IS NOT SIGNIFICANT ENOUGH TO CAUSE
DEGRADATION TO THE JTWC INTENSITY FORECAST, WHICH IS ASSESSED WITH
HIGH CONFIDENCE.

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