WDPN32 PGTW 261500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (HIGOS) WARNING NR 
017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 31.8N 136.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 277 NM SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 36 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) 08W (HIGOS) DISAPPEARING BENEATH THE WESTERLY MID-LEVEL
CLOUDS AND BECOMING NEARLY UN-TRACKABLE IN ANIMATED IMAGERY. THE
261009Z SSMIS MICROWAVE PASS REVEALS AN ELONGATED AND RELATIVELY
COMPACT SYSTEM COMPLETELY DEVOID OF DEEP CONVECTION. ENVIRONMENTAL 
ANALYSIS REVEALS A HOSTILE ENVIRONMENT CHARACTERIZED BY HIGH (30-35 
KTS) VERTICAL WINDS SHEAR (VWS), POOR OUTFLOW, AND MARGINAL (25-26 C)
SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS ASSESSED WITH LOW 
CONFIDENCE BASED ON EXTRAPOLATION FROM THE 261009Z SSMIS DATA. THE 
INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED 
ON THE AGGREGATION OF AGENCY DVORAK FIXES AND THE CIMSS INTENSITY 
ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: THE NORTHWESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE CENTERED TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 34 KTS AT 261230Z
   CIMSS AIDT: 40 KTS AT 261230Z
   CIMSS D-MINT: 30 KTS AT 261010Z
   CIMSS D-PRINT: 28 KTS AT 261230Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 30-35 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: WEAK POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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: TS 08W IS FORECAST TO CONTINUE ACCELERATING
NORTHEASTWARD FOR THE DURATION OF THE FORECAST PERIOD. 08W IS
ASSESSED TO BE UNDERGOING EXTRATROPICAL TRANSITION (ETT) -- IT IS
EMBEDDED DEEP UNDER THE UPPER-LEVEL WESTERLIES, EXHIBITING
TEMPERATURE ADVECTION, AND THE VERY SHALLOW VORTEX THAT REMAINS IS
BECOMING INCREASINGLY ELONGATED. ETT IS ANTICIPATED TO BE COMPLETE
NO LATER THAN TAU 24, BUT LIKELY WELL BEFORE. 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 PLACED WITH HIGH
CONFIDENCE. RELIABLE INTENSITY AIDS ARE ALSO IN STRONG AGREEMENT
THAT 08W WILL GENERALLY MAINTAIN INTENSITY THROUGH TAU 12; HOWEVER,
A FEW MODELS (GFS, HWRF, AND COAMPS-TC) DEPICT A BRIEF BUT
SIGNIFICANT INTENSIFICATION TREND BETWEEN TAU 0-12. DUE TO THE
CURRENT ENVIRONMENT, WHICH IS EXPECTED TO REMAIN HIGHLY UNFAVORABLE
AND FURTHER DETERIORATE AS 08W TRACKS POLEWARD, THIS
INTENSIFICATION SCENARIO IS CONSIDERED UNLIKELY AND IS NOT
SIGNIFICANT ENOUGH TO CAUSE DEGRADATION TO THE JTWC INTENSITY
FORECAST. THE JTWC INTENSITY FORECAST LIES VERY CLOSE TO THE HAFS-A
SOLUTION AND THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.

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