WDPN33 PGTW 130900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (TORAJI) WARNING NR 
017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.6N 115.3E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 119 NM SOUTH-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS
COLLAPSING DEEP-LAYER CONVECTION OVER THE CENTER OF TROPICAL STORM
(TS) 26W. LOW-LEVEL CLOUD BANDING IS REVEALED IN THE CENTER AND
SOUTHERN PERIMETER OF THE CIRCULATION DUE TO HIGH (15-29KT)
SOUTHERLY VERTICAL WIND SHEAR (VWS). WATER VAPOR IMAGERY REVEALS
STRONG DIVERGENT POLEWARD OUTFLOW DUE TO CLOSE PROXIMITY TO AN
UPPER-LEVEL JET MAXIMUM. A 130510Z 37GHZ GCOM W1 AMSR2 MICROWAVE
IMAGE REVEALS THE WEAKENED NATURE OF TS 26W, WHICH HAS BROADENED
OVER THE LAST SIX HOURS WHILE PASSING OVER COOL WATERS BETWEEN
25-26C. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON THE AFOREMENTIONED ANIMATED EIR AND EXTRAPOLATION FROM THE
130510Z AMSR2 IMAGE. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED
WITH LOW CONFIDENCE DUE TO THE SWIFTLY DEGRADING STRUCTURE 
ALONGSIDE THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE (STR) TO THE SOUTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   CIMSS SATCON: 42 KTS AT 130254Z
   CIMSS ADT: 32 KTS AT 130530Z
   CIMSS AIDT: 33 KTS AT 130530Z
   CIMSS D-MINT: 37 KTS AT 130512Z
   CIMSS D-PRINT: 42 KTS AT 130530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY UNFAVORABLE
   VWS: 15-20 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: THE STEERING INFLUENCE ON 26W WILL TRANSITION
FROM DEEP-LAYER TO MID- AND LOW-LEVEL. AS A RESULT, THE SYSTEM WILL
HOOK WESTWARD OVER THE NEXT 24 HOURS WHILE WEAKENING AND BECOMING
DRIVEN SOUTHWESTWARD BY THE NORTHEAST MONSOON. THE GALES OF
NOVEMBER WILL CONTINUE TO ERODE THE STRUCTURE OF TS 26W AS
SUBSIDENT COOL AIR FROM A COLD BURST ORIGINATING IN THE
NORTHEASTERN SOUTH CHINA SEA ENTRAINS INTO THE SYSTEM AND DRIES THE
ENVIRONMENT DURING THE FIRST 12 HOURS OF THE FORECAST. THE SYSTEM
WILL ENTER A TONGUE OF COOL WATER BELOW 25C AFTER TAU 24, WHICH
COMBINED WITH HIGH VERTICAL WIND SHEAR WILL INCREASE THE RATE OF
WEAKENING, ULTIMATELY DISSIPATING BETWEEN TAU 36-48.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE AGREES THAT TS 26W
WILL HOOK WESTWARD BEFORE BECOMING INFLUENCED BY LOW-LEVEL
SOUTHWESTERLY FLOW, BUT THE DEGREE OF HOW SHARPLY THE SYSTEM HOOKS
SOUTH AND TRACK SPEED VARIES LARGELY DEPENDING ON HOW QUICKLY THE
MODEL SOLUTIONS HANDLE THE RATE OF WEAKENING. WITH ONLY A 135NM
CROSS-TRACK SPREAD, HAFS-A DEPARTS THE PATTERN TAKING THE SYSTEM
NEARLY DUE WEST ON THE NORTHERN PERIPHERY OF THE STR, WHILE ALL
OTHER MODEL SOLUTIONS CURVE SOUTHWARD. THE JTWC INTENSITY GUIDANCE
IS IN STRONG AGREEMENT THAT THE SYSTEM WILL WEAKEN BETWEEN TAU
36-48, AND AS A RESULT THE JTWC INTENSITY FORECAST LIES CLOSELY TO
THE MULTI-MODEL CONSENSUS MEAN.

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