WDPN33 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (TORAJI) WARNING NR 
018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.8N 115.1E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 58 NM EAST-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY REVEALS THAT
TROPICAL STORM (TS) 26W HAS TRACKED NORTHWARD OVER THE LAST SIX
HOURS ON AN EXTENSION OF A RIDGE OVER THE NORTHERN PHILIPPINE SEA
INTO THE SOUTH CHINA SEA. THE SYSTEM CONTINUES TO STRUGGLE
AND IS BECOMING SHALLOW IN AN ENVIRONMENT WITH HIGH (15-20KT) 
VERTICAL WIND SHEAR AND COOL (25-26C) SEA SURFACE TEMPERATURES. THE 
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE 
AFOREMENTIONED ANIMATED EIR REVEALING THE CENTER OF THE CIRCULATION. 
THE INITIAL INTENSITY OF 45 KT IS ASSESSED WITH MEDIUM CONFIDENCE 
BASED ON PERSISTENCE FROM AN EARLIER 130510Z GCOM W1 AMSR2 WIND SPEED 
IMAGE REVEALING 45 KT WIND SPEEDS THROUGHOUT THE CIRCULATION.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: A WESTWARD EXTENSION OF THE SUBTROPICAL
RIDGE TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T2.5 - 35 KTS
   DEMS: T2.0 - 30 KTS
   CIMSS SATCON: 48 KTS AT 131028Z
   CIMSS ADT: 34 KTS AT 131130Z
   CIMSS AIDT: 35 KTS AT 131130Z
   CIMSS D-MINT: 43 KTS AT 131027Z
   CIMSS D-PRINT: 40 KTS AT 131200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: SINCE THE LAST WARNING, THE SYSTEM
HAS TRACKED SIGNIFICANTLY FARTHER NORTH THAN PREVIOUSLY FORECASTED.
DUE TO THE CHANGE IN TRACK, THE CONFIDENCE IN THE MODEL GUIDANCE,
WHICH CONTINUES TO INDICATE A WESTWARD AND SOUTHWESTWARD TRACK, IS
LOWER.

FORECAST DISCUSSION: TS 26W WILL TRACK WESTWARD OVER THE NEXT 24
HOURS, PASSING SOUTH OF HONG KONG AS THE STEERING MECHANISM
TRANSFERS FROM THE SUBTROPICAL RIDGE (STR) TO THE EAST OF THE SYSTEM 
TO A DEEP-LAYER RIDGE TO THE SOUTHWEST. AFTER TAU 24, THE SYSTEM WILL 
BE STEERED ON THE MID- TO LOW-LEVEL NORTHEASTERLY FLOW. THE SYSTEM
WILL CONTINUOUSLY WEAKEN OVER THE REMAINDER OF THE FORECAST PERIOD
WHILE IN AN ENVIRONMENT OF HIGH VERTICAL WIND SHEAR AND COOL SEA
SURFACE TEMPERATURES. SUBSIDENT DRY AIR WILL CAUSE THE ENVIRONMENT
TO FURTHER WEAKEN TO DISSIPATION BY THE END OF THE FORECAST.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE STRONGLY AGREES THAT
THE SYSTEM WILL CURVE TO A SOUTHWESTWARD TRACK, HOWEVER THE CURRENT
STATE OF THE ENVIRONMENT IS NOT REFLECTIVE OF THE ANTICIPATED TRACK
MOTION. OVER THE LAST SIX HOURS, THE SYSTEM HAS STALLED ITS
WEAKENING TREND AND HAS TRACKED NORTHWARD, DESPITE A HIGH CONFIDENCE 
IN THE PREVIOUS MODEL GUIDANCE. REGARDLESS OF TRACK, THE INTENSITY 
GUIDANCE, WHICH HAS A HIGH CONFIDENCE IN THE WEAKENING TREND, LEADS 
TO A SLIGHTLY HIGHER CONFIDENCE AS THE ENVIRONMENT REMAINS 
UNFAVORABLE. IF THE SYSTEM WERE TO CONTINUE TO DEFY MODEL GUIDANCE 
AND TRACK NORTHWARD, THERE IS A POTENTIAL THAT THE SYSTEM MAY MAKE 
LANDFALL AND DISSIPATE EARLIER THAN FORECAST.

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