WDPN31 PGTW 231500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 17W 
(TALAS) WARNING NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 33.0N 136.0E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 199 NM SOUTHWEST OF CAMP FUJI
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A FULLY
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) SHEARED FROM THE MAIN
BODY OF CONVECTION. ALL OF THE CONVECTIVE STRUCTURE IS NORTHEAST OF
THE LLCC OVER MAINLAND HONSHU, LEAVING THE LLCC A MERE 35NM
SOUTHEAST OF KUSHIMOTO, JAPAN. AN OLDER 230841Z SSMIS 91GHZ
MICROWAVE IMAGE INDICATES THE CONVECTION OVER THE KANTO PLAIN
REGION. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON EIR LOOP AND EXTRAPOLATION FROM THE PREVIOUSLY MENTIONED
MICROWAVE IMAGE. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE AND HELD WITH A MAJORITY OF MULTIPLE AGENCY
DVORAK INTENSITY ESTIMATES. THE STRONG POLEWARD OUTFLOW REMAINS THE
ONLY ENVIRONMENTAL CONDITION FAVORABLE, WITH ALL OTHER CONDITIONS
HINDERING THE SYSTEM, INCLUDING STRONG VWS AND COOLER SSTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   CIMSS SATCON: 44 KTS AT 230842Z
   CIMSS ADT: 30 KTS AT 231150Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TD 17W IS SHRINKING IN INTENSITY BASED ON THE
OVERALL UNFAVORABLE ENVIRONMENT, WITH VERTICAL WIND SHEAR (VWS)
INHIBITING ANY DEVELOPMENT AND THE COOLER SSTS. THE SYSTEM IS
FORECAST TO CONTINUE ON A NORTHEAST TRACK UNTIL REACHING LANDFALL
NEAR EITHER TOYOHASHI OR HAMAMATSU, JAPAN, BY TAU 12. THE SYSTEM
WILL BEGIN DISSIPATING ONCE LAND INTERACTION OCCURS AND THE
APPROACHING UPPER-LEVEL TROUGH NORTHWEST OF THE SYSTEM. THIS
INTERACTION BETWEEN THE SYSTEM AND THE UPPER-LEVEL FEATURE WILL
INCREASE VERTICAL WIND SHEAR (VWS), DISRUPTING THE SYSTEMS TROPICAL
CONVECTIVE STRUCTURE. BY TAU 36, 17W WILL COMPLETELY DISSIPATE OVER
WATER, IF NOT SLIGHTLY SOONER.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT
AGREEMENT EXCLUDING NVGM AND JGSM, WHICH REMAIN THE SOLE RIGHT
OUTLIERS OF THE MODEL ENVELOPE. THE CROSS-TRACK SPREAD IS ONLY 35NM
UP TO TAU 24 EXCLUDING NVGM AND JGSM. DUE TO THE WEAK LLC, THE
MODELS ARE STRUGGLING TO RESOLVE THE EXIT OF THE WEAK CIRCULATION
BACK OUT OVER WATER. THUS, THE JTWC OFFICIAL TRACK FORECAST IS
PLACED WITH MEDIUM CONFIDENCE. THE JTWC INITIAL INTENSITY IS CLOSE
TO THE MULTI-MODEL CONSENSUS WITH MEDIUM CONFIDENCE THROUGHOUT THE
FORECAST PERIOD.

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