WDPN31 PGTW 141500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (NARI)         
WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 39.7N 142.5E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 73 NM SOUTHEAST OF MISAWA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 29 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A WELL-
DEFINED EXPOSED LOW-LEVEL CIRCULATION, WITH NO ASSOCIATED DEEP
CONVECTION. A 141153Z ASCAT-C BULLSEYE IMAGE SHOWS A DEFINED
CENTER, WITH 35-40 KNOT WINDS OVER THE EASTERN QUADRANT. THIS IMAGE
SUPPORTS THE INITIAL INTENSITY, INITIAL POSITION AND INITIAL
34-KNOT WIND RADII WITH HIGH CONFIDENCE. THE SYSTEM IS PRODUCING
SUSTAINED EASTERLY FLOW (10-20 KNOTS) INTO NORTHERN HONSHU,
ADVECTING FOG, STRATUS AND DRIZZLE OVER MISAWA AIR BASE.
ENVIRONMENTAL CONDITIONS ARE MARGINAL PRIMARILY DUE TO COOLING SST
(20-22C) TEMPERATURES.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST.  

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 46 KTS AT 140915Z
   CIMSS ADT: 25 KTS AT 141130Z
   CIMSS AIDT: 37 KTS AT 141130Z
   CIMSS D-PRINT: 30 KTS AT 141200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 20-22 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL STORM (TS) 06W IS TRACKING QUICKLY
NORTHWARD ALONG THE WESTERN PERIPHERY OF THE STR THROUGH TAU 12.
AFTER TAU 12, THE SYSTEM WILL ROUND THE NORTHWEST PERIPHERY OF THE
STR AND WILL COMPLETE EXTRA-TROPICAL TRANSITION (ETT) BY TAU 24 AS
IT TRACKS UNDER THE MIDLATITUDE WESTERLIES, JUST SOUTH OF THE JET.
TS 06W IS FORECAST TO WEAKEN STEADILY AS IT TRACKS OVER COLD SST
VALUES (LESS THAN 20C NORTH OF 40N) AND ENCOUNTERS STRONG VERTICAL
WIND SHEAR.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE REMAINS IN TIGHT
AGREEMENT, WITH A 37NM CROSS-TRACK SPREAD IN SOLUTIONS AT TAU 12
AND AN 91NM CROSS-TRACK SPREAD AT TAU 24. THE 140600Z ECENS AND
GEFS RUNS ARE ALSO IN TIGHT AGREEMENT THROUGH TAU 24 LENDING HIGH
CONFIDENCE TO THE JTWC TRACK FORECAST.

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