WDPN31 PGTW 140900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (NARI) WARNING NR 
014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 36.8N 142.6E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 167 NM EAST-NORTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 27 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC), WITH NO ASSOCIATED
DEEP CONVECTION. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE 
BASED ON THE MSI AND RADAR IMAGERY. A 140524Z GMI 37GHZ COLOR 
COMPOSITE MICROWAVE IMAGE REVEALS A WELL-ORGANIZED LLCC, WITH
TIGHTLY CURVED BANDING WRAPPING INTO A DEFINED CENTER. ENVIRONMENTAL 
CONDITIONS ARE MARGINAL PRIMARILY DUE TO COOLING SST (24-25C) 
TEMPERATURES. THE INITIAL INTENSITY IS ASSESSED AT 45 KNOTS BASED ON 
THE 140406Z AMSR2 WINDSPEED IMAGE, WHICH ALSO SHOWS THE GALE FORCE 
WINDS CONFINED TO THE EASTERN SEMICIRCLE. 

INITIAL WIND RADII BASIS: AMSR2 WINDSPEED IMAGE

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   CIMSS SATCON: 52 KTS AT 140600Z
   CIMSS ADT: 30 KTS AT 140530Z
   CIMSS AIDT: 37 KTS AT 140530Z
   CIMSS D-MINT: 35 KTS AT 140523Z
   CIMSS D-PRINT: 32 KTS AT 140600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: 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 38N) AND ENCOUNTERS STRONG VERTICAL 
WIND SHEAR.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE REMAINS IN TIGHT
AGREEMENT, WITH A 38NM CROSS-TRACK SPREAD IN SOLUTIONS AT TAU 12
AND AN 88NM CROSS-TRACK SPREAD AT TAU 24. THE 140000Z 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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