WDPN31 PGTW 130900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (NARI)         
WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.6N 143.0E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 492 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A WELL-DEFINED, 
FULLY EXPOSED LOW-LEVEL CIRCULATION, WITH FLARING DEEP CONVECTION 
DISPLACED OVER THE EASTERN SEMICIRCLE. THE INITIAL POSITION IS PLACED 
WITH HIGH CONFIDENCE BASED ON THE MSI. A 130608Z GMI 37GHZ MICROWAVE 
IMAGE REVEALS SHALLOW BANDING WRAPPING INTO A WELL-DEFINED LOW-LEVEL 
CIRCULATION CENTER, WHICH ALSO SUPPORTS THE INITIAL POSITION. A 
130005Z ASCAT-B PARTIAL IMAGE CONTINUES TO SHOW A SWATH OF 30-35 KNOT 
WINDS OVER THE EASTERN SEMICIRCLE, WHICH SUPPORTS THE INITIAL 
INTENSITY WITH MEDIUM CONFIDENCE. ENVIRONMENTAL CONDITIONS ARE 
MARGINALLY FAVORABLE DUE TO THE PRESENCE OF A TUTT CELL TO THE 
NORTHWEST AND UPPER-LEVEL CONVERGENCE OVER THE WESTERN SEMICIRCLE OF 
THE SYSTEM.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: LOW- TO MID-LEVEL SUBTROPICAL RIDGE
POSITIONED TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 42 KTS AT 130401Z
   CIMSS ADT: 33 KTS AT 130520Z
   CIMSS AIDT: 35 KTS AT 130520Z
   CIMSS D-MINT: 35 KTS AT 130608Z
   CIMSS D-PRINT: 36 KTS AT 130630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

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

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 FORECAST TO TRACK
NORTHWARD THROUGH TAU 36 ALONG THE WESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE (STR). TS 06W IS FORECAST TO CONSOLIDATE QUICKLY
DUE TO THE RAPIDLY IMPROVING POLEWARD OUTFLOW, AND WILL PEAK AT 50
KNOTS BY TAU 24. THE AFOREMENTIONED TUTT CELL CURRENTLY HINDERING
DEVELOPMENT IS FORECAST TO FILL AND SHIFT POLEWARD OVER THE NEXT 12
HOURS AS WELL. AFTER TAU 24, THE SYSTEM WILL BEGIN TO WEAKEN DUE TO
COOLING SST TEMPERATURES. AFTER TAU 36, TS 06W WILL GRADUALLY
RECURVE AROUND THE NORTHWESTERN PERIPHERY OF THE STR AND WILL
UNDERGO EXTRATROPICAL TRANSITION WHILE ACCELERATING NORTHEASTWARD.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE REMAINS IN TIGHT
AGREEMENT, WITH A 55NM CROSS-TRACK SPREAD IN SOLUTIONS AT TAU 24.
GUIDANCE DIVERGES AFTER TAU 24, WITH INCREASING UNCERTAINTY IN THE
RECURVE TRACK AND TRACK SPEEDS. ENSEMBLE GUIDANCE HAS SHIFTED
SLIGHTLY EAST OVER THE PAST 24 HOURS, WITH THE MAJORITY OF
SOLUTIONS NOW EAST OF THE BOSO PENINSULA.   

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