WDPN31 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (NARI)         
WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.6N 143.2E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 332 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 30 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A RAPIDLY 
CONSOLIDATING LOW-LEVEL CIRCULATION (LLC), WITH DEEP CONVECTION 
BUILDING OVER THE LLC AND WRAPPING AROUND THE NORTHWESTERN QUADRANT. 
ALTHOUGH ANTICIPATED, THE SYSTEM'S ORGANIZATION HAS IMPROVED 
SIGNIFICANTLY IN A SHORT PERIOD. THE UW-CIMSS UPPER-LEVEL WINDS 
INDICATE THAT THE TUTT CELL HAS FILLED AND WEAKENED ALLOWING UPPER-
LEVEL OUTFLOW TO EXPAND QUICKLY OVER THE NORTHWESTERN QUADRANT. A 
131211Z ASCAT-C BULLSEYE IMAGE SHOWS A SWATH OF 40-50 KNOT WINDS OVER 
THE EASTERN SEMICIRCLE, A MAJOR IMPROVEMENT AS COMPARED TO PREVIOUS 
ASCAT IMAGERY. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE 
BASED ON THE EIR IMAGERY AND ASCAT DATA. THE INITIAL INTENSITY OF 50 
KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE ASCAT DATA. 
SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES ARE TOO LOW AT THIS TIME.

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: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 36 KTS AT 130938Z
   CIMSS ADT: 33 KTS AT 131130Z
   CIMSS AIDT: 36 KTS AT 131130Z
   CIMSS D-PRINT: 38 KTS AT 131130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: TROPICAL STORM HAS CONSOLIDATED QUICKLY 
OVER THE PAST SIX HOURS WITH SOLID EVIDENCE FOR THE 50 KNOT INTENSITY 
ASSESSMENT. THE INTENSITY FORECAST HAS BEEN ADJUSTED TO REFLECT THIS 
RECENT TREND.

FORECAST DISCUSSION: TROPICAL STORM (TS) 06W IS FORECAST TO TRACK
QUICKLY NORTHWARD THROUGH TAU 24 ALONG THE WESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE (STR). AS ANTICIPATED, TS 06W HAS CONSOLIDATED
QUICKLY DUE TO THE RAPIDLY IMPROVING POLEWARD OUTFLOW AND WEAKENING
TUTT CELL AND IS FORECAST TO PEAK AT 55 KNOTS BY TAU 12. THERE IS
SOME UNCERTAINTY IN THE PEAK INTENSITY, WITH POTENTIAL FOR SLIGHTLY
HIGHER PEAK INTENSITY VALUES OVER THE NEXT 12 HOURS. AFTER TAU 12,
THE SYSTEM WILL BEGIN TO STEADILY WEAKEN DUE TO COOLING SST
TEMPERATURES. AFTER TAU 24, TS 06W WILL GRADUALLY RECURVE AROUND
THE NORTHWESTERN PERIPHERY OF THE STR AND WILL UNDERGO EXTRATROPICAL 
TRANSITION (ETT) WHILE ACCELERATING NORTH-NORTHEASTWARD. TS 06W WILL 
COMPLETE ETT BY TAU 36 AS IT BECOMES EMBEDDED IN THE MIDLATITUDE 
WESTERLIES POLEWARD OF THE STR.
 
MODEL DISCUSSION: WITH THE EXCEPTION OF AFUM, DETERMINISTIC MODEL
GUIDANCE REMAINS IN TIGHT AGREEMENT, WITH A 50NM CROSS-TRACK SPREAD
IN SOLUTIONS AT TAU 12. 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//
NNNN