WDPN32 PGTW 011500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W (KONG-REY)      
WARNING NR 031//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.5N 123.2E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 366 NM WEST-SOUTHWEST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 27 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS INDICATED IN ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY,
TROPICAL STORM (TS) 23W IS RAPIDLY GAINING FRONTAL CHARACTERISTICS, 
WITH A WEAK COLD FRONT EXTENDING SOUTHWARD FROM THE CENTER AND A WARM 
FRONT EXTENDING EAST-NORTHEASTWARD. FORTUNATELY, BOTH EIR IMAGERY AND 
ANIMATED RADAR IMAGERY CONTINUE TO SHOW A DEFINED LOW-LEVEL CIRCULATION 
CENTER, WHICH SUPPORTS THE INITIAL POSITION WITH MEDIUM CONFIDENCE. THE 
SYSTEM HAS MERGED INTO AN AREA OF EXTENSIVE PRECIPITATION THAT EXTENDS 
INTO WESTERN JAPAN AND THE SOUTHERN KOREAN PENINSULA. THE INITIAL 
INTENSITY OF 45 KTS IS HEDGED BELOW AGENCY SUBJECTIVE DVORAK ESTIMATES 
BASED ON THE CIMSS OBJECTIVE INTENSITY ESTIMATES RANGING FROM 38 TO 47 
KNOTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   CIMSS ADT: 47 KTS AT 011200Z
   CIMSS AIDT: 43 KTS AT 011200Z
   CIMSS DPRINT: 39 KTS AT 011200Z
   CIMSS DMINT: 38 KTS AT 010955Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS 23W WILL RECURVE AROUND THE NORTHWEST PERIPHERY 
OF THE STR OVER THE NEXT 12 HOURS WHILE QUICKLY TRANSITIONING TO AN 
EXTRA-TROPICAL COLD-CORE LOW ON THE FRONTAL BOUNDARY. THE SYSTEM IS 
EXPECTED TO MAINTAIN A TIGHT PRESSURE GRADIENT AS IT TRACKS ACROSS 
WESTERN JAPAN, WITH AN EXTENSIVE REGION OF HEAVY PRECIPITATION 
PERSISTING ALONG THE FRONTAL BOUNDARY ENHANCED BY AN UPPER-LEVEL 
SHORTWAVE TROUGH EMBEDDED IN THE MIDLATITUDE WESTERLIES. AFTER TAU 12, 
THE SYSTEM WILL ACCELERATE EASTWARD UNDER A STRONG JET ENTRENCHED OVER 
JAPAN. DUE TO THE STRONG GRADIENT ASSOCIATED WITH THE FRONT, GALE-FORCE 
WINDS ARE EXPECTED TO CONTINUE THROUGH THE FORECAST PERIOD.  

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN FAIR AGREEMENT 
THROUGH THE FORECAST PERIOD WITH AN 80NM TO 160NM CROSS-TRACK SPREAD 
FROM TAU 12 TO TAU 24. THE 010600Z GFS ENSEMBLE (GEFS) SHOWS A SIMILAR 
SPREAD OF ENSEMBLE SOLUTIONS, WITH THE BULK OF THE SOLUTIONS AT MINIMAL 
TS STRENGTH AFTER TAU 24. RELIABLE INTENSITY GUIDANCE SUPPORTS THE JTWC 
INTENSITY FORECAST AND STEADY WEAKENING THROUGH TAU 36. HOWEVER, 
GUIDANCE SUPPORTS A 40-45 KNOT INTENSITY NEAR TAU 12 WHEN THE SYSTEM 
MAKES LANDFALL ALONG THE WESTERN COAST OF KYUSHU.   

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