WDPN32 PGTW 010900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W (KONG-REY)      
WARNING NR 030//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 28.3N 121.4E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 516 NM WEST-SOUTHWEST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 18 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS INDICATED IN ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI),
TROPICAL STORM (TS) 23W IS SKIRTING THE EASTERN COAST OF CHINA AND
CONTINUING TO WEAKEN STEADILY AS IT INTERACTS WITH A STRONG FRONTAL
ZONE AND BEGINS EXTRA-TROPICAL TRANSITION (ETT). MSI REVEALS A
RAGGED, DEFINED LOW-LEVEL CIRCULATION CENTER, WITH THE SYSTEM'S
CONVECTIVE CORE ESSENTIALLY MERGING INTO AN AREA OF EXTENSIVE
PRECIPITATION THAT EXTENDS INTO WESTERN JAPAN AND THE SOUTHERN
KOREAN PENINSULA. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON A 010447Z AMSR2 89GHZ COLOR COMPOSITE MICROWAVE
IMAGE, WHICH SHOWS A WELL-DEFINED MICROWAVE EYE FEATURE AND
FRAGMENTED CONVECTIVE BANDING. THE INITIAL INTENSITY OF 50 KTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON A 010447Z AMSR2 WINDSPEED
IMAGE, WHICH INDICATES A SWATH OF 40-45 KNOT WINDS SOUTHEAST OF THE
CENTER, AGENCY SUBJECTIVE DVORAK ESTIMATES AND CIMSS OBJECTIVE
INTENSITY ESTIMATES RANGING FROM 41 TO 58 KNOTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 56 KTS AT 010600Z
   CIMSS ADT: 57 KTS AT 010530Z
   CIMSS AIDT: 51 KTS AT 010530Z
   CIMSS DPRINT: 41 KTS AT 010530Z
   CIMSS DMINT: 48 KTS AT 010530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: INTERACTION WITH LAND

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 TO 24 HOURS WHILE QUICKLY
TRANSITIONING TO AN EXTRA-TROPICAL COLD-CORE LOW ON THE FRONTAL
BOUNDARY BY TAU 24. THE SYSTEM IS EXPECTED TO MAINTAIN A TIGHT
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 24, 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 FAIRLY GOOD
AGREEMENT THROUGH THE FORECAST PERIOD WITH A 90NM TO 130NM
CROSS-TRACK SPREAD FROM TAU 24 TO TAU 36. THE 010000Z 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 18 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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