WDPN31 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (YUN-YEUNG) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.6N 133.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 291 NM EAST OF KADENA AB, OKINAWA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A MEDIUM-SIZED
CONSOLIDATING SYSTEM WITH THE MAIN CONVECTION TRAILING A PARTIALLY
EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLCC.
THE INITIAL INTENSITY OF 35KTS IS BASED WITH HIGH CONFIDENCE ON THE
HIGH END OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE
6-HR IMPROVEMENT. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH
WARM SST AND MODERATE OUTFLOW OFFSET BY MODERATE VWS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST.


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 34 KTS AT 052330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS YUN-YEUNG WILL CONTINUE ON ITS CURRENT
TRACK TOWARD JAPAN UNDER THE STEERING INFLUENCE OF THE STR TO THE
EAST, PASSING APPROXIMATELY 38NM TO THE SOUTH OF YOKOSUKA AROUND
080800Z. BY TAU 72, TS 12W WILL CREST THE STR AXIS THEN DRIFT
NORTHEASTWARD. THE FAVORABLE CONDITIONS WILL FUEL A STEADY
INTENSIFICATION TO A PEAK OF 50KTS BY TAU 36 AS IT DRIFTS INTO THE
WARM KUROSHIO CURRENT. AFTERWARD, LAND INTERACTION AND INCREASING
VWS WILL GRADUALLY ERODE THE CYCLONE DOWN TO 25KTS BY TAU 120.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT
WITH JGSM AND AFUM THAT ARE TRACKING THE VORTEX AT AN OBTUSE ANGLE
TOWARD THE SEA OF JAPAN. IN VIEW OF THIS, THERE IS OVERALL MEDIUM
CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID TO THE RIGHT OF
CONSENSUS TO OFFSET AFUM AND JGSM THAT ARE EXCESSIVELY PULLING IT
TO THE LEFT.   

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
NNNN