WDPN32 PGTW 082100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN) WARNING NR 
051//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.5N 129.8E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 156 NM SOUTH OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS DEEP
CONVECTIVE BANDS WRAPPING INTO A LARGE, EXPOSED LOW LEVEL
CIRCULATION (LLC) THAT HAS RELATIVELY BECOME SMALLER OVER THE PAST
12HRS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON 
THE LLC FEATURE IN THE EIR LOOP AND ALSO ON A COMPOSITE RADAR LOOP.
THE INITIAL INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON
THE OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES
AND REFLECTS THE SLIGHT 6-HR WRAP IMPROVEMENT. ANALYSIS INDICATES A
MARGINALLY FAVORABLE ENVIRONMENT WITH GOOD VENTILATION AND LOW VWS
ALOFT, AND WARM SST OFFSET BY SUBSIDENCE ALONG THE NORTHEAST SIDE
AND DRY AIR ENTRAINMENT IN THE LOWER LEVELS.

INITIAL WIND RADII BASIS: PERSISTENCE.

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 32 KTS AT 081730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: MODERATE POLEWARD OUTFLOW. 

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 06W WILL CONTINUE TO TRACK NORTHWESTWARD
TOWARD THE KOREAN PENINSULA VIA THE KOREAN STRAIT UNDER THE
STEERING STR, MAKING LANDFALL WEST OF BUSAN AROUND TAU 30, THEN
TRACK JUST TO THE WEST OF SEOUL BY TAU 48 BEFORE CROSSING INTO
NORTH KOREA. THE MARGINALLY FAVORABLE ENVIRONMENT WILL PROMOTE A
SLIGHT INTENSIFICATION TO A PEAK OF 60KTS AT TAUS 12-24. 
AFTERWARD, INTERACTION WITH THE RUGGED TERRAIN OF THE KOREAN
PENINSULA COMBINED WITH RAPIDLY INCREASING VWS WILL LEAD TO RAPID
DETERIORATION TO 35KTS NEAR SEOUL THEN TO EVENTUAL DISSIPATION BY
TAU 72 AFTER THE SYSTEM CROSSES INTO NORTH KOREA. 


MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT,
LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. DUE TO THE
VARIABILITY OF LAND PASSAGE, THERE IS ONLY OVERALL MEDIUM
CONFIDENCE IN THE INTENSITY FORECAST. 

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