WDPN32 PGTW 072100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN) WARNING NR 
047//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 28.5N 131.1E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 285 NM SOUTH-SOUTHEAST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 01 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS DEEP
CONVECTIVE BANDS FEEDING INTO A BROAD, EXPOSED CENTER WITH MULTIPLE
MESOVORTICES ROTATING CYCLONICALLY AROUND A CENTROID. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE CENTROID
THAT APPEARS TO HAVE SIGNIFICANTLY SLOWED DOWN, SUPPORTED BY A
BROAD CLUSTER OF RADAR AND AGENCY FIXES. THE INITIAL INTENSITY IS
ALSO PLACED WITH MEDIUM CONFIDENCE BASED ON THE HIGH END OF AGENCY
AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE SLIGHT 6-HR
WEAKENING. ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH MODERATE
EQUATORWARD OUTFLOW, LOW VWS, AND WARM SST OFFSET BY SUBSIDENCE
ALONG THE NORTHWEST SIDE AND DRY AIR ENTRAINMENT IN THE LOW LEVELS.

INITIAL WIND RADII BASIS: PERSISTENCE.

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.5 - 55 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 39 KTS AT 071730Z
   CIMSS D-PRINT: 48 KTS AT 071800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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 IS EXPECTED TO SLOWLY DRIFT GENERALLY
NORTH-NORTHWESTWARD TOWARD SOUTH KOREA AS THE STEERING STR BUILDS,
MAKING LANDFALL WEST OF BUSAN AROUND TAU 54, TRACK OVER SEOUL
AROUND TAU 72, BEFORE TURNING NORTH-NORTHEASTWARD INTO NORTH KOREA
THEN NORTHEASTERN CHINA. THE ENVIRONMENT WILL SLIGHTLY IMPROVE AS
SST WARMS AROUND THE ISLAND OF KYUSHU, JAPAN, THEN WITH INCREASING
POLEWARD OUTFLOW, FUELING A SLIGHT INTENSIFICATION TO A PEAK OF
65KTS AROUND TAU 36. AFTERWARD INTERACTION WITH THE KOREAN
PENINSULA WILL LEAD TO GRADUAL DETERIORATION TO 4OKTS IN THE SEOUL
AREA THEN TO EVENTUAL DISSIPATION BY TAU 120 AFTER THE SYSTEM
CROSSES INTO CHINA. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT UP
TO TAU 72 WITH AN EVEN SPREAD TO 346NM, LENDING MEDIUM CONFIDENCE
IN THIS PORTION OF THE JTWC TRACK FORECAST. AFTERWARD, THE MODELS
BECOME MORE SPREAD OUT AND ERRATIC, LENDING LOW CONFIDENCE IN THE
EXTENDED PORTION OF THE JTWC FORECAST. 

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