WDPN32 PGTW 092100 
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN) WARNING NR 
055//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 33.7N 128.8E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 58 NM NORTHWEST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AND THE BAND PLAYS ON. AFTER A FIVE-DAY SWING THROUGH OKINAWA AND THE 
RYUKUS TROPICAL STORM KHANUN IS NOW ROCKING SASEBO AND CHINHAE ALONG 
ITS SUMMER TOUR THROUGH WPAC. SASEBO WINDS HAVE COME UP TO SUSTAINED 
SMALL CRAFT FORCE WITH GALE FORCE GUSTS. THE SYSTEM IS SHOWING A 
SLIGHT WOBBLE AND THE SLIGHTEST SIGNS OF DECAY DUE TO AND INTERACTION 
AS IT TREKS ACROSS THE TSUSHIMA STRAIT. ANIMATED WATER VAPOR IMAGERY 
SHOWS SPECTACULAR POLEWARD OUTFLOW AND A DIMINISHING EQUATORWARD 
CHANNEL. ALONG TRACK SEA SURFACE TEMPERATURES DECREASE ABOUT 2 
DEGREES C BUT REMAIN SUBSTANTIVE WHILE VERTICAL WIND SHEAR INCREASES 
SHARPLY NEAR THE SOUTH COAST OF PENINSULA. DEEP CONVECTION IS NOW 
CONFINED MOSTLY TO THE NORTHWEST QUADRANT BUT THE CORE REMAINS TIGHTLY 
WRAPPED. THERE IS, HOWEVER, A DEARTH OF CONVECTION IN THE CORE, WHICH 
ALLOWED FOR EASILY POSITIONING OF THE SYSTEM. THE INTENSITY ASSESSMENT 
IS BASED IN UNANIMOUS T3.5 FROM FOUR AGENCIES. DPRINT, DMINT, AND AIDT 
OBJECTIVE GUIDANCE IS 5 KNOTS HIGHER, BUT DUE TO FALLING DATA T FROM 
PGTW AND PLUNGING ADT RAW MEASUREMENTS, THE AGENCY CI ASSESSMENTS 
LOOK TO BE THE MOST ACCURATE.

INITIAL WIND RADII BASIS: PERSISTENCE FROM 090924Z SAR PASS. 

CURRENT STEERING MECHANISM: THE WESTERN FLANK OF THE SUBTROPICAL
RIDG.E 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 58 KTS AT 091530Z
   CIMSS ADT: 32 KTS AT 091740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

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: TROPICAL CYCLONE 06W WILL WEAKEN AS IT
APPROACHES LANDFALL TO THE WEST OF CHINHAE. VERTICAL WIND SHEAR AND
LAND INTERACTION WILL INITIATE THE FINAL DECLINE OF THE SYSTEM.
THERE IS ENOUGH ENERGY LEFT FOR THE SYSTEM TO REMAIN VIABLE WITH
GUSTY WINDS AND ABUNDANT PRECIPITATION AS IT MOVES THROUGH THE OSAN,
HUMPREYS, AND FINALLY SEOUL AREA. IT IS NOT EXPECTED TO GO BELOW
35 KNOTS UNTIL NORTH OF THE 38TH PARALLEL. THE SUBTROPICAL RIDGE WILL
CONTINUE FORCING THE SYSTEM TO THE WEST OF NORTH MAKING FOR A VERY
BRIEF RE-ENTRY INTO THE WEST SEA BEFORE FINALLY DISSIPATING OVER
THE CHINESE BORDER.  

MODEL DISCUSSION: BOTH TRACK AND INTENSITY GUIDANCE IS TIGHTER THAN
USUAL. THE JTWC TRACK FORECAST STAYS NEAR THE MULTI-MODEL
CONSENSUS WHILE THE INTENSITY FORECAST IS A LITTLE MORE AGGRESSIVE
ON THE OVERLAND DECLINE OVER THAN THE MEAN, BUT ALIGNS WITH THE
TREND.   

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