WDPN32 PGTW 091500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN) WARNING NR 
054//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 32.4N 128.8E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 62 NM SOUTHWEST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
OVERALL ASYMMETRIC SYSTEM WITH A MASS OF DEEP CONVECTION
LARGELY ON THE NORTHERN SEMICIRCLE WITH A PARTIALLY EXPOSED LOW
LEVEL CIRCULATION CENTER (LLCC). ADDITIONALLY, WATER VAPOR IMAGERY
SHOWS STRONG POLEWARD OUTFLOW STREAMING TOWARD THE NORTHEAST AWAY
FROM THE SYSTEMS CENTER. AN EARLIER 090849Z SSMIS 89 GHZ IMAGE
DEPICTS A DEEP CONVECTIVE BAND OVER THE NORTHERN QUADRANT, WRAPPING
INTO THE CORE OF THE SYSTEM. THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON ANIMATED INFRARED IMAGERY ALONG WITH THE
AFOREMENTIONED SSMIS MICROWAVE IMAGE AND WITHIN CLOSE PROXIMITY TO
AGENCY DVORAK POSITION FIXES. THE INITIAL INTENSITY OF 60 KNOTS IS
ASSESSED WITH HIGH CONFIDENCE BASED ON A 090924Z SAR PASS WHICH
SHOWS 55-60 KNOTS ON THE NORTHWESTERN SEMICIRCLE. IN ADDITION TO
SUBJECTIVE DVORAK CURRENT INTENSITY'S FROM PGTW AND KNES ALONG WITH
OBJECTIVE DVORAK INTENSITY ESTIMATES.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: STRONG POLEWARD OUTFLOW


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: THE OVERALL TRACK OF TS 06W REMAINS CONSISTENT
WITH THE PREVIOUS FORECAST, AS THE SYSTEM TRANSITS QUICKLY
NORTHWESTWARD WITHIN ENVIRONMENTAL CONDITIONS WHICH REMAIN
MARGINALLY FAVORABLE WITH GOOD EQUATORWARD AND POLEWARD OUTFLOW AND
LOW VERTICAL WIND SHEAR (VWS), WARM SEA SURFACE TEMPERATURES (SST)
OFFSET BY DRY AIR ENTRAINMENT. LANDFALL IS EXPECTED TO THE WEST OF
BUSAN AFTER TAU 12, INTERACTION WITH THE KOREAN PENINSULA WILL LEAD
TO DETERIORATION TO 35 KNOTS BY TAU 36 AND THEN TO EVENTUAL
DISSIPATION BY TAU 72.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE REMAINS IN VERY
GOOD AGREEMENT WITH ONLY A 97NM CROSS-TRACK SPREAD BETWEEN
CONSENSUS MEMBERS THROUGH TAU 72. THEREFORE, THERE IS HIGH
CONFIDENCE IN THE JTWC TRACK FORECAST. THERE IS MEDIUM CONFIDENCE
IN THE JTWC INTENSITY FORECAST WITH INTENSITY GUIDANCE SHOWING A
STEADY DECREASING TREND AFTER TAU 12 WITH SOME POTENTIAL
VARIABILITY IN THE INTENSITY DUE TO LAND INTERACTION.


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