WDPN32 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN) WARNING NR 
053//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 31.5N 128.9E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 104 NM SOUTH-SOUTHWEST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTIVE BANDING WRAPPING INTO A BROAD EXPOSED CENTER THAT
CONTINUES TO BECOME SMALLER OVER THE PAST SIX HOURS. A 090500Z
AMSR2 89 GHZ MICROWAVE IMAGE DEPICTS A FORMATIVE CONVECTIVE BAND
OVER THE NORTHERN SEMICIRCLE WITH ADDITIONAL CONVECTIVE BANDS TO
THE SOUTH AND EAST OF THE LOW LEVEL CIRCULATION CENTER (LLCC). THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED 
CENTER IN THE MSI LOOP ALONG WITH THE LLCC IN THE AMSR2
MICROWAVE IMAGERY. THE INITIAL INTENSITY REMAINS  55 KNOTS BASED ON
A COMBINATION OF OBJECTIVE AND SUBJECTIVE DVORAK INTENSITY ESTIMATES
RANGING FROM T3.0 (45 KNOTS) TO T3.5 (55 KNOTS). ENVIRONMENTAL 
CONDITIONS REMAIN MARGINALLY FAVORABLE WITH GOOD EQUATORWARD AND 
POLEWARD OUTFLOW AND LOW VERTICAL WIND SHEAR (VWS), WARM SEA SURFACE 
TEMPERATURES (SSTS) OFFSET BY DRY AIR ENTRAINMENT.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 33 KTS AT 090220Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: MODERATE POLEWARD OUTFLOW

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 FORECAST TO TRACK
NORTH-NORTHWESTWARD ON THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE
(STR) POSITIONED TO THE NORTHEAST THROUGH THE REMAINDER OF THE 
FORECAST PERIOD. LANDFALL IS EXPECTED TO THE WEST OF BUSAN AFTER TAU 
24, WITH THE SYSTEM RAPIDLY MOVING INTO CHINA BY TAU 72. IN TERMS OF
INTENSITY, THE MARGINALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY
WARM SEA SURFACE TEMPERATURES (SSTS), GOOD EQUATORWARD AND POLEWARD
OUTFLOW WILL PROMOTE SLIGHT INTENSIFICATION TO A PEAK OF 60 KNOTS.
BY TAU 24, THE SYSTEM WILL MAKE LANDFALL AND THE INTERACTION WITH THE 
KOREAN PENINSULA WILL LEAD TO DETERIORATION TO 40 KNOTS BY TAU 36 AND 
THEN TO EVENTUAL DISSIPATION BY TAU 72. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN GOOD VERY
GOOD AGREEMENT WITH A 80NM CROSS-TRACK SPREAD IN SOLUTIONS BY TAU
72. THEREFORE, THE JTWC TRACK FORECAST IS PLACED WITH HIGH
CONFIDENCE. THERE IS MEDIUM CONFIDENCE IN THE JTWC INTENSITY
FORECAST WITH INTENSITY GUIDANCE SHOWING A STEADY DECREASING TREND
AFTER TAU 24 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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