WDPN32 PGTW 080900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN) WARNING NR 
049//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 29.4N 130.7E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 228 NM SOUTH-SOUTHEAST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND ANIMATED RADAR
IMAGERY DEPICTS DEEP CONVECTIVE BANDING WRAPPING INTO A BROAD
EXPOSED CENTER. A 080418Z AMSR2 37GHZ MICROWAVE IMAGE SHOWS
TIGHTLY-CURVED DEEP CONVECTIVE BANDING WRAPPING TIGHTLY INTO A
DEFINED LOW-LEVEL CIRCULATION CENTER AND ALSO SUPPORTS THE INITIAL
POSITION. INITIAL INTENSITY IS ALSO PLACED WITH MEDIUM CONFIDENCE
BASED ON A COMBINATION OF AGENCY AND AUTOMATED DVORAK
ESTIMATES. ENVIRONMENTAL ANALYSIS INDICATES A MARGINAL ENVIRONMENT
WITH STRONG EQUATORWARD OUTFLOW, LOW VERTICAL WIND SHEAR AND WARM
SST (29C) OFFSET BY DRY AIR ENTRAINMENT.

INITIAL WIND RADII BASIS: PERSISTENCE 

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


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 42 KTS AT 080143Z
   CIMSS ADT: 32 KTS AT 080530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG 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 FORECAST TO TRACK
NORTH-NORTHWESTWARD OVER THE NEXT 36 HOURS AS A SUBTROPICAL RIDGE
(STR) POSITIONED TO THE EAST AND NORTHEAST WILL TAKE OVER AS THE
PRIMARY STEERING MECHANISM, THROUGH THE REMAINDER OF THE FORECAST
PERIOD. LANDFALL IS EXPECTED TO THE WEST OF BUSAN AFTER TAU 36,
WITH THE SYSTEM RAPIDLY MOVING INTO NORTHEASTERN CHINA BY TAU 96.
IN REGARD TO INTENSITY, THE SYSTEM IT WILL MOVE OVER WARM SEA
SURFACE TEMPERATURES (SSTS), AT THE SAME TIME, OUTFLOW WILL
STEADILY IMPROVE, WITH INCREASED POLEWARD OUTFLOW, WHICH WILL
ENABLE INCREASED CONVECTION. THESE COMBINE FACTORS SHOULD ALLOW THE
SYSTEM TO INTENSITY TO A PEAK OF 55 KNOTS BY TAU 36. AFTERWARD
INTERACTION WITH THE KOREAN PENINSULA WILL LEAD TO GRADUAL
DETERIORATION TO 45 KNOTS AND THEN TO EVENTUAL DISSIPATION BY TAU
96. 


MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT WITH A 130NM CROSS-TRACK SPREAD IN SOLUTIONS AT TAU 72 
DIVERGING TO 200NM AT TAU 96. OVERALL, THERE IS MEDIUM CONFIDENCE IN 
THE JTWC INTENSITY FORECAST WITH INTENSITY GUIDANCE INDICATING A BRIEF 
REINTENSIFICATION THROUGH TAU 36, AFTERWARD INTENSITY GUIDANCE
SHOWS A STEADY DECREASING TREND. 


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