WDPN32 PGTW 041500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN)       
WARNING NR 034//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.4N 125.8E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 120 NM WEST-NORTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED PROXYVIS SATELLITE IMAGERY DEPICTS A LARGE (600NM DIAMETER) 
SYSTEM WITH TIGHTLY-CURVED BANDING WRAPPING INTO A DEFINED LOW-LEVEL 
CIRCULATION CENTER (LLCC), WHICH SUPPORTS THE INITIAL POSITION WITH 
HIGH CONFIDENCE. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY REVEALS 
DEEP CONVECTIVE BANDING WRAPPING INTO A BROAD CENTER WITH FLARING, 
DISORGANIZED CONVECTION NEAR THE CENTER. ENVIRONMENTAL CONDITIONS 
REMAIN MARGINAL DUE PRIMARILY TO THE UPWELLING COOLER WATER OFFSET 
SOMEWHAT BY THE MODERATE RADIAL OUTFLOW AND LOW VERTICAL WIND SHEAR. A 
040947Z RCM-3 SAR IMAGE INDICATES A MEDIUM-SIZED (55 TO 65NM DIAMETER) 
CORE OF LIGHT WINDS WITH A BROAD SWATH OF STORM-FORCE WINDS DISPLACED 
ABOUT 50NM FROM THE CENTER. THE INITIAL POSITION IS PLACED WITH HIGH 
CONFIDENCE BASED ON A RELIABLE 041200Z JMA WEATHER RADAR FIX AND A
041200Z HM9 INFRARED IMAGE. THE INITIAL INTENSITY OF 60 KTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK
ESTIMATES RANGING FROM 55 TO 65 KNOTS AND AFOREMENTIONED SAR IMAGE.
THE 041300Z D-PRINT ESTIMATE OF 58 KNOTS AND THE 041300Z CIMSS SATCON
ESTIMATE OF 62 KNOTS ALSO SUPPORT THE INITIAL INTENSITY ESTIMATE.

INITIAL WIND RADII BASIS: SAR DATA, SURFACE OBSERVATIONS

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) POSITIONED
TO THE SOUTH AND SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 62 KTS AT 041300Z
   CIMSS ADT: 32 KTS AT 041130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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: TROPICAL STORM (TS) 06W IS ACCELERATING
EAST-NORTHEASTWARD AND IS FORECAST TO CONTINUE THROUGH TAU 48 ALONG
THE NORTHERN PERIPHERY OF THE NER. DUE TO THE UPWELLING COOL WATER,
THE SYSTEM IS EXPECTED TO WEAKEN SLIGHTLY TO 55 KNOTS BY TAU 12,
WHICH IT WILL MAINTAIN THROUGH TAU 36. AFTER TAU 48, THE GFS AND
ECMWF MODELS CONTINUE TO DEVELOP ANOTHER SYSTEM TO THE
EAST-SOUTHEAST OF TS 06W, WHICH WILL DISRUPT THE STEERING FLOW
SUPPORTING THE CLIMATOLOGICALLY SLOW TRACK SPEEDS AFTER TAU 48. AFTER 
TAU 48, ENVIRONMENTAL CONDITIONS SHOULD GRADUALLY IMPROVE ESPECIALLY 
SST VALUES, WHICH WILL INCREASE TO 28-29C, AND POLEWARD OUTFLOW. THIS 
SHOULD ALLOW A MODEST REINTENSIFICATION TO 65 KNOTS BY TAU 96. AFTER 
TAU 96, TS 06W WILL GRADUALLY WEAKEN DUE TO FRICTIONAL EFFECTS AS IT 
TRACKS OVER WESTERN JAPAN.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN FAIR AGREEMENT
WITH A 110NM CROSS-TRACK SPREAD IN SOLUTIONS AT TAU 72. AFTER TAU
72, THE GUIDANCE DIVERGES SLIGHTLY WITH A 157NM CROSS-TRACK SPREAD
AT TAU 120. THE JGSM TRACKER IS THE WESTERNMOST OUTLIER WITH A
TRACK OVER KYUSHU WHILE NAVGEM IS THE EASTERNMOST OUTLIER WITH A
TRACK OVER SHIKOKU ISLAND. THE REMAINDER OF THE GUIDANCE IS TIGHTLY
CLUSTERED WITH A TRACK BETWEEN KYUSHU AND SHIKOKU ISLANDS. THE
040000Z ECMWF (EPS) AND 040600Z GFS (GEFS) ENSEMBLES HAVE COME INTO
BETTER AGREEMENT BUT STILL INDICATE SOLUTIONS WEST OF KYUSHU TO THE
KII PENINSULA SUPPORTING THE TRACK FORECAST WITH MEDIUM CONFIDENCE.

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