WDPN32 PGTW 011500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 06W (KHANUN) WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.3N 127.9E
   INITIAL INTENSITY: 115 KTS
   GEOGRAPHIC REFERENCE: 72 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 47 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
RESPLENDENT TYPHOON STRENGTH CIRCULATION, WITH A 20NM CRYSTAL CLEAR
EYE AND TIGHTLY WRAPPING BANDS OF DEEP CONVECTION. A 011052Z GMI
89GHZ COLOR COMPOSITE MICROWAVE IMAGE INDICATES AN ASYMMETRIC
CONVECTIVE BANDING FIELD, DUE TO THE ADVECTION OF COOL DRY AIR FROM
THE NORTH INTO THE WESTERN PORTION OF 06W. DESPITE THIS DRY AIR
INTRUSION, THE CORE OF THE CIRCULATION REMAINS ROBUST, WITH A THICK
AND INTACT EYE WALL EVIDENT IN THE GMI IMAGERY. THE INITIAL POSITION 
IS PLACED WITH HIGH CONFIDENCE BASED ON A CLEAR EYE FEATURE IN EIR 
AND 
GMI IMAGERY. THE INITIAL INTENSITY OF 115 KTS IS ASSESSED WITH MEDIUM 
CONFIDENCE BASED ON A NEAR TOTAL AGREEMENT AMONGST AVAILABLE 
INTENSITY 
GUIDANCE WITH THE EXCEPTION OF A RECENT 010922Z RCM-3 SYNTHETIC 
APERTURE RADAR (SAR) PASS. AGENCY DVORAK INTENSITY ESTIMATES, CIMSS 
ADT, AIDT, D-MINT AND D-PRINT ALL SUPPORT 115 KTS WITH MINIMAL 
VARIABILITY, WHILE THE AFOREMENTIONED SAR PASS INDICATES A VMAX OF 
87KTS. AT FACE VALUE THIS SAR PASS MAY SEEM PREPOSTEROUS, BUT THIS 
SCALAR WIND PRODUCT IS AMONGST THE HIGHEST QUALITY SATELLITE DATA 
AVAILABLE AND TYPICALLY OUTWEIGHS MODEL DERIVED DATA IN TERMS OF 
RELIABILITY AND ACCURACY. DUE TO THIS DISSONANCE IN AVAILABLE DATA, 
THE OVERALL CONFIDENCE IN INITIAL INTENSITY IS SET AT MEDIUM.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYER STR
CENTERED OVER THE YELLOW SEA.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T6.0 - 115 KTS
   RCTP: T6.0 - 115 KTS
   KNES: T6.0 - 115 KTS
   CIMSS ADT: 109 KTS AT 011200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: UPPER-LEVEL DRY AIR INTRUSION

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: TYPHOON 06W (KHANUN) IS FORECAST TO CONTINUE
TRACKING WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR
TO THE NORTH. THE SYSTEM IS FORECAST TO GRADUALLY WEAKEN OVER THE
NEXT 24 HOURS DUE TO PERSISTENT AND BUILDING VERTICAL WIND SHEAR
AND UPPER LEVEL DRY AIR ENTRAINMENT. BY TAU 36, THE UPPER LEVEL
STEERING PATTERN WILL BEGIN TO SHIFT. THE STR TO THE NORTH WILL
GRADUALLY SHIFT WESTWARD AND THE NEAR EQUATORIAL RIDGE (NER) TO THE
SOUTH WILL CONTINUE TO BUILD. BY TAU 48, THIS WILL SET UP A
COMPETING STEERING ENVIRONMENT THAT WILL LIKELY RESULT IN
QUASI-STATIONARY (QS) OR ERRATIC TRACK MOTION. DURING THIS TIME,
SLOW TRACK SPEEDS COMBINED WITH A TYPHOON STRENGTH LOW PRESSURE
CENTER WILL UPWELL COPIOUS AMOUNTS OF COOLER WATER BENEATH 06W. BY
TAU 72, THIS COOLER WATER COMBINED WITH ONGOING DRY AIR ENTRAINMENT
WILL EXACERBATE THE WEAKEN TREND OF THE SYSTEM. BY TAU 96, NOW
BELOW TYPHOON STRENGTH, THE RIDGES TO THE NORTH AND SOUTH OF THE
SYSTEM BOTH REORIENT TO THE WEST AND FORCE 06W NORTHEASTWARD. THE
LATEST MODEL RUN FORESHADOWS POTENTIALLY EVEN MORE IMPACTS FOR
KADENA BEYOND TAU 96, PRIMARILY THAT THE STR TO THE NORTH MAY SPLIT
AND BUILD A NEW RIDGE NORTHEAST OF 06W. IF THIS NEW RIDGE MANIFESTS, 
IT COULD ONCE AGAIN STALL THE SYSTEMS MOVEMENT, RESULTING IN FURTHER 
QS OR ERRATIC TRACK MOTION IVO KADENA.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT THROUGH
TAU 48, WITH ALL MEMBERS GENERALLY FOLLOWING THE JTWC TRACK
FORECAST. AFTER TAU 48 HOWEVER, MODEL SPREAD DRAMATICALLY
INCREASES, EGRI AND UKMET DRIVE THE SYSTEM TOWARD MAINLAND CHINA
WHILE THE REMAINING MEMBERS TAKE A SHARP TURN AND FAN OUT GENERALLY
NORTHEASTWARD THROUGH THE FORECAST PERIOD. FOR THIS REASON THE JTWC
TRACK FORECAST IS PLACED INITIALLY WITH MEDIUM CONFIDENCE AND WITH
LOW CONFIDENCE THEREAFTER. RELIABLE MODEL INTENSITY GUIDANCE IS IN
GOOD AGREEMENT, WITH ALL MEMBERS SLOWLY WEAKENING THE SYSTEM THROUGH 
TAU 36. THE SPREAD IN MEMBER GUIDANCE INCREASES AFTER TAU 48 AS 
VARIOUS MEMBERS ATTEMPT TO RESOLVE THE COMPLEX ENVIRONMENT AND 
IMPACTS 
OF THE AFOREMENTIONED UPWELLING. WITH THAT BEING SAID, THE JTWC 
INTENSITY FORECAST REMAINS ON THE UPPER END OF THE GUIDANCE ENVELOPE 
THROUGHOUT THE FORECAST PERIOD. FOR THESE REASON THE JTWC INTENSITY 
FORECAST IS PLACED INITIALLY WITH MEDIUM CONFIDENCE AND WITH LOW 
CONFIDENCE THEREAFTER.

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