WDPN31 PGTW 302100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 12W (DOLPHIN) WARNING NR 
016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.9N 162.9E
   INITIAL INTENSITY: 135 KTS
   GEOGRAPHIC REFERENCE: 2010 NM EAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 44 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS SUPER
TYPHOON 12W (DOLPHIN) WITH A CLOUD-FILLED 20 NM EYE THAT HAS
STARTED TO CLEAR OUT AS THE SYSTEM RECOVERS FROM AN EYEWALL
REPLACEMENT CYCLE (ERC). IN ADDITION TO THE CLEARING EYE, THE CLOUD
TOPS SURROUNDING THE EYEWALL HAVE COOLED AND BECOME MORE
SYMMETRICAL OVER THE PAST 6 HOURS. THE LACK OF RECENT
HIGH-RESOLUTION MICROWAVE IMAGERY HAS CAUSED THERE TO BE AMBIGUITY
IN THE CURRENT STRUCTURE OF THE CORE OF THE SYSTEM AND STATUS OF
THE ERC. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON THE EYE IN ANIMATED EIR IMAGERY. THE INITIAL INTENSITY OF 135
KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK
AND CIMSS INTENSITY ESTIMATES LISTED BELOW. THE CURRENT ADT AND
AIDT ESTIMATES FROM CIMSS ARE ANALYZED TO BE UNDERESTIMATING THE
INTENSITY OF THE SYSTEM DUE TO THE BRIEF FILLING OF THE EYE.
ENVIRONMENTAL ANALYSIS INDICATES THAT 12W IS IN A HIGHLY FAVORABLE
ENVIRONMENT CHARACTERIZED BY STRONG RADIAL OUTFLOW ALOFT, LOW (5-10
KTS) VERTICAL WIND SHEAR, AND VERY WARM (30-31 C) SEA SURFACE
TEMPERATURES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SOUTHWESTERN EXTENT OF AN EXPANSIVE
SUBTROPICAL RIDGE (STR) COMPLEX

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T7.0 - 140 KTS 
   RCTP: T7.5 - 155 KTS
   KNES: T6.5 - 127 KTS
   PHFO: T6.5 - 127 KTS
   CIMSS SATCON: 135 KTS AT 301530Z
   CIMSS D-MINT: 131 KTS AT 301501Z
   CIMSS D-PRINT: 135 KTS AT 301800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG RADIAL

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: STY 12W IS FORECAST TO CONTINUE TRACKING
WEST-NORTHWESTWARD, ALONG THE SOUTHWESTERN EXTENT OF AN EXPANSIVE
RIDGING COMPLEX SITUATED TO THE NORTHEAST THROUGH TAU 60. NEAR TAU
60, THE UPPER-LEVEL TROUGH THAT IS CURRENTLY OVER HONSHU WILL BE
POSITIONED TO THE NORTH OF 12W AND WILL BEGIN TO FILL. AFTER THE
TROUGH FILLS AND PROPAGATES FURTHER EASTWARD, RIDGING WILL BUILD IN
FROM BOTH THE NORTHEAST AND NORTHWEST OF 12W, CAUSING THE TRACK TO
TURN MORE WESTWARD. THE RIDGE THAT WILL BE POSITIONED OVER THE
KOREAN PENINSULA WILL EVENTUALLY BECOME THE PRIMARY STEERING
MECHANISM AROUND TAU 96 AS THE SYSTEM HEADS TOWARD THE RYUKYU
ISLANDS. IN TERMS OF INTENSITY, 12W IS FORECAST TO GENERALLY
MAINTAIN ITS CURRENT INTENSITY THROUGH TAU 36 WITH SOME POSSIBLE
FURTHER FLUCTUATIONS IN INTENSITY DEPENDING ON FURTHER ERC EVENTS
AND INNER-CORE DYNAMICS. BY TAU 48, GRADUALLY LOWERING OCEAN HEAT
CONTENT, INCREASING NORTHEASTERLY VERTICAL WIND SHEAR, AND
WEAKENING POLEWARD OUTFLOW WILL SERVE TO STEADILY WEAKEN THE SYSTEM
AS IT MOVES OFF TO THE WEST. IN ADDITION TO THOSE MENTIONED
ENVIRONMENTAL CHARACTERISTICS, THE WIND FIELD OF 12W IS EXPECTED TO
DRAMATICALLY EXPAND AROUND TAU 96, WHICH WILL FURTHER SUPPORT A
STEADY DECLINE ON THE INTENSITY OF THE SYSTEM.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE CONTINUES TO BE IN
VERY GOOD AGREEMENT WITH NO SIGNIFICANT OUTLIERS PRESENT.
CROSS-TRACK SPREAD AT TAU 72 IS MEASURED TO BE ABOUT 95 NM WHICH
REMAINS AROUND THE SAME THROUGH TAU 120. AS A RESULT, THE JTWC
TRACK FORECAST IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS
THROUGHOUT THE FORECAST PERIOD WITH HIGH CONFIDENCE. INTENSITY
GUIDANCE GENERALLY AGREES ON A STEADY INTENSITY THROUGH TAU 36-48
FOLLOWED BY STEADY WEAKENING THROUGH TAU 120. OF NOTE, HAFS-A IS
THE QUICKEST TO WEAKEN 12W WITH AN INTENSITY OF AROUND 75 KTS AT
TAU 120. THE JTWC INTENSITY FORECAST CLOSELY FOLLOWS THE CONSENSUS
THROUGH TAU 72 AND THEN IS PLACED ON THE HIGHER END OF THE GUIDANCE
ENVELOPE THROUGH TAU 120 WITH MEDIUM CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: HIGH
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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