WDPN31 PGTW 062100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 09W (BAVI) WARNING NR 
024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.9N 141.1E
   INITIAL INTENSITY: 135 KTS
   GEOGRAPHIC REFERENCE: 977 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 60 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
WELL-DEFINED 20 NM EYE FEATURE SURROUNDED BY AN INCREASINGLY RAGGED
CENTRAL DENSE OVERCAST. DVORAK-ENHANCED INFRARED IMAGERY SHOWS
CONVECTIVE CLOUD TOPS GRADUALLY WARMING OVER THE PAST 6 HOURS,
ESPECIALLY IN THE WESTERN SEMICIRCLE. ANIMATED WATER VAPOR IMAGERY
SUGGESTS SOME WEAK DRY AIR ENTRAINING IN THE SOUTHERN SEMICIRCLE
AND BEGINNING TO WRAP AROUND THE EASTERN SIDE OF THE SYSTEM, WHILE
EQUATORWARD AND WESTWARD OUTFLOW REMAINS GOOD. A 061633Z AMSR-2 89
GHZ MICROWAVE IMAGED REVEALED THE STRUCTURAL EFFECT OF THE NASCENT
DRY AIR ENTRAINMENT, WITH A NOTABLE SHALLOWING OF CONVECTIVE
BANDING IN THE SOUTHEASTERN QUADRANT. THE MICROWAVE IMAGERY ALSO
DEPICTS AN ONGOING EYEWALL REPLACEMENT CYCLE (ERC), WITH A RAGGED
INNER MICROWAVE EYE NOT-YET FULLY ENCIRCLED BY A PERSISTENT OUTER
EYEWALL. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE
BASED ON THE CENTER OF THE WELL-DEFINED EYE IN EIR. THE INITIAL
INTENSITY OF 135 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED
PRIMARILY ON T7.0 AGENCY DVORAK FIXES, HEDGED ON THE LOWER SIDE AS
A RESULT OF THE DEGRADING SATELLITE PRESENTATION. THE ENVIRONMENT
REMAINS FAVORABLE FOR INTENSITY SUSTAINMENT, WITH VERY WARM (29-30
C) SEA SURFACE TEMPERATURES AND HIGH OCEAN HEAT CONTENT BEING
MODERATED BY PERSISTENT 15-20 KTS OF EASTERLY VERTICAL WIND SHEAR
(VWS).

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SOUTHEASTERN FLANK OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED NEAR OKINAWA

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   RJTD: T7.0 - 140 KTS 
   RCTP: T7.5 - 155 KTS
   KNES: T7.0 - 140 KTS 
   CIMSS SATCON: 139 KTS AT 061700Z
   CIMSS ADT: 132 KTS AT 061800Z
   CIMSS AIDT: 128 KTS AT 061800Z
   CIMSS D-MINT: 139 KTS AT 061552Z
   CIMSS D-PRINT: 139 KTS AT 061800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: MODERATE RADIAL OUTFLOW IMMEDIATELY SURROUNDIN
THE STORM CENTER WITH ENHANCED OUTFLOW IN THE EQUATORWARD AND
WESTWARD DIRECTIONS IN THE OUTER PERIPHERY.

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: SUPER TYPHOON (STY) 09W (BAVI) HAS TAKEN A
SLIGHTLY MORE WESTWARD TRACK OVER THE PAST 6 HOURS UNDER THE
STEERING INFLUENCE OF THE STR SITUATED TO THE NORTHWEST. THE TRACK
IS FORECAST TO REMAIN ON A WEST-NORTHWESTWARD TRAJECTORY OVER THE
NEXT 36 HOURS AS THE STEERING RIDGE MIGRATES NORTHWARD OVER KYUSHU
AND BEGINS TO WEAKEN. AFTER TAU 36, A DEEP-LAYER SUBTROPICAL RIDGE
BUILDS IN FROM THE NORTHEAST AND TAKES OVER AS THE PRIMARY STEERING
MECHANISM, RESULTING IN A NORTHWESTWARD TRACK FOR THE REMAINDER OF
THE FORECAST PERIOD. THIS TRACK BRINGS THE CENTER OF STY 09W JUST
NORTHEAST OF TAIWAN AFTER TAU 96 BEFORE MAKING LANDFALL IN EASTERN
CHINA. STY BAVI IS EXPECTED TO MAINTAIN ITS CURRENT INTENSITY OF
135 KTS THROUGH TAU 24 IN AN ENVIRONMENT OF WARM SEA SURFACE
TEMPERATURES AND AS THE SYSTEM IS UNDERGOING ERC. AFTER TAU 24,
PERSISTENT 15-20 KTS OF VWS IS EXPECTED TO OVERCOME THE MORE
FAVORABLE ENVIRONMENTAL FACTORS AND INITIATE A GRADUAL WEAKENING
TREND THROUGH TAU 96. AFTER TAU 96, LAND INTERACTION OVER TAIWAN
AND THE SUBSEQUENT LANDFALL IN EASTERN CHINA WILL CAUSE RAPID
DISSIPATION OF 09W.

MODEL DISCUSSION: MODEL TRACK GUIDANCE HAS BECOME BETTER ALIGNED
WITH THE LATEST MODEL RUN, WITH MINIMAL TRACK SPREAD THROUGH TAU 72
AND A 145 NM CROSS-TRACK SPREAD AS THE SYSTEM MAKES LANDFALL IN
EASTERN CHINA. EXCEPTING NAVGEM AS A SLOW OUTLIER, THE ALONG-TRACK
SPREAD OF CONSENSUS MODELS REMAINS MINIMAL THROUGH TAU 120. THE
MODEL PACKAGE AS A WHOLE HAS SHIFTED FARTHER TO THE SOUTHWEST AND
THE PREVIOUS DISPARITY OF PHYSICS-BASED MODELS AND EXPERIMENTAL AI
SOLUTIONS ABOUT THE TRACK IN THE VICINITY OF TAIWAN HAVE BECOME
NEGLIGIBLE. THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE
MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE THROUGHOUT THE FORECAST
PERIOD. MODEL INTENSITY GUIDANCE LARGELY FALLS WITHIN A 20KT
ENVELOPE, WITH THE NOTABLE EXCEPTION OF HWRF, WHICH SUGGESTS A
PERIOD OF INTENSIFICATION UP TO 170 KTS BY TAU 60. THE DECAY SHIPS
SOLUTIONS MAKE UP THE LOW END OF GUIDANCE, SUGGESTING A MORE RAPID
WEAKENING THROUGH THE ENTIRE PERIOD. THE JTWC INTENSITY FORECAST IS
PLACED SLIGHTLY ABOVE THE MULTI-MODEL CONSENSUS WITH MEDIUM
CONFIDENCE TO ACCOUNT FOR THE SHIPS SOLUTIONS AND IN CONSIDERATION
OF THE STILL-FAVORABLE ENVIRONMENTAL CONDITIONS.   

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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