WDPN31 PGTW 070300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 025//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.2N 139.9E
   INITIAL INTENSITY: 125 KTS
   GEOGRAPHIC REFERENCE: 915 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 56 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS THE
INCREASINGLY CLOUD-FILLED INNER EYE OF TYPHOON (TY) 09W (BAVI)
MAKING A WANDERING WEST-NORTHWESTWARD TRACK UNDER THE EFFECTS OF
TROCHOIDAL MOTION AS THE SYSTEM CONTINUES TO UNDERGO AN EYEWALL
REPLACEMENT CYCLE (ERC). THE ERC IS FURTHER EVIDENCED BY A 072202Z
SSMIS 89 GHZ MICROWAVE IMAGE IN WHICH THE STILL-DEVELOPING OUTER
EYEWALL HAS BECOME THE DOMINANT MICROWAVE EYE FEATURE, WITH LITTLE
REMAINING STRUCTURE OF THE PREVIOUS INNER EYEWALL. ANIMATED WATER
VAPOR IMAGERY HIGHLIGHTS CONTINUED RADIAL OUTFLOW ALONG WITH A
RESPECTABLE EQUATORWARD AND WESTWARD CHANNEL. A 062027Z RCM-2 SAR
IMAGE CONFIRMED THE VERY BROAD WIND FIELD ASSOCIATED WITH THE
SYSTEM, WHICH IS FURTHER CORROBORATED BY A 070003Z METOP-B ASCAT
PARTIAL PASS THAT REVEALED THE 550 NM DIAMETER EXTENT OF STORM
FORCE WINDS IN THE EASTERN SEMICIRCLE. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON REMNANT INNER EYE FEATURE IN
THE MSI. THE INITIAL INTENSITY OF 125 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON 120 KTS WIND VELOCITIES IN THE PREVIOUSLY
MENTIONED SAR PASS, BALANCED BY THE SPREAD OF AGENCY DVORAK FIXES
AND CIMSS INTENSITY ESTIMATES. THE ENVIRONMENT IS CHARACTERIZED AS
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: SAR DATA AND OBJECTIVE BEST TRACK

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T6.5 - 127 KTS
   RCTP: T7.5 - 155 KTS
   KNES: T6.5 - 127 KTS
   CIMSS SATCON: 134 KTS AT 062330Z
   CIMSS ADT: 129 KTS AT 070000Z
   CIMSS AIDT: 123 KTS AT 070000Z
   CIMSS D-MINT: 127 KTS AT 062202Z
   CIMSS D-PRINT: 133 KTS AT 070030Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: MODERATE RADIAL OUTFLOW IMMEDIATELY SURROUNDING
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: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TYPHOON 09W (BAVI) HAS CONTINUED ITS
WEST-NORTHWESTWARD TRACK AT A SLOWER RATE OVER THE PAST 6 HOURS AS
THE ERC CONTINUES. THE TRACK IS FORECAST TO REMAIN ON A
WEST-NORTHWESTWARD TRAJECTORY OVER THE NEXT 30 HOURS AS THE
STEERING RIDGE OVER OKINAWA 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 TY 09W JUST
NORTHEAST OF TAIWAN AROUND TAU 96 BEFORE MAKING LANDFALL IN EASTERN
CHINA. ANALYSIS OF THE ONGOING ERC INDICATES THAT THE CYCLE WILL
COMPLETE IN THE NEAR TERM AND ALLOW THE CENTRAL CORE OF THE SYSTEM
TO RECONSOLIDATE AND ENABLE A BRIEF PERIOD OF INTENSIFICATION
THROUGH TAU 24 IN A FAVORABLE ENVIRONMENT. PERSISTENT 15-20 KTS OF
NORTHEASTERLY VWS ARE EXPECTED TO BE THE PRIMARY FACTOR
CONTRIBUTING TO A GRADUAL WEAKENING TREND AFTER TAU 24, UNTIL
EVENTUAL LANDFALL IN EASTERN CHINA WILL RESULT IN RAPID DISSIPATION
OVER LAND.

MODEL DISCUSSION: MODEL TRACK GUIDANCE REMAINS IN GOOD AGREEMENT
ABOUT THE NORTHWESTWARD TURN, WITH MINIMAL TRACK SPREAD THROUGH TAU
72. NAVGEM AND THE ECMWF DETERMINISTIC MODELS MAKE UP THE
WESTERNMOST SOLUTIONS, WHICH SUGGEST A TRACK OVER NORTHEASTERN
TAIWAN. EXCLUDING THE WESTERN OUTLIERS, THE CROSS-TRACK SPREAD
INCREASES TO 140 NM AT TAU 120, AFTER LANDFALL. THE ALONG-TRACK
REMAINS SMALL THROUGH TAU 96, THEN INCREASES TO 240 NM AT TAU 120
WITH NAVGEM BEING A SIGNIFICANTLY SLOWER OUTLIER. THE JTWC TRACK
FORECAST IS PLACED WITH HIGH CONFIDENCE CLOSE TO THE MULTI-MODEL
CONSENSUS, HEDGED SLIGHTLY TO THE EASTERN SIDE OF GUIDANCE TO
ACCOUNT FOR THE NAVGEM AND ECMWF CONTRIBUTIONS. MODEL INTENSITY
GUIDANCE FROM COAMPS-TC, HAFS-A, AND HWRF ARE IN GOOD AGREEMENT
ABOUT THE BRIEF PERIOD OF INTENSIFICATION OVER THE NEXT 24 HOURS
AND ALL MODELS AGREE ON THE EVENTUAL GRADUAL WEAKENING OF 09W
THROUGH THE REMAINDER OF THE FORECAST. DECAY SHIPS SOLUTIONS REMAIN
OUTLIERS ON THE LOW END OF GUIDANCE AND THE JTWC INTENSITY FORECAST
IS PLACED WITH MEDIUM CONFIDENCE 5-10 KTS ABOVE THE MULTI-MODEL
CONSENSUS TO ACCOUNT FOR THEIR CONTRIBUTION AND THE EXPECTATION OF
INTENSIFICATION IN THE NEAR TERM.  

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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