WDPN31 PGTW 102100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 040//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.8N 125.2E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 215 NM SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 46 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS STEADILY
CONSOLIDATING CONVECTION AROUND THE INNER CORE THAT APPEARS TO BE
REINVIGORATING THE REMNANTS OF A PREVIOUS INNER EYEWALL. THE
CLOUD-FILLED EYE HAS BECOME COMPLETELY OBSCURED BY THE DEVELOPING
CENTRAL DENSE OVERCAST AROUND THE INNER CORE OVER THE PAST FEW
HOURS. MEANWHILE, A LARGER RADIUS CONVECTIVE BAND THAT WAS
PREVIOUSLY ASSOCIATED WITH THE RADIUS OF MAXIMUM WINDS HAS
EXHIBITED MORE DISCONTINUOUS DEEP CONVECTION WHERE IT IS SPIRALING
INTO THE DEVELOPING CORE. ANIMATED RADAR IMAGERY CONFIRMS THIS
CONFIGURATION, SHOWING A LARGE RAINBAND SPIRALING CONCENTRICALLY
INTO THE MORE CONTINUOUS INNER BAND. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON THE CENTER OF ROTATION IN ANIMATED
EIR AND RADAR IMAGERY. THE INITIAL INTENSITY IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON A BLEND OF RELATIVELY LOW CIMSS
OBJECTIVE INTENSITY ESTIMATES AND HIGHER T4.5-5.5 AGENCY DVORAK
FIXES. CONSIDERING THE IMPROVEMENT IN THE CENTRAL STRUCTURE, THE
INITIAL INTENSITY IS ASSESSED ON THE LOW END OF THE AGENCY FIXES.
THE ENVIRONMENT REMAINS FAVORABLE, WITH HIGH SEA SURFACE
TEMPERATURES, LOW VERTICAL WIND SHEAR (VWS), AND MODERATE RADIAL
OUTFLOW ALOFT. UPWELLING OF COOLER WATER IN AN AREA OF MODERATE
OCEAN HEAT CONTENT VALUES NEAR THE CORE MAY BE AN INHIBITING
FACTOR.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED SOUTH OF HONSHU

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T5.5 - 102 KTS
   CIMSS ADT: 51 KTS AT 101800Z
   CIMSS AIDT: 51 KTS AT 101800Z
   CIMSS D-MINT: 72 KTS AT 101414Z
   CIMSS D-PRINT: 80 KTS AT 101800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE 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: TYPHOON (TY) 09W (BAVI) HAS CONTINUED
NORTHWESTWARD AT A SLIGHTLY FASTER 14 KT SPEED OVER THE PAST 6
HOURS UNDER THE STEERING INFLUENCE OF THE STR TO THE NORTHEAST. THE
TRACK IS FORECAST TO CONTINUE A NORTHWESTWARD TRAJECTORY OVER THE
NEXT 36 HOURS AS IT APPROACHES THE AXIS OF THE STEERING RIDGE, THEN
TURN POLEWARD THROUGH THE REMAINDER OF THE FORECAST PERIOD. THE
CENTER OF TY 09W IS EXPECTED TO PASS THROUGH THE RYUKYU ISLANDS IN
THE NEXT 4-6 HOURS, THEN MAKE A CPA TO TAIPEI OF 109 NM AT 110700Z
ON ITS WAY TO LANDFALL IN EASTERN CHINA JUST BEFORE TAU 24. GIVEN
THE FAVORABLE ENVIRONMENTAL CONDITIONS THAT ARE EXPECTED TO PERSIST
UNTIL TY BAVI MAKES LANDFALL, THE INTENSITY IS FORECAST TO REMAIN
STEADY THROUGH THE NEXT 12 HOURS, THEN GRADUALLY DECREASE UP UNTIL
LANDFALL, LIMITED BY THE ONGOING REORGANIZATION OF THE CENTRAL
CORE. AFTER LANDFALL, THE INTENSITY IS EXPECTED TO RAPIDLY DECAY
OVER LAND, WITH DISSIPATION ANTICIPATED BY TAU 60.

MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN VERY TIGHT AGREEMENT,
WITH A 70 NM CROSS-TRACK SPREAD AT TAU 36, WELL AFTER LANDFALL. THE
TRACK AROUND THE STR AXIS OVER LAND INTRODUCES A FAIR BIT OF
UNCERTAINTY AFTER TAU 36, HOWEVER, THE GENERAL TREND IS EVIDENT IN
THE ENTIRE MODEL SUITE. THEREFORE, THE JTWC FORECAST TRACK IS
PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.
THERE ARE NO SIGNIFICANT OUTLIERS AMONG THE MODEL INTENSITY
GUIDANCE, WITH ALL SOLUTIONS SUGGESTING A SIMILAR TREND OF NEAR
SUSTAINMENT IN THE SHORT TERM, FOLLOWED BY GRADUAL WEAKENING AS THE
SYSTEM APPROACHES LANDFALL. AFTER LANDFALL, ALL MODELS SHOW RAPID
DECAY. THE JTWC INTENSITY FORECAST IS PLACED WITH MEDIUM CONFIDENCE
SLIGHTLY ABOVE THE MULTI-MODEL CONSENSUS THROUGH TAU 24, THEN BELOW
THE CONSENSUS THROUGH THE REMAINDER OF THE FORECAST TO ACCOUNT FOR
RAPID DECAY OVER LAND.

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