WDPN31 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 034//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.7N 129.0E
   INITIAL INTENSITY: 110 KTS
   GEOGRAPHIC REFERENCE: 473 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 50 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON (TY)
09W (BAVI) TRANSITING NORTHWESTWARD UNDER THE INFLUENCE OF A
SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST. THE EYE FEATURE
HAS FULLY FILLED OVER THE LAST 6 HOURS, WHILE THE EYEWALL
REPLACEMENT CYCLE (ERC) IS ONGOING AND VERIFIED BY A 090452Z GW1
AMSR2 89 GHZ MICROWAVE PASS. THE INNER EYEWALL IS NEARLY FULLY
ERODED, WHILE THE OUTER WRAPPING IS STILL DEVELOPING. THE RADIUS OF
MAXIMUM WINDS (RMW) IS NOW ANALYZED AT 55 NM AND CONFIRMED BY AN
EARLIER (082114Z) RCM-1 SAR PASS. ENVIRONMENTAL ANALYSIS REVEALS
MOSTLY FAVORABLE CONDITIONS, WITH VIGOROUS UPPER-LEVEL EQUATORWARD
AND WESTWARD OUTFLOW, ROBUST OCEANIC HEAT CONTENT WITH SEA SURFACE
TEMPERATURES (SST) AT 29-30 C, OFFSET ONLY BY A MODERATE TO HIGH
(20-25 KTS) NORTHEASTERLY VERTICAL WIND SHEAR (VWS). THE INITIAL
POSITION IS LAID WITH MEDIUM CONFIDENCE BASED ON THE VISIBLE
IMAGERY AND TRACKING OF THE NOW FILLED EYE CENTER. CONCURRENTLY,
THE INITIAL INTENSITY IS ASSESSED AT 110 KTS WITH MEDIUM
CONFIDENCE. THIS VALUE RELIES ON A CONSENSUS OF AGENCY SUBJECTIVE
DVORAK FIXES LISTED BELOW, NOTING THAT OBJECTIVE CIMSS AUTOMATED
ALGORITHMS DEPICT SLIGHTLY LOWER VALUES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK

CURRENT STEERING MECHANISM: ELONGATED SUBTROPICAL RIDGING CENTERED
TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T5.5 - 102 KTS
   RJTD: T6.0 - 115 KTS
   RCTP: T5.5 - 102 KTS
   KNES: T5.5 - 102 KTS
   CIMSS SATCON: 118 KTS AT 090600Z
   CIMSS ADT: 99 KTS AT 090600Z
   CIMSS AIDT: 96 KTS AT 090600Z
   CIMSS D-MINT: 100 KTS AT 090600Z
   CIMSS D-PRINT: 98 KTS AT 090600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TY 09W IS FORECAST TO CONTINUE TRACKING
NORTHWESTWARD UNTIL LANDFALL DRIVEN BY AN ELONGATED, BUT BUILDING
AND CONSOLIDATING RIDGING CENTERED TO THE NORTHEAST. THE SYSTEM IS
EXPECTED TO PASS NEAR ISHIGAKIJIMA SHORTLY AFTER TAU 36. BETWEEN
TAU 36 AND TAU 48, THE CYCLONE IS FORECAST TO TRANSIT THE MARITIME
REGION BEFORE EXECUTING LANDFALL ONSHORE EASTERN CHINA POST TAU 48.
ONCE SITUATED INLAND OVER THE ASIAN CONTINENT, THE CYCLONIC CORE IS
EXPECTED TO DEFLECT NORTHWARD AND SUBSEQUENTLY NORTHEASTWARD AS THE
CIRCULATION INFLUENCE INTEGRATES WITH THE MID-LATITUDE
SOUTHWESTERLY FLOW. INTENSITY IS EXPECTED TO FLUCTUATE OVER THE
NEXT 48 HOURS, ESPECIALLY IN THE SHORT TERM, PRIMARILY AS A RESULT
OF THE UNCERTAINTY ASSOCIATED WITH THE ONGOING ERC. SIMULTANEOUSLY,
THE VWS IS EXPECTED TO ABATE EVER SO SLIGHTLY AROUND TAU 12. THE
MOST LIKELY SCENARIO IS SLIGHT WEAKENING DURING THE REMAINING TIME
OF THE ERC, FOLLOWED BY MINOR INTENSIFICATION OR STABILIZATION OF
THE MAXIMUM WIND SPEEDS OVER THE FOLLOWING 12 HOURS. AFTER TAU 24,
THE VWS IS EXPECTED TO START PICKING UP AGAIN, WHILE THE SYSTEM
MOVES AWAY FROM A FAVORABLE EQUATORWARD OUTFLOW CHANNEL. AT THE
SAME TIME, FAVORABLE HIGH OCEAN HEAT CONTENT IS EXPECTED TO FALL
SHARPLY ALONG THE PATH OF TY BAVI, RESULTING IN THE BEGINNING OF A
TERMINAL WEAKENING PHASE AROUND 36. AN EXPANSIVE GALE-FORCE WIND
RADII FIELD IS FORECAST TO ENCOMPASS AN AREA STRETCHING FROM TAIWAN
TO OKINAWA. EVENTUAL LANDFALL OVER THE CHINESE LANDMASS POST TAU 48
WILL INITIATE A SHARPER WEAKENING TREND AND ULTIMATELY COMPLETE
DISSIPATION.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT OVERALL, PARTICULARLY UNTIL LANDFALL WITH A CROSS-TRACK
SPREAD OF JUST 65 NM EXCLUDING THE MAIN OUTLIER - NAVGEM. MAJORITY
OF THE PHYSICS BASED MODELS TURN NORTHWARD AND NORTHEASTWARD
FOLLOWING LANDFALL, WHILE NAVGEM PREDICTS A WESTWARD TRACK.
OFFICIAL JTWC TRACK FORECAST IS LAID SLIGHTLY TO THE EAST OF THE
MULTI-MODEL CONSENSUS, OFFSETTING FOR THE PRIMARY OUTLIER. OF NOTE,
THE EXPERIMENTAL AI-BASED MODELS CONSENSUS PREDICTS AN EVEN SHARPER
RECURVATURE, WITH TRACK OVER ISHIGAKIJIMA, FOLLOWED BY A LANDFALL
85 NM NORTHEASTWARD FROM THE PHYSICS-BASED CONSENSUS. INTENSITY
PREDICTION IS LAID ON THE HIGHER END OF THE MULTI-MODEL CONSENSUS,
WITH MEDIUM CONFIDENCE, AS ALL MODELS PREDICT INITIALLY STEADY AND
SLOW WEAKENING OVER THE NEXT 36-48 HOURS, FOLLOWED BY RAPID DECAY
AFTERWARDS.

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