WDPN31 PGTW 152100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (BEBINCA) WARNING NR 024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.5N 123.3E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 102 NM EAST-SOUTHEAST OF SHANGHAI, CHINA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 34 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A COMPACT
AND SYMMETRICAL SYSTEM IN THE EAST CHINA SEA WITH MOSTLY DETACHED
SHORT FEEDER BANDS WHOSE CENTRAL DENSE OVERCAST HAS MAINTAINED ITS
OVERALL CONVECTIVE DEPTH AS IT APPROACHED SHANGHAI. THE EIR LOOP
ALSO INDICATES A CONFINED RADIAL OUTFLOW AND COOL DRY AIR INTRUDING
FROM THE SOUTHWESTERN PERIPHERIES. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON A WELL-DEFINED LOW LEVEL CIRCULATION
FEATURE IN A COMPOSITE RADAR LOOP. THE INITIAL INTENSITY IS
ASSESSED BASED ON ASSESSMENT OF WEAKENING DVORAK TRENDS FROM ALL
FOUR REPORTING AGENCIES AND REFLECTS THE SUSTAINED 6-HR CONVECTIVE
SIGNATURE. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH
LOW-MODERATE VWS AND THE DRY AIR INTRUSION OFFSET BY MODERATE
OUTFLOW AND VERY WARM ALONG-TRACK SSTS.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE NORTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   CIMSS ADT: 77 KTS AT 151730Z
   CIMSS AIDT: 73 KTS AT 151730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-20 KTS
   SST: 29-30 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 BEBINCA WILL TRACK WEST-NORTHWESTWARD
UNDER THE STEERING STR, MAKING LANDFALL OVER THE CHINESE EASTERN
SEABOARD JUST SOUTH OF SHANGHAI AROUND TAU 06, THEN DEEPER INTO
RUGGED TERRAIN. INCREASING VWS, DRY AIR INTRUSION, AND LAND
INTERACTION WILL ERODE THE SYSTEM GRADUALLY THEN RAPIDLY TO
DISSIPATION BY TAU 36. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH
AN EVEN AND GRADUAL SPREAD TO A MERE 56NM BY TAU 36, LENDING HIGH
CONFIDENCE TO THE JTWC TRACK FORECAST. GIVEN THE VARIABILITY OF A
LAND TRACK, THERE IS ONLY MEDIUM CONFIDENCE IN THE INTENSITY
FORECAST. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM//
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