WDPN31 PGTW 150900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (BEBINCA) WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.3N 126.0E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 238 NM EAST-SOUTHEAST OF SHANGHAI, CHINA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
EXHIBITING IMPROVED RADIAL OUTFLOW, ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY (MSI) DEPICTS TY 14W DEVELOPED A RAGGED EYE FEATURE AT 
APPROXIMATELY 150200Z. THE SYSTEM TOOK OWNERSHIP OF ITS EXHAUST 
MECHANISM AND IS VENTING CIRRUS FILAMENTS POLEWARD WITHOUT MUCH DIRECT 
SUPPORT FROM THE SURROUNDING ENVIRONMENT. DEEP CONVECTION IS FLARING 
WITHIN THE NORTHERN SEMI-CIRCLE, WHEREAS THE SOUTHEASTERN QUADRANT 
APPEARS TO BE GRAPPLING WITH SOME DRY AIR ENTRAINMENT. THE EYE PROVED 
USEFUL IN LOCATING THE POSITION AND ALSO IN DEMONSTRATING TROCHOIDAL 
MOTION AS THE SYSTEM FLEXED ABOVE FORECASTED INTENSITIES. OBJECTIVE 
INTENSITY AIDS UNDERSHOT THE ASSESSED INTENSITY, WHICH WAS DETERMINED 
USING AGENCY SUBJECTIVE DVORAK ESTIMATES THAT MORE CLOSELY ALIGNED THE 
STRUCTURE OF THE SYSTEM, GIVEN THE EYE. THUS, THE INITIAL INTENSITY OF 
75 KTS IS ASSESSED WITH MEDIUM CONFIDENCE, AND THE INITIAL POSITION IS 
PLACED WITH HIGH CONFIDENCE DUE TO THE EYE.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP SUBTROPICAL RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.5 - 77 KTS
   CIMSS ADT: 59 KTS AT 0630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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: GENEROUS OCEAN HEAT CONTENT VALUES AND WARM SEA 
SURFACE TEMPERATURES WILL CONTINUE TO FUEL A TEMPORARY BOOST IN THE 
STRENGTH OF TY 14W. VERTICAL WIND SHEAR HAS BACKED OFF AND BECOME MORE 
FAVORABLE (10-15 KTS). BASED ON THE DEVELOPMENT OF AN EYE FEATURE AND 
IMPROVED RADIAL OUTFLOW, MILD INTENSIFICATION IS FORECAST TO OCCUR NOW 
THROUGH TAU 12. AS THE SYSTEM CONTINUES WEST-NORTHWESTWARD AT A STEADY 
PACE, ALBEIT WITH SOME ERRATIC MOTION DURING THE PERIOD OF 
STRENGTHENING, IT IS EXPECTED TO MAKE LANDFALL NEAR SHANGHAI BETWEEN 
TAU 12 AND TAU 24. THE LAND INTERACTION WILL CAUSE AN ABRUPT WEAKENING 
TREND, LEADING TO DISSIPATION OVER LAND NO LATER THAN TAU 48.

MODEL DISCUSSION: THE GFS ENSEMBLE (GEFS) AND ECMWF ENSEMBLE (ECENS) 
SHARE GOOD AGREEMENT CONCERNING THE STRAIGHT-RUNNING WEST-NORTHWESTWARD 
TRACK, AND THE LEADING TRACK GUIDANCE CONCURS WITH A LANDFALL LOCATION 
UNCERTAINTY NEAR SHANGHAI OF LESS THAN 30 NM. INTENSITY GUIDANCE HAS 
NOT FULLY CAPTURED THE CURRENTLY EXPERIENCED PERIOD OF STRENGTHENING, 
WHICH IS WHY THE JTWC FORECAST IS INITIALLY HEDGED ABOVE MODEL GUIDANCE 
IN FAVOR OF THE ANALYSIS. ULTIMATELY, ALL MODELS COME INTO AGREEMENT 
CONCERNING A SHARP DECLINE OCCURRING IN THE NEAR TERM OR BY TAU 12 AS 
THE SYSTEM APPROACHES LAND.

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