WDPN31 PGTW 151500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (BEBINCA) WARNING NR 023//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.5N 124.6E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 165 NM EAST-SOUTHEAST OF SHANGHAI, CHINA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A COMPACT 
CORE, WITH A MOSTLY CLOUD-FILLED EYE AND SPIRAL BANDING, WHICH SUPPORTS 
THE INITIAL POSITION WITH HIGH CONFIDENCE. A 151056Z TROPICS 91 GHZ 
MICROWAVE IMAGE REVEALS A 25 NM DIAMETER MICROWAVE EYE FEATURE, WITH 
CONVECTIVE BANDING SEPARATED TO THE EAST, EXTENDING SOUTH-
SOUTHWESTWARD. THE SYSTEM HAS MAINTAINED RADIAL OUTFLOW, WHICH HAS 
FUELED THE RECENT PERIOD OF INTENSIFICATION. HOWEVER, DRY AIR 
ENTRAINMENT INTO THE WESTERN SEMICIRCLE OF THE SYSTEM HAS CONTRIBUTED 
TO THE SLIGHT WEAKENING TREND OVER THE PAST FEW HOURS. THE INITIAL 
INTENSITY OF 70 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AGENCY 
DVORAK FINAL-T ESTIMATES RANGING FROM T4.0 TO T4.5 (65 TO 77 KNOTS), 
AND A 151200Z ADT ESTIMATE OF 72 KNOTS. THE CURRENT INTENSITY ESTIMATES 
SHOWN BELOW ARE SLIGHTLY HIGHER, RANGING FROM 77-90 KNOTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE
ENTRENCHED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: 4.5 - 77 KTS
   RJTD: 5.0 - 90 KTS
   RCTP: 4.5 - 77 KTS
   KNES: 4.5 - 77 KTS
   CIMSS ADT: 72 KTS AT 151200Z
   CIMSS AIDT: 65 KTS AT 151200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: DRY AIR ENTRAINMENT

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) 14W WILL TRACK WEST-NORTHWESTWARD
UNDER THE STEERING INLUENCE OF THE DEEP-LAYERED SUBTROPICAL RIDGE
(STR) POSITIONED TO THE NORTH THROUGH THE FORECAST PERIOD. TY 14W
SHOULD MAKE LANDFALL NEAR TAU 12, VERY CLOSE TO SHANGHAI AT TYPHOON
STRENGTH. AFTER TAU 12, THE SYSTEM WILL TRACK INLAND WHILE RAPIDLY
DISSIPATING. 

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN TIGHT AGREEMENT, 
WITH A 15 NM CROSS-TRACK SPREAD AT TAU 12, DIVERGING TO ABOUT 50 NM AT 
TAU 36. THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. 
RELIABLE INTENSITY GUIDANCE IS ALSO IN VERY GOOD AGREEMENT, SUPPORTING 
THE RAPID WEAKENING PHASE AFTER TAU 12. 

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