WDPN31 PGTW 081500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 03W (GUCHOL) WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.4N 130.8E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 629 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS INDICATED IN ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY,
TYPHOON (TY) 03W HAS CONSOLIDATED OVER THE PAST SIX HOURS AND
FORMED AN OBLONG RAGGED EYE. A 080922Z SSMIS 91GHZ MICROWAVE IMAGE
DEPICTS A COMPLETE EYEWALL SURROUNDING A WELL-DEFINED BUT OBLONG
MICROWAVE EYE FEATURE. THERE IS HIGH CONFIDENCE IN THE INITIAL 
POSITION BASED ON THE EIR IMAGERY AND THE SSMIS IMAGE. ENVIRONMENTAL 
CONDITIONS REMAIN FAVORABLE WITH RADIAL OUTFLOW AND LOW VERTICAL WIND 
SHEAR. SEA SURFACE TEMPERATURES REMAIN CONDUCIVE AT 28 TO 29C. THE 
INITIAL INTENSITY OF 80 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON 
THE PGTW AND RJTD DVORAK ESTIMATES AND AN AIDT ESTIMATE OF 79 KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) POSITIONED TO
THE EAST (WEAK) AND NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.5 - 77 KTS
   KNES: T5.5 - 102 KTS
   CIMSS ADT: 74 KTS AT 081130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 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: TY 03W IS FORECAST TO RECURVE POLEWARD AROUND
THE WESTERN PERIPHERY OF THE STR OVER THE NEXT 48 HOURS WITH A PEAK
INTENSITY OF 100 KNOTS AT TAU 24. AFTER TAU 48, THE SYSTEM WILL
TRACK ALONG THE NORTHWEST PERIPHERY OF THE STR WITHIN THE
SUBTROPICAL WESTERLIES, WHICH WILL EVENTUALLY LEAD TO SUBTROPICAL
TRANSITION (STT) BY TAU 96. THE FRONTAL ZONE IS EXPECTED TO REMAIN
WELL TO THE NORTH, THEREFORE, EXTRA-TROPICAL TRANSITION IS UNLIKELY
SOUTH OF HONSHU. AS TY 03W TRACKS MORE POLEWARD, IT WILL INTERACT
WITH THE SUBTROPICAL JET AND COMPLETE STT BY TAU 120.

MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC GUIDANCE REMAINS
IN GOOD AGREEMENT THROUGH TAU 72 WITH A 90NM CROSS-TRACK SPREAD IN
SOLUTIONS AT TAU 72 LENDING HIGH CONFIDENCE TO THE JTWC FORECAST
TRACK. AFTER TAU 72, DETERMINISTIC GUIDANCE DIVERGES WITH
INCREASING CROSS-TRACK AND ALONG-TRACK SPREAD PROVIDING MEDIUM
CONFIDENCE. THE SYSTEM IS NOT EXPECTED TO IMPACT HONSHU DUE TO THE
PRESENCE OF A STRONG JET OVER AND TO THE SOUTH OF HONSHU. GRADUAL
WEAKENING IS EXPECTED AFTER TAU 36 DUE TO THE STEADILY DEGRADING
ENVIRONMENT ASSOCIATED WITH THE SUBTROPICAL WESTERLIES. AFTER TAU
72, ENVIRONMENTAL CONDITIONS WILL DEGRADE FURTHER WITH INCREASING
VERTICAL WIND SHEAR (20-25 KNOTS) AND COOLING, MARGINAL SST VALUES
(25 TO 21C).

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: HIGH
   INTENSITY 72-120 HR: MEDIUM//
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