WDPN31 PGTW 091500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 03W (GUCHOL) WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.3N 130.0E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 507 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A RAGGED,
CLOUD-FILLED EYE WITH INTENSE CONVECTIVE BANDING OVER THE EASTERN
SEMICIRCLE AND WEAKER BANDING OVER THE WESTERN SEMICIRCLE. A
091246Z GMI 89GHZ MICROWAVE IMAGE REFLECTS A GENERAL WEAKENING
TREND WITH AN ERODING EYEWALL OVER THE WESTERN QUADRANT AND THE
BULK OF THE DEEP CONVECTIVE BANDING OVER THE EASTERN AND SOUTHERN
SEMICIRCLES. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE GMI 37GHZ IMAGE SHOWING A WELL-DEFINED MICROWAVE EYE.
UPPER-LEVEL ANALYSIS REVEALS A FAVORABLE ENVIRONMENT WITH RADIAL
OUTFLOW AND A ROBUST EASTWARD OUTFLOW CHANNEL INTO A STRONG UPPER
LOW POSITIONED OVER THE NORTHERN MARIANAS. SST VALUES REMAIN
FAVORABLE AT 28C, HOWEVER, OCEAN HEAT CONTENT VALUES ARE LOW
REFLECTING A SHALLOW WARM LAYER. THE INITIAL INTENSITY OF 80 KTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE DVORAK CURRENT
INTENSITY ESTIMATES AS WELL AS AN AIDT ESTIMATE OF 82 KNOTS. RECENT 
DMINT AND DPRINT OBJECTIVE INTENSITY ESTIMATES HAVE FLUCTUATED BETWEEN 
80 TO 90 KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.5 - 77 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   CIMSS ADT: 92 KTS AT 091130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 20-25 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG EASTWARD

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: TY 03W IS FORECAST TO RECURVE POLEWARD AROUND
THE WESTERN PERIPHERY OF THE STR OVER THE NEXT 12 TO 24 HOURS WITH
GRADUAL WEAKENING EXPECTED AFTER TAU 12. AFTER TAU 36, THE SYSTEM
WILL ACCELERATE ALONG THE NORTHWEST PERIPHERY OF THE STR WITHIN THE
SUBTROPICAL WESTERLIES, WHICH WILL EVENTUALLY LEAD TO SUBTROPICAL
TRANSITION (STT) BY TAU 72. THE FRONTAL ZONE IS EXPECTED TO REMAIN
WELL TO THE NORTH, THEREFORE, EXTRA-TROPICAL TRANSITION IS UNLIKELY
SOUTH OF HONSHU. AFTER TAU 72, ENVIRONMENTAL CONDITIONS WILL
DEGRADE FURTHER WITH INCREASING VERTICAL WIND SHEAR (20-50 KNOTS)
AND COOLING, MARGINAL SST VALUES (25 TO 20C). AS TY 03W TRACKS MORE
POLEWARD, IT WILL INTERACT WITH THE SUBTROPICAL JET AND COMPLETE
STT BY TAU 96.

MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC GUIDANCE REMAINS
IN GOOD AGREEMENT THROUGH TAU 72 WITH A 95NM 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. 


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