WDPN31 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 03W (GUCHOL) WARNING NR 014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.8N 130.1E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 537 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RAGGED,
CLOUD-FILLED EYE WITH TIGHTLY-CURVED BANDING WRAPPING INTO THE
CENTER. A 090641Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS AN OBLONG
35-45NM MICROWAVE EYE FEATURE WITH A BREAK IN THE EYEWALL OVER THE
NORTHERN QUADRANT. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE SSMIS 37GHZ MICROWAVE IMAGE, WHICH SHOWS A
WELL-DEFINED LOW-LEVEL CIRCULATION CENTER. 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 85 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED 
ON THE 77-102 RANGE OF DVORAK CURRENT INTENSITY ESTIMATES AS WELL AS 
AN AIDT ESTIMATE OF 84 KNOTS. THE 090500Z AND 090600Z DPRINT ESTIMATES 
OF 87 KNOTS ALSO SUPPORT THE INTENSITY ASSESSMENT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

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 SATCON: 98 KTS AT 090442Z
   CIMSS ADT: 94 KTS AT 090530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG EASTWARD

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 24 TO 36 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 (25-30 KNOTS) AND 
COOLING, MARGINAL SST VALUES (25 TO 21C). 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 115NM 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//
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