WDPN32 PGTW 310300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 09W (SAOLA)         
WARNING NR 030//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.0N 118.1E
   INITIAL INTENSITY: 135 KTS
   GEOGRAPHIC REFERENCE: 231 NM EAST-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 46 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
SUPER TYPHOON (STY) 09W IS UNDERGOING AN EYEWALL REPLACEMENT CYCLE
(ERC) AS DEPICTED IN A 302141Z SSMIS 91 GHZ MICROWAVE IMAGE WITH AN
ERODING, SMALL INNER EYEWALL SURROUNDED BY AN INTENSE OUTER
EYEWALL. HOWEVER, THE SYSTEM HAS MAINTAINED STY STRENGTH WITH A 14
NM ROUND EYE, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY OF 135 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE PGTW, KNES AND RCTP DVORAK DATA-T
ESTIMATES OF T7.0 (140 KNOTS) AS WELL AS A CIMSS ADT ESTIMATE OF
134 KNOTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP LAYER SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   RJTD: T7.0 - 140 KTS 
   RCTP: T7.0 - 140 KTS 
   KNES: T7.0 - 140 KTS 
   CIMSS ADT: 134 KTS AT 302330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 KTS
   SST: 30-31 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: STY 09W IS FORECAST TO TRACK WEST-NORTHWESTWARD 
TO WESTWARD THROUGH TAU 48 UNDER THE STEERING INFLUENCE OF A WEAK STR 
TO THE NORTH. STY 09W WILL WEAKEN DUE TO THE ONGOING ERC AND DUE TO 
INTERACTION WITH LAND AS IT APPROACHES SOUTHEAST CHINA. MORE RAPID 
WEAKENING IS ANTICIPATED AS THE SYSTEM TRACKS ALONG THE COAST OF 
CHINA THROUGH TAU 48. AFTER TAU 48, STY 09W WILL GRADUALLY TURN 
SOUTHWARD AS IT ENCOUNTERS A NORTH-SOUTH ORIENTED STR TO THE WEST 
THEN WILL TURN SHARPLY EASTWARD AS THE STEERING INFLUENCE TRANSITIONS 
TO A LOW-LEVEL NEAR-EQUATORIAL RIDGE TO THE SOUTH AND ASSOCIATED 
VIGOROUS SOUTHWESTERLIES.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT
THROUGH TAU 36 WITH A 35 NM CROSS-TRACK SPREAD IN SOLUTIONS AT TAU
36. AFTER TAU 36, GUIDANCE DIVERGES WITH SIGNIFICANT DIFFERENCES IN
THE DEGREE AND TIMING OF THE EASTWARD TURN. DUE TO THE LARGE DEGREE
OF UNCERTAINTY, THERE IS LOW OVERALL CONFIDENCE IN THE JTWC TRACK
FORECAST THROUGH TAU 120. RELIABLE INTENSITY GUIDANCE IS IN FAIR
AGREEMENT THROUGH TAU 120 LENDING MEDIUM CONFIDENCE TO THE JTWC
INTENSITY FORECAST.

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