WDPN32 PGTW 261500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (SAOLA) WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.5N 123.1E
   INITIAL INTENSITY: 110 KTS
   GEOGRAPHIC REFERENCE: 212 NM NORTHEAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 50 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A
MEDIUM-SIZED, HIGHLY-SYMMETRICAL SYSTEM THAT HAS DEEPENED OVER THE
LAST SIX HOURS WITH CLOUD TOP TEMPERATURES AROUND THE EYEWALL AS
COLD AS -77 CELSIUS AS IT MAINTAINED A 10-NM, SHARPLY OUTLINED EYE
THAT WAS CONCENTRIC WITH A DEFINED CIRCULATION ON A COMPOSITE RADAR
LOOP. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
THE EYE. THE INITIAL INTENSITY OF 110KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON A 261003Z DIRECT SAR PASS AND SUPPORTED BY THE
HIGH AVERAGE OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE 
SLIGHT 6-HR IMPROVEMENT. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT 
WITH VERY WARM SST IN THE PHILIPPINE SEA, LOW VWS, AND MODERATE RADIAL 
OUTFLOW ALOFT.

INITIAL WIND RADII BASIS: SAR DATA.

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE WEST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   RJTD: T6.0 - 115 KTS
   RCTP: T6.0 - 115 KTS
   KNES: T5.5 - 102 KTS
   CIMSS ADT: 107 KTS AT 261130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TY SAOLA WILL CONTINUE ON ITS CURRENT TRACK
UNDER THE STR TO THE WEST. AFTER TAU 12, A NEAR EQUATORIAL RIDGE TO
THE SOUTH WILL ASSUME STEERING AND DRIVE THE CYCLONE EASTWARD.
AROUND TAU 36, A NORTH-SOUTH EXTENSION OF A SECONDARY DEEP-LAYER
STR TO THE NORTHEAST WILL ASSUME STEERING AND DRIVE THE SYSTEM
NORTHWARD, THEN AROUND TAU 48, THIS SAME STR WILL BUILD AND
ACCELERATE THE SYSTEM NORTHWESTWARD TOWARD TAIWAN VIA THE LUZON
STRAIT. THE FAVORABLE ENVIRONMENT, TEMPERED BY LOCALIZED OCEAN
UPWELLING AND SOME DRY AIR INTRUSION WILL SUSTAIN THE CURRENT 
INTENSITY UP TO TAU 36; AFTERWARD, AS THE CYCLONE SPEEDS UP, A SLIGHT 
INTENSIFICATION TO A PEAK OF 115KTS AT TAUS 36-48 IS EXPECTED. 
AFTERWARD, INCREASING VWS AND LAND INTERACTION WILL GRADUALLY WEAKEN 
THE SYSTEM DOWN TO 90KTS BY TAU 120 AFTER IT REACHES THE TAIWAN 
STRAIT. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT
WITH THIS LOOPING TRACK FORECAST WITH A GRADUAL SPREAD TO JUST 99NM
AT TAU 72 THEN TO 341NM AT TAU 120. JGSM IS ON THE RIGHT MARGIN OF
THE MODEL ENVELOPE AND UEMN IS ON THE LEFT MARGIN. THERE IS OVERALL
MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST.  


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